Coffee Science Alert n° 13
September 2007
AGRONOMY
Susceptibilidade de seis cultivares de cafe arabica as moscas-das-frutas (Diptera: Tephritoidea) em sistema organico com e sem arborizacao em Valenca, RJ. [Susceptibility of six Arabic coffee cultivars to fruit flies (Diptera: Tephritoidea) under shaded and unshaded organic management in Valenca, State of Rio de Janeiro, Brazil]
Aguiar-Menezes, E. L.; Souza, S. A.; Santos, C. M.; Resende, A. L.; Strikis, P. C.; Costa, J. R.; Ricci, M. S.
The infestation indices by fruit flies were determined for six cultivars of Coffea arabica L. in shaded and unshaded systems under organic management. The experiment was set in a completely randomized design with a split-split-plot arrangement and four replicates. A 250g-sample of maturing fruits per plot was harvested in May 2005. The cultivars Icatu Amarelo and Catucai Amarelo were the least susceptible to attack by tephritids in both systems. As for lonchaeids, Oeiras, Catucai Amarelo and Catuai Vermelho were the least susceptible cultivars in the shaded system, and there was no difference among the cultivars in the unshaded system. The following tephritid species were obtained: Ceratitis capitata (Wiedemann), Anastrepha fraterculus (Wiedemann) and A. sororcula Zucchi (Tephritidae). Lonchaeids were represented by Neosilba bifida Strikis & Prado, N. certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. pseudopendula (Korytkowski and Ojeda), Dasiops rugifrons Hennig, Neosilba n.sp.10 and Neosilba n.sp.14.
Source : Neotrop Entomol 2007 vol.36 (2), pp 268 - 273
Insecticidal Activity of Caffeine Aqueous Solutions and Caffeine Oleate Emulsions against Drosophila melanogaster and Hypothenemus hampei
Araque, P.; Casanova, H.; Ortiz, C.; Henao, B.; Pelaez, C.
The bioactivity of caffeine aqueous solutions (0.20-2.00 wt %) and caffeine oleate emulsions (20 vol % oil, 2.00 wt % surfactant, 0.04 wt % caffeine, 0.05 wt % oleic acid) was assessed against two biological models: Drosophila melanogaster and Hypothenemus hampei. The caffeine aqueous solutions showed no insecticidal activity, whereas caffeine oleate emulsions had high bioactivity against both D. melanogaster and H. hampei. By preparing the caffeine oleate emulsions with anionic surfactants (i.e., sodium lauryl sulfate, sodium laureate, and sodium oleate), we obtained a lethal time 50 (LT50) of 23 min. In the case of caffeine oleate emulsions prepared with nonionic surfactants (i.e., Tween 20 and Tween 80), a LT50 of approximately 17 min was observed. The high bioactivity of the caffeine oleate emulsion against H. hampei opens the possibility of using this insecticide formulation as an effective way to control this pest that greatly affects coffee plantations around the world. Keywords: Caffeine oleate; insecticide; O/W emulsion; Drosophila melanogaster; Hypothenemus hampei.
Source : J Agric Food Chem 2007 vol.55 (17), pp 6918 - 6922
Coffee consumption and risk of liver cancer: a meta-analysis
Larsson, S. C.; Wolk, A.
Mounting evidence indicates that coffee drinking may protect against liver injury and lower the risk of liver cancer. We quantitatively assessed the relation between coffee consumption and the risk of liver cancer in a meta-analysis of epidemiologic studies. METHODS: Relevant studies were identified by searching MEDLINE (from 1966 to February 2007) and the reference lists of retrieved articles. We included cohort and case-control studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) of primary liver cancer or hepatocellular carcinoma by quantitative categories of coffee consumption. Study-specific RRs were pooled using a random-effects model. RESULTS: Four cohort and 5 case-control studies, involving 2260 cases and 239,146 noncases, met the inclusion criteria. All studies observed an inverse relation between coffee consumption and risk of liver cancer, and in 6 studies the association was statistically significant. Overall, an increase in consumption of 2 cups of coffee per day was associated with a 43% reduced risk of liver cancer (RR, 0.57; 95% CI, 0.49-0.67). There was no statistically significant heterogeneity among studies (P = .17). In stratified analysis, the summary RRs of liver cancer for an increase in consumption of 2 cups of coffee per day were 0.69 (95% CI, 0.55-0.87) for persons without a history of liver disease and 0.56 (95% CI, 0.35-0.91) for those with a history of liver disease.
CONCLUSIONS: Findings from this meta-analysis suggest that an increased consumption of coffee may reduce the risk of liver cancer.
Source : Gastroenterology 2007 vol.132 (5), pp 1740 - 1745
Agrobacterium-mediated insertional mutagenesis of the ochratoxigenic fungus Aspergillus westerdijkiae
Mata, M. M.; Taniwaki, M. H.; Iamanaka, B. T.; Sartori, D.; Oliveira, A. L.; Furlaneto, M. C.; Fungaro, M. H.
Aspergillus westerdijkiae is a potent ochratoxin A (OTA) producer that has been found in coffee beans. OTA is known to have nephrotoxic effects and carcinogenic potential in animal species. Here we report for the first time the Agrobacterium-mediated transformation for Aspergillus westerdijkiae and the generation of ochratoxin-defective mutants. Conidia were transformed to hygromycin B resistance using strain AGL-1 of Agrobacterium tumefaciens. The obtained transformation frequency was up to 47 transformants per 10(6) target conidia. Among 600 transformants, approximately 5% showed morphological variations. Eight transformants with consistently reduced OTA production were obtained. Two of these transformants did not produce OTA (detection limit: 0.1 microg/kg); the other six mutants produced lower amounts of OTA (1%-32%) compared with the wild-type strain. By using thermal asymmetric interlaced polymerase chain reaction, we successfully identified a putative flavin adenine dinucleotide monooxygenase gene.
Source : Can J Microbiol vol.53 Issue 1 pp 148 - 151
Comportamento de acasalamento do bicho-mineiro-do-cafeeiro, Leucoptera coffeella (Guerin-Meneville) (Lepidoptera: Lyonetiidae). [Mating behavior of the coffee leaf-miner Leucoptera coffeella (Guerin-Meneville) (Lepidoptera: Lyonetiidae).]
Michereff, M. F.; Michereff-Filho, M.; Vilela, E. F.
Despite the importance of Leucoptera coffeella (Guerin-Meneville) in coffee production worldwide, there is a lack of information on its reproductive biology. This knowledge will help in mass rearing, as well as support the development of behavioral control techniques for this insect. The purpose of the study was to determine the periodicity of mating and male capture and describe the mating behavior L. coffeella. In laboratory, we observed the periodicity of mating with virgin couples of different ages, zero to five days after emergence. Male activity was studied in a 0.7 ha coffee plantation, cv. Catuai, where Delta traps were installed at 0.5 m above ground, using either virgin females or rubber septa lured with the synthetic sex pheromone. The sequence of mating behavior was studied by making visual observations and recorded of pairs placed on individual plastic tubes. Mating occurred between 4h and 6h of photophase, when the highest frequencies involved pairs with ages of one and three days after emergence, with peak of mating occurring in 5th hour of photophase. The young or old pairs showed significantly copulation frequency and the peak of matings advance in 1h. The highest male capture occurred at 12p.m. and 13 p.m. by traps with virgin females or traps with synthetic sex pheromone lures, respectively. L. coffeella is one insect with diurnal mating and the mating behavior was not different from what is know for other Lepidoptera species.
Source : Neotrop Entomol 2007 vol.36 (3), pp 376 - 382
Incorporacion de cafeina en el hongo Pleurotus sajor-caju cultivado sobre pulpa de cafe [Incorporation of caffeine into the macromicete fungus Pleurotus sajor-caju growing on coffee pulp]
Nieto-Ramirez, I. J.; Chegwin-Angarita, C.; Osorio-Zuloaga, H. J.
When the chemical composition of secondary metabolites from the Pleurotus sajor-caju growing on coffee pulp were study, it was found that the fungus has the faculty of incorporating caffeine inside its fructiferous body. Component of the substrate (around 1.3% on dry basis) did not show a structural change over the alkaloid; this constitutes an unexpected outcome for a species belonging to realm of the fungi.
Source : Rev Iberoam Micol 2007 vol.24 Issue 1 pp 72 - 74 (not available on line)
Seasonal mortality factors of the coffee leafminer, Leucoptera coffeella
Pereira, E. J.; Picanco, M. C.; Bacci, L.; Crespo, A. L.; Guedes, R. N.
Seasonal population fluctuation of the coffee leafminer, Leucoptera coffeella (Guerin-Meneville & Perrottet) (Lepidoptera: Lyonetiidae), led to an investigation of its natural mortality factors during the rainy season when the population level is low and during the dry season when population peaks occur. Lifetable data were colleted from insecticide-free plots within a 3 ha coffee plantation on the upper, medium and lower canopy. Leafminer mortality was similar among the canopy parts but varied in the two seasons studied. During the rainy season, the generational mortality averaged 94.3%, with 50.2, 33.7 and 10.4% occurring during egg, larval and pupal stages, respectively. During the dry season, total mortality was 89%, with 13.2, 61.0 and 14.8% occurring during egg, larval and pupal stages, respectively. Marginal mortality rates during the rainy season were highest for physiological disturbances, rainfall and egg inviability; but, in the dry season, they were highest for predaceous wasps, physiological disturbances and parasitoids. Egg and larval stages accounted for most of the mortality variation in the rainy season, while the combination of larval and pupal mortality better described the generational mortality in the dry season. Variation in mortality during the rainy season was primarily associated with egg inviability, rainfall and parasitoids. In contrast, predatory wasps and physiological disturbances were the main factors associated with mortality variation during the dry season. These results suggest that weather conditions, natural enemies and plant quality attributes are the main determinants of the population dynamics of L. coffeella.
Source : Bull Entomol Res 2007 vol.97 (4), pp 421 - 432
Field-testing ecological and economic benefits of coffee certification programs
Philpott, S. M.; Bichier, P.; Rice, R.; Greenberg, R.
Coffee agroecosystems are critical to the success of conservation efforts in Latin America because of their ecological and economic importance. Coffee certification programs may offer one way to protect biodiversity and maintain farmer livelihoods. Established coffee certification programs fall into three distinct, but not mutually exclusive categories: organic, fair trade, and shade. The results of previous studies demonstrate that shade certification can benefit biodiversity, but it remains unclear whether a farmer's participation in any certification program can provide both ecological and economic benefits. To assess the value of coffee certification for conservation efforts in the region, we examined economic and ecological aspects of coffee production for eight coffee cooperatives in Chiapas, Mexico, that were certified organic, certified organic and fair trade, or uncertified. We compared vegetation and ant and bird diversity in coffee farms and forests, and interviewed farmers to determine coffee yield, gross revenue from coffee production, and area in coffee production. Although there are no shade-certified farms in the study region, we used vegetation data to determine whether cooperatives would qualify for shade certification. We found no differences in vegetation characteristics, ant or bird species richness, or fraction of forest fauna in farms based on certification. Farmers with organic and organic and fair-trade certification had more land under cultivation and in some cases higher revenue than uncertified farmers. Coffee production area did not vary among farm types. No cooperative passed shade-coffee certification standards because the plantations lacked vertical stratification, yet vegetation variables for shade certification significantly correlated with ant and bird diversity. Although farmers in the Chiapas highlands with organic and/or fair-trade certification may reap some economic benefits from their certification status, their farms may not protect as much biodiversity as shade-certified farms. Working toward triple certification (organic, fair trade, and shade) at the farm level may enhance biodiversity protection, increase benefits to farmers, and lead to more successful conservation strategies in coffee-growing regions.
Source : Conserv Biol 2007 vol.21 (4), pp 975 - 985
Inoculation of coffee plants with the fungal entomopathogen Beauveria bassiana (Ascomycota: Hypocreales)
Posada, F.; Aime, M. C.; Peterson, S. W.; Rehner, S. A.; Vega, F. E.
The entomopathogenic fungus Beauveria bassiana was established in coffee seedlings after fungal spore suspensions were applied as foliar sprays, stem injections, or soil drenches. Direct injection yielded the highest post-inoculation recovery of endophytic B. bassiana. Establishment, based on percent recovery of B. bassiana, decreased as time post-inoculation increased in all treatments. Several other endophytes were isolated from the seedlings and could have negatively influenced establishment of B. bassiana. The recovery of B. bassiana from sites distant from the point of inoculation indicates that the fungus has the potential to move throughout the plant.
Source : Mycol Res 2007 vol.111 (6), pp 748 - 757
Life history of Amblyseius herbicolus (Chant) (Acari: Phytoseiidae) on coffee plants
Reis, P. R.; Teodoro, A. V.; Pedro-Neto, M.; da Silva, E. A.
The predaceous mite Amblyseius herbicolus (Chant) is the second most abundant phytoseiid on coffee plants (Coffea arabica L), after Euseius alatus DeLeon, in Lavras, MG, Brazil, associated to the vector of the coffee ring spot virus, Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae). Its life history was studied taking into account biological aspects, life table, predatory activity and functional and numerical responses in relation to the density of the prey. The adult female has longevity of 38 days when supplied with B. phoenicis. The intrinsic rate of population increase (r m) was 0.150 and the mean generation time (T) 25.3 days. The population doubles every 4.6 days. Thirty mites B. phoenicis /3-cm diameter coffee leaf arenas were separately offered to one specimen of each predator phase. Adult females were more efficient in killing all developmental phases of B. phoenicis, followed by the nymph stages. For the functional and numerical responses studies, from 0.14 to 42.3 immature specimens of the prey /cm(2) of arena were submitted to the predator, the preferred phase for predation. Predation and the oviposition of A. herbicolus increased with increasing prey density, with a positive and highly significant correlation. Regression analysis suggests a functional type II response, with a maximum daily predation near 35 B. phoenicis /cm(2) /one adult female.
Source : Neotrop Entomol 2007 vol.36 (2), pp 282 - 287
Changes in key odorants of raw coffee beans during storage under defined conditions
Scheidig, C.; Czerny, M.; Schieberle, P.
During storage of raw coffee beans (green coffee) atypical odors may develop, which are suggested to influence the aroma of particularly the coffee beverage. To gain insight into the aroma compounds responsible for such odor changes, a comparative aroma extract dilution analysis was applied on unstored, raw Arabica coffee beans from Colombia (water content = 11.75%) and on the same beans with a water content of 13.5%, which were stored for 9 months at 40 degrees C. In combination with the flavour dilution (FD) factors, the results of the identification experiments showed strong increases in (E)-betadamascenone (cooked apple-like), 2-methoxy-4-vinylphenol (clove-like), and methyl 2-methyl- and methyl 3-methylbutanoate (fruity), whereas others, such as the earthy smelling 3-isopropyl-2-methoxypyrazine as well as 2-phenylethanol and 3-methoxyphenol, remained unchanged during storage. In addition, the previously unknown coffee odorant 2-methoxy-5-vinylphenol (intense smoky odor) increased significantly during storage. Quantitative measurements performed on raw coffee samples stored at various temperatures, water contents, and oxygen availabilities indicated that the significant increase of, in particular, the methyl esters of 2- and 3-methylbutanoic acid were responsible for the pronounced and fruity odor quality perceived in the stored green coffee, whereas the higher concentrations of 2-methoxy-4-vinylphenol and 2-methoxy-5-vinylphenol led to the more pronounced smoky, clove-like odor quality. On the basis of the results obtained, in particular the reduction of the water content in combination with lower temperatures can be suggested to avoid aroma changes in raw coffee beans caused by storage. Keywords: Raw coffee beans; off-odor; aroma extract dilution analysis; 2-methoxy-5-vinylphenol; stable isotope dilution analysis.
Source : J Agric Food Chem 2007 vol.55 (14), pp 5768 - 5775
Sterile insect technique and Mediterranean fruit fly (Diptera: Tephritidae): assessing the utility of aromatherapy in a Hawaiian coffee field
Shelly, T. E.; McInnis, D. O.; Rodd, C.; Edu, J.; Pahio, E.
The sterile insect technique (SIT) is widely used in integrated programs against tephritid fruit fly pests, particularly the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Unfortunately, the mass-rearing procedures inherent to the SIT often lead to a reduction in the mating ability of the released males. One potential solution involves the prerelease exposure of males to particular attractants. In particular, exposure of male Mediterranean fruit flies to ginger, Zingiber officinale Roscoe, root oil (GRO) has been shown to increase mating success in laboratory and field cage trials. Here, we describe a field experiment that compares the level of egg sterility observed in two Hawaiian coffee, Coffea arabica L., plots, with GRO-exposed, sterile males released in one (treated) plot and nonexposed, sterile males released in the other (control) plot. Once per week in both plots over a 13-wk period, sterile males were released, trap captures were scored to estimate relative abundance of sterile and wild males, and coffee berries were collected and dissected in the laboratory to estimate the incidence of unhatched (sterile) eggs. Data on wild fly abundance and the natural rate of egg hatch also were collected in a remote area that received no sterile males. Despite that sterile:wild male ratios were significantly lower in the treated plot than in the control plot, the incidence of sterile eggs was significantly higher in the treated plot than in the control plot. Correspondingly, significantly higher values of Fried's competitiveness index (C) were found, on average, for treated than control sterile males. This study is the first to identify an association between the GRO "status" of sterile males and the incidence of egg sterility in the field and suggests that prerelease, GRO exposure may represent a simple and inexpensive means to increase the effectiveness of Mediterranean fruit fly SIT programs.
Source : J Econ Entomol 2007 vol.100 (2), pp 273 - 282
Infectividade natural por Xylella fastidiosa Wells et al. de cicadelineos (Hemiptera: Cicadellidae) de lavouras cafeeiras do Parana [Natural infectivity of Xylella fastidiosa Wells et al. in sharpshooters (Hemiptera: Cicadellidae) from coffee plantations of Parana, Brazil]
Silva, M. R.; Meneguim, A. M.; Paiao, F. G.; Meneguim, L.; Canteri, M. G.; Leite, R.-P. Jr
Xylella fastidiosa Wells et al., a gram-negative and xylem limited bacterium, causes significative economic on several crops, such as the leaf scorch in coffee. It is transmitted by xylem feeding insects and four sharpshooters species have been reported as vectors of X. fastidiosa in coffee. The objective of this study was to determine the natural infectivity of X. fastidiosa in five species of sharpshooters from coffee trees: Acrogonia citrina Marucci & Cavichioli, Bucephalogonia xanthophis (Berg), Dilobopterus costalimai Young, Oncometopia facialis (Signoret) and Sonesimia grossa (Signoret). Samples were collected from coffee plantations in five counties of the North and Northwest regions of the State of Parana, Brazil, from October 1998 through November 2001. A total of 806 samples containing three to five insects were examined for the presence of X. fastidiosa by using PCR and nested PCR tests. X. fastidiosa was present in samples of all five species of sharpshooters collected in the two coffee regions. The average level of natural infectivity potential was 30.4%. However, this natural infectivity ranged from 2.2% for O. facialis to 68.8% for A. citrina. Sharpshooters collected in the spring tended to have lower natural infectivity of X fastidiosa as compared to those collected in other seasons. The results obtained showed the high potential of dissemination of X. fastidiosa by different insect vectors in coffee trees in Parana.
Source : Neotrop Entomol 2007 vol.36 (2), pp 274 - 281
Residuos de tiametoxam, aldicarbe e de seus metabolitos em folhas de cafeeiro e efeito no controle de Leucoptera coffeella (Guerin-Meneville) (Lepidoptera: Lyonetiidae). [Residues of thiamethoxam, aldicarb and its metabolites in coffee leaves and effect on the control of Leucoptera coffeella (Guerin-Meneville) (Lepidoptera: Lyonetiidae)]
Diez-Rodriguez, G. I.; de Baptista, G. C.; Trevizani, L. R.; Haddad, M. L.; Nava, D. E.
The coffee leaf miner Leucoptera coffeella (Guerin-Meneville), one of the major pests of coffee crops in Brazil, is mainly controlled with insecticides. The objective of this study was to evaluate the residues and the translocation of the insecticide thiamethoxam in coffee leaves, as well as to study its effect on the coffee leaf miner control, comparing it with aldicarb, used as standard. One experiment was set up in the county of Garca, SP from December/2001 to August/2002. The treatments used were: aldicarb 150 G at the rates of 2.25 and 4.50 g a.i./pit, thiamethoxam 10 GR, at the rates of 0.15 and 0.30 g a.i./pit and check. Twig samples were collected prior to and 30 , 60, 90, 120, 150, 180, 210 and 240 days after the application, at three coffee plant heights (lower, middle and upper third), and the percentage of mined leaves was evaluated. The determination of aldicarb residues, including their sulphoxide and sulfone metabolites and of thiamethoxam were performed by gas chromatography with a nitrogen-phosphorus and mass spectrometer detectors, respectively. The results indicated a uniform translocation of both insecticides in all three thirds of the coffee plants when applied to the soil. A higher persistence of thiamethoxam was verified with its residues being found for as far long as eight months following the application, while aldicarb residues, including the sulphoxide and sulfone metabolites, were found only until four to six months after the application. Control of the coffee leaf miner was observed with both insecticides.
Source : Neotrop Entomol 2006 vol.35 (2), pp 257 - 263
Catechol-o-methyltransferase gene polymorphism modifies the effect of coffee intake on incidence of acute coronary events
Happonen, P.; Voutilainen, S.; Tuomainen, T. P.; Salonen, J. T.
The role of coffee intake as a risk factor for coronary heart disease (CHD) has been debated for decades. We examined whether the relationship between coffee intake and incidence of CHD events is dependent on the metabolism of circulating catecholamines, as determined by functional polymorphism of the catechol-O-methyltransferase (COMT) gene. METHODOLOGY/PRINCIPAL FINDINGS: In a cohort of 773 men who were 42 to 60 years old and free of symptomatic CHD at baseline in 1984-89, 78 participants experienced an acute coronary event during an average follow-up of 13 years. In logistic regression adjusting for age, smoking, family history of CHD, vitamin C deficiency, blood pressure, plasma cholesterol concentration, and diabetes, the odds ratio (90% confidence interval) comparing heavy coffee drinkers with the low activity COMT genotype with those with the high activity or heterozygotic genotypes was 3.2 (1.2-8.4). Urinary adrenaline excretion increased with increasing coffee intake, being over two-fold in heavy drinkers compared with nondrinkers (p = 0.008 for trend). CONCLUSIONS/SIGNIFICANCE: Heavy coffee consumption increases the incidence of acute coronary events in men with low but not high COMT activity. Further studies are required to determine to which extent circulating catecholamines mediate the relationship between coffee intake and CHD.
Source : PLoS ONE vol.1 pp e117 (2006)
BIOCHEMISTRY / BIOTECHNOLOGY
Molecular characterization of an ethylene receptor gene (CcETR1) in coffee trees, its relationship with
Bustamante-Porras, J.; Campa, C.; Poncet, V.; Noirot, M.; Leroy, T.; Hamon, S.; Kochko, A. de
To understand the importance of ethylene receptor genes in the quality of coffee berries, 3 full-length cDNA corresponding to a putative ethylene receptor gene (ETR1) were isolated from Coffea canephora cDNA libraries. They differed by their 3'UTR and contained a main ORF and a 5'UTR short ORF putatively encoding a small polypeptide. The CcETR1 gene, present as a single copy in the C. canephora genome, contained 5 introns in the coding region and 1 in its 5'UTR. Alternative splicing can occur in C. canephora and C. pseudozanguebariae, leading to a truncated polypeptide. C. pseudozanguebariae ETR1 transcripts showed various forms of splicing alterations. This gene was equally expressed at all stages of fruit development. A segregation study on an inter-specific progeny showed that ETR1 is related to the fructification time, the caffeine content of the green beans, and seed wt. Arabidopsis transformed etiolated seedlings, which over-expressed CcETR1, displayed highly reduced gravitropism, but the triple response was observed in an ethylene enriched environment. These plants behaved like a lowconcentration ethylene-insensitive mutant thus confirming the receptor function of the encoded protein. This gene showed no induction during the climacteric crisis but some linkage with traits related to quality.
Source : Mol Genetics and Genomics 2007 vol.277(6), pp 701 - 712
Degradation Kinetics of Caffeine and Related Methylxanthines by Induced Cells of Pseudomonas sp
Dash, S. S.; Gummadi, S. N.
In this study, the kinetics of degradation of caffeine and related methylxanthines by induced cells of Pseudomonas sp. was performed. The kinetics data showed that degradation of caffeine, theobromine, and 7-methylxanthine followed Michealis-Menten kinetics. The values of K ( m ) are low for caffeine and 7-methylxanthine and high for theobromine. Degradation of caffeine and theobromine was enhanced in the presence of NADH and NADPH, whereas the degradation of 7-methylxanthine was unaffected. Among the various metal ions tested, Fe(2+) was found to enhance the rate of degradation for all three substrates, whereas Zn(2+) and Cu(2+) inhibited the degradation of caffeine and theobromine but not 7-methylxanthine. The differences in kinetic parameters and cofactor requirement suggest the possibility of the involvement of more than one N-demethylases in the caffeine catabolic pathway in Pseudomonas sp. The induced cells can serve as effective biocatalysts for the development of biodecaffeination techniques.
Source : Curr Microbiol 2007 vol.55 (1), pp 56 - 60
Comparison between a coffee single copy chromosomal region and Arabidopsis duplicated counterparts evidenced high level synteny between the coffee genome and the ancestral Arabidopsis genome
Mahe, L.; Combes, M. C.; Lashermes, P.
The Arabidopsis thaliana genome sequence provides a catalogue of reference genes that can be used for comparative analysis of other species thereby facilitating map-based cloning in economically important crops. We made use of a coffee bacterial artificial chromosome (BAC) contig linked to the S(H)3 leaf rust resistance gene to assess microsynteny between coffee (Coffea arabica L.) and Arabidopsis. Microsynteny was revealed and the matching counterparts to C. arabica contigs were seen to be scattered throughout four different syntenic segments of Arabidopsis on chromosomes (Ath) I, III, IV and V. Coffee BAC filter hybridizations were performed using coffee putative conserved orthologous sequences to Arabidopsis predicted genes located on the different Arabidopsis syntenic regions. The coffee BAC contig related to the S(H)3 region was successfully consolidated and later on validated by fingerprinting. Furthermore, the anchoring markers appeared in same order on the coffee BAC contigs and in all Arabidopsis segments with the exception of a single inversion on AtIII and AtIV Arabidopsis segments. However, the S(H)3 coffee region appears to be closer to the ancestral genome segment (before the divergence of Arabidopsis and coffee) than any of the duplicated counterparts in the presentday Arabidopsis genome. The genome duplication events at the origin of its Arabidopsis counterparts occurred most probably after the separation (i.e. 94 million years ago) of Euasterid (Coffee) and Eurosid (Arabidopsis).
Source : Plant Mol Biol 2007 vol.64 (6), pp 699 - 711
Introgressive hybridization between the allotetraploid Coffea arabica and one of its diploid ancestors, Coffea canephora, in an exceptional sympatric zone in New Caledonia
Mahe, L.; Le Pierres, D.; Combes, M. C.; Lashermes, P.
The importance of introgressive hybridization in plant evolution has long been recognized. Nevertheless, information on gene flow between allopolyploids and their diploid relatives is very limited, even though gene flow could play a major role in polyploid establishment and evolution. Here, we investigated the processes governing hybrid formation and introgression between the allotetraploid Coffea arabica and one of its ancestral diploid progenitors, C. canephora, in a sympatric zone of New Caledonia. The occurrence of a large assortment of hybridization events between the 2 coffee species is clearly established. First-generation hybrids (F1) and post-F1 hybrids were characterized. The involvement of unreduced gametes of C. canephora is suggested, because tetraploid F1 hybrid plants were detected. Moreover, although bidirectional mating was observed, only unidirectional gene flow from C. canephora to C. arabica was noted in post-F1 hybrids. Most of the collected post-F1 hybrid plants exhibited a high level of introgression, and the frequency of introgression observed among the different analyzed loci was homogeneous, suggesting no significant counterselection against introgressions from C. canephora. Overall, the New Caledonian central mountains appear to be a highly favourable environment for introgressive hybridization and a genetic diversity center for C. Arabica.
Source : Genome 2007 vol.50 (3), pp 316 - 324
The structure of two N-methyltransferases from the caffeine biosynthetic pathway
McCarthy, A. A.; McCarthy, J. G.
Caffeine (1,3,7-trimethylxanthine) is a secondary metabolite produced by certain plant species and an
important component of coffee and tea. In this study, the structures of 2 S-adenosyl-L-methioninedependent N-methyltransferases that mediate caffeine biosynthesis in robusta coffee, xanthosine (XR) methyltransferase (XMT) and 1,7-dimethylxanthine methyltransferase (DXMT), were investigated. Both were cocrystallized with the demethylated cofactor, S-adenosyl-L-cysteine, and substrate, either xanthosine or theobromine. Several elements that appear critical for substrate selectivity were revealed. Serine-316 in XMT appears central to the recognition of XR. Likewise, it is suggested that a change from glutamine-161 in XMT to histidine-160 in DXMT is likely to have catalytic consequences. A phenylalanine-266 to isoleucine-266 change in DXMT may also be crucial for the discrimination between mono and dimethyl transferases in coffee. It is suggested that these key residues may be functionally important and could guide future studies with implications for the biosynthesis of caffeine and its derivatives in plants.
Source : Plant Physiology 2007 vol.144(2), pp 879 - 889
Degradation kinetics of caffeine and related methylxanthines by induced cells of Pseudomonas sp
Sucharita-Dash, S.; Gummadi, S. N.
Decaffeination is used in coffee processing to reduce the amount of caffeine in the final product. In this study, the kinetics of degradation of caffeine and related methylxanthines by induced cells of Pseudomonas sp. were studied. Kinetic data showed that degradation of caffeine, theobromine and 7-methylxanthine followed Michaelis-Menten kinetics. The values of Km were low for caffeine and 7-methylxanthine and high for theobromine. Degradation of caffeine and theobromine was enhanced in the presence of NADH and NADPH, whereas the degradation of 7-methylxanthine was unaffected. Among the various metal ions tested, Fe2+ was found to enhance the rate of degradation for all 3 substrates, while Zn2+ and Cu2+ inhibited the degradation of caffeine and theobromine but not 7-methylxanthine. Differences in kinetic parameters and cofactor requirements suggest that >1 N-demethylases may be involved in the caffeine catabolic pathway in Pseudomonas sp. It is concluded that induced cells can serve as effective biocatalysts for the development of biodecaffeination techniques.
Source : Current Microbiology.2007 vol.55(1), pp 56 - 60
Functional characterization of two p-coumaroyl ester 3\'-hydroxylase genes from coffee tree: evidence of a candidate for chlorogenic acid biosynthesis
Venkataramaiah, Mahesh; Million-Rousseau, R.; Ullmann, P.; Chabrillange, N.; Bustamante, J.; Mondolot, L.; Morant, M.; Noirot, M.; Hamon, S.; Kochko, A. de; Werck-Reichhart, D.; Campa, C.
Chlorogenic acid (5-CQA) is one of the major soluble phenolic compounds that is accumulated in green coffee beans. With other hydroxycinnamoyl quinic acids (HQA), this compound is accumulated in particular in green beans of the cultivated species Coffea canephora. Recent work has indicated that the biosynthesis of 5-CQA can be catalyzed by a cytochrome P450 enzyme, CYP98A3 from Arabidopsis. In this study, 2 full-length cDNA clones (CYP98A35 and CYP98A36) that encode putative p-coumaroylester 3'-hydroxylases (C3'H) were isolated from C. canephora cDNA libraries. Recombinant protein expression in yeast showed that both metabolized p-coumaroyl shikimate at similar rates, but that only one hydroxylated the chlorogenic acid precursor p-coumaroyl quinate. It is suggested that CYP98A35 may be the 1st C3'H capable of metabolizing p-coumaroyl quinate and p-coumaroyl shikimate with the same efficiency. The expression patterns of both genes were studied on 4-month old C. canephora plants and higher transcript levels were found in young and in highly vascularized organs for both genes. Gene expression and HQA content seemed to be correlated in these organs. Histolocalization and immunolocalization studies revealed similar tissue localization for caffeoyl quinic acids and C3'H. Results indicated that HQA biosynthesis and accumulation occurred mainly in the shoot tip and in the phloem of the vascular bundles. The lack of correlation between gene expression and HQA content observed in some organs is discussed in terms of transport and accumulation mechanisms.
Source : Plant Molecular Biology 2007 vol.64(1-2), pp 145 - 159
A new 10-min ligation method using a modified buffer system with a very low amount of T4 DNA ligase: the \"Coffee Break Ligation\" technique
Yoshino, Y.; Ishida, M.; Horii, A.
The ligation reaction is widely used in molecular biology. There are several kits available that complete the ligation reaction very rapidly but they are rather expensive. In this study, we successfully modified the ligation buffer with much lower cost than existing kits. The ligation reaction can be completed in 10 min using very low activities such as 0.01 U T4 DNA ligase, and costs only $1 for 100 reactions of 20 mul scale. We name this ligation system the "Coffee Break Ligation" system; one can complete ligation reaction while drinking a cup of coffee, and perform 100 reactions by spending money equivalent to a cup of coffee.
Source : Biotechnol Lett 2007 vol.29 (10), pp 1557 - 1560
Soluble sugars mediate sink feedback down-regulation of leaf photosynthesis in field-grown Coffea arabica
Franck, N.; Vaast, P.; Genard, M.; Dauzat, J.
Source-sink relationships of field-grown plants of Coffea arabica L. cultivar 'Caturra' were manipulated to analyze the contribution of soluble sugars to sink feedback down-regulation of maximal leaf net CO2 assimilation rate (Amax). Total soluble sugar concentration (SSCm) and Amax were measured in the morning and afternoon on mature leaves of girdled branches bearing either high or low fruit loads. Leaf Amax was negatively correlated to SSCm, increased with fruit load and decreased during the day, indicating that limiting sink demand for carbohydrates caused SSCm to accumulate in the leaf tissue which results in down-regulation of Amax. To further analyze source-sink feedback on Amax, we compared Amax of mature, non-sink-limited coffee leaves fed with water or sucrose for 5, 10 or 30 min with that of non-fed control leaves. Sucrose-feeding reduced Amax compared with the control and water feeding treatments, indicating that down-regulation of Amax is related to phloem sucrose concentration in coffee source leaves, independent of SSCm concentration in other leaf tissues. Although sucrose appeared to be more closely related to the mechanism underlying sink feedback down-regulation of Amax in coffee leaves than SSCm, Amax was closely related to SSCm by a nonlinear equation that may be useful for integrating sink limitations in coffee leaf photosynthetic models.
Source : Tree Physiol 2006 vol.26 (4), pp 517 - 525
PROCESSING
Development of cookie formulations containing coffee
Abreu-Andrade-Rodrigues, M. de; Silva-Lopes, G.; Silva-Franca, A.; Motta, S. da
The development of cookie formulations containing coffee was studied. 3 formulations were developed, in which coffee was added as espresso beverage, instant coffee or roasted coffee powder. The average proximate composition (dry basis) of the formulations was 7% moisture, 70% carbohydrates, 8% protein, 21% fat and 1% minerals, resulting in an average calorific value of 499 kcal/100 g product. Both the proximate composition and average calorific value were similar to values reported for existing commercial brands of cookies. Results indicated that the way the coffee was added to the formulation affected the sensory properties of the product as evaluated by flavour and texture profile descriptive analysis. The formulation employing the espresso beverage presented lower values for: cracks, crumbling, presence of dark spots, and coffee and burnt flavours. The product manufactured using the instant coffee powder exhibited higher values for brown colour intensity, shine, coffee and burnt flavours, residual brown sugar flavour and crunchiness and lower values for concavity. Samples made with roasted coffee powder displayed higher values for the presence of dark spots. All 3 formulations showed satisfactory acceptance levels when assessed by children.
Source : Ciencia e Tecnologia de Alimentos.2007 vol.27(1), pp 162 - 169
Tea from a tube
Anon.
Microperforated tube-shaped packs for tea, coffee or granules are described. The tubes, which provide an alternative to traditional tea or coffee bags, can be placed in boiling water and stirred until the required beverage colour and strength are reached.
Source : Verpackungs Rundschau 2007 vol. 58 (4), pp 12-13
Biotransformation of caffeine, cotinine, and nicotine in stream sediments: implications for use as wastewater indicators
Bradley, P. M.; Barber, L. B.; Kolpin, D. W.; McMahon, P. B.; Chapelle, F. H.
Microbially catalyzed cleavage of the imadazole ring of caffeine was observed in stream sediments collected upstream and downstream of municipal wastewater treatment plants (WWTP) in three geographically separate stream systems. Microbial demethylation of the N-methyl component of cotinine and its metabolic precursor, nicotine, also was observed in these sediments. These findings indicate that stream sediment microorganisms are able to substantially alter the chemical structure and thus the analytical signatures of these candidate waste indicator compounds. The potential for in situ biotransformation must be considered if these compounds are employed as markers to identify the sources and track the fate of wastewater compounds in surface-water systems.
Source : Environ Toxicol Chem 2007 vol.26 (6), pp 1116 - 1121
Transient Occurrence of Seed Germination Processes during Coffee Post-harvest Treatment
Bytof, G.; Knopp, S. E.; Kramer, D.; Breitenstein, B.; Bergervoet, J. H.; Groot, S. P.; Selmar, D.
The chemical composition of green coffee and thus the final coffee quality are specifically determined by the mode of post-harvest treatment, i.e. the wet and dry processing. Recently, it was shown that metabolic processes, i.e. germination and, a slightly delayed stress-related metabolism are executed during the course of processing. The specific ambient conditions of either post-harvest treatment may influence differentially the extent and time course of these metabolic reactions; therefore, the incidence and intensity of germination processes in coffee seeds were analysed during processing. Methods Expression of the germination-specific isocitrate lyase was monitored using competitive RTPCRs analyses. Resumption of cell cycle activity and cell division were determined by flow cytometry, as well as by the abundance of beta-tubulin quantified by Western blot analyses. Key Results The extent and the time courses of germination processes in coffee seeds differed significantly between wet and dry processed beans. The highest germination activity occurred 2 d after the onset of wet processing, whereas the corresponding maximum in the course of dry processing appeared about 1 week after the start of post harvest treatment.
Conclusions : As recently shown, there are specific differences in the chemical composition of differentially processed coffee beans. It is concluded that these substantial differences are the consequence of the differential expression of germination processes, i.e. they are the result of differences in the corresponding metabolic activities. The coherence of germination-related metabolism and of expression-specific coffee qualities establishes the basis for a novel approach in coffee research.
Source : Ann Bot.(Lond) 2007 vol.100 (1), pp 61 - 66
Mathematical modeling of caffeine kinetic during solid-liquid extraction of coffee beans
Espinoza-Perez, J. D.; Vargas, A.; Robles, Olvera, V; Rodriguez-Jimenes, G. C.; Garcia-Alvarado, M. A.
The decaffeination of coffee beans by solid-liquid extraction is one of the oldest chemical processes used in the food industry, but its mathematical representation is limited. This paper describes the development of two mathematical models for coffee decaffeination: a rigorous one involving a non-steady diffusion equation for the coffee beans coupled with a macroscopic mass transfer equation for the solvent, and a simplified one, which uses macroscopic mass transfer equations for both beans and solvent. Adequate correlation was observed between the simplified model and experimental data for caffeine in both phases.
Source : J Food Eng 2007vol.81 (1), pp 72-78
Application of the SAFES (systematic approach to food engineering systems) methodology to roasted coffee process
Fito, P. J.; Castello, M. L.; Arguelles, A.; Fito, P.
This work is the application of SAFES technique for roasting bean coffee. The roasting operation was divided in to three changing stages, determined with the beginning of the pyrolysis and the cooling bean. All data were based on bibliographical search, where the raw material was bean coffee (Arabian from Brazil), the roasting operation variables were 200°C of temperature and 12min. of roasting time and the rest of the bibliography data were all the necessary tools to develop all tensors (relationship between components, phases and aggregation state). The energy generated in the pyrolysis reaction is included in the enthalpy variation. The transformation tensor was calculated using the weight loss curve and the roasting tensor described all changes, dehydration, glass transition, sugar degradation and chemical and biochemical reactions. The energy balances are described in enthalpy and entropy variations. In short, the SAFES technique works to describe this operation, is useful to determine and predict all changes in the food matter and permits us to determine the behaviors involved in this operation.
Source : J Food Eng 2007 vol.83 (2), pp 186-192
Optimizing the particle size of ground coffee
Kippax, P.
Particle size is an important variable for many of the diverse products manufactured by the food industry. For some foodstuffs it directly influences critical product quality parameters. For example, the dissolution rates of milk powder, sugar and gravy granules are strongly dependent on particle size. With other materials the relationship is more complex; particle size influences product rheology, which in turn has an impact on customer perception and satisfaction. This article from Malvern Instruments Ltd, of Malvern, Worcestershire, UK, examines the impact of particle size on the properties of ground coffee. Particle size influences both ease of brewing and the flavour of the finished beverage.
Source : Innovations in Food Technology 2007 vol.(34), pp 88 - 89 & Malvern
Consumer-driven development: coffee beverage mindsets for three commercial venues
Moskowitz, H.; Katz, R.; Krieger, B.; Cappuccio, R.
The increase in out-of-home, ready-to-drink coffee consumption in the US may be attributable to the increasing choice of coffee-based products available, making the development of new products a major opportunity for commercial venues. This paper presents some of the findings from a large-scale development study on coffee, relating to new concepts designed for three different types of coffee venue: Burger King, Dunkin Donuts and Starbucks. Using rating scales appropriate for the different venues, the researchers were able to identify which characteristics of coffee beverages are suitable for particular venues. In addition to showing small differences between the coffee features that fit each venue, the survey also identified groups of individuals wanting radically different products in all venues.
Source : J Foodservice 2007 vol.18 (1), pp 7-22
The effect of roasting method on headspace composition of robusta coffee bean aroma
Nebesny, E.; Budryn, G.; Kula, J.; Majda, T.
Robusta coffee beans were roasted by 3 methods: convectively at 230°C for 590 s; by microwaves at 700 W for 670 s; and by the coupled convective-microwave method (simultaneous convective heating at 230°C and microwaving at 700 W) for 370 s. The ultimate temp. of conventional, microwave and combined roasted beans was 238, 207 and 228°C, respectively. Volatile compounds were determined in the headspace by GC-SPME, both in samples of roasted coffee and in green beans. 82 and 148 odorants were identified in green and roasted coffee, respectively. The highest contents of the latter were found in coffee roasted by the coupled method because both the relatively short time of roasting and moderately high final temp. of beans enhanced retention of volatile compounds. For the same reasons, contents of aroma compounds were lowest in convectively roasted coffee .
Source : Eur Food Res Technol 2007 vol.225(1), pp 9 - 19
Heavy metals in wet method coffee processing wastewater in soconusco, chiapas, Mexico
Siu, Y.; Mejia, G.; Mejia-Saavedra, J.; Pohlan, J.; Sokolov, M.
One of the driving forces of the economy in southeast Mexico is agriculture. In Soconusco, Chiapas, coffee is one of the main agricultural products and is traded on the international market. Coffee grown in this region is processed using the wet method in order to be commercialized as green coffee. In the beneficio (coffee processing plant) water is an essential resource which is required in great quantities (Matuk et al., 1997; Sokolov, 2002) as it is used to separate good coffee berries from defective ones, as a method of transporting the coffee berries to the processing machinery, in the elimination of the berry husk from the coffee grains (pulping) and finally in the post-fermentation washing process. This process gives rise to one of the smoothest, high-quality coffees available (Zuluaga, 1989; Herrera, 2002). Currently, many producers in Soconusco are opting for ecological coffee production, which has, among its many criteria, human health and environmental protection (Pohlan, 2005). Furthermore, increasing concern during the past few years regarding the production of food that is free from contaminants such as heavy metals, and recent environmental policies in relation to aquatic ecosystem protection, have given rise to questions concerning the quality of water used in coffee processing, as well as pollutants produced by this agroindustry. Water used in the coffee processing plants originates from the main regional rivers whose hydrological basins stretch from the Sierra Madre mountain range down to the coastal plain. As well as providing water, these rivers also receive the wastewater produced during coffee processing (Sokolov, 2002).
Source : Bull Environ Contam Toxicol 2007 vol.78 (5) pp 400 - 404
CHEMISTRY / SENSORICS
Comprehensive analysis of major and minor chlorogenic acids and lactones in economically relevant Brazilian coffee cultivars
D. Perrone, A. Farah, C. M. Donangelo, T. de Paulis, P. R. Martin
Coffee is the most consumed beverage in the world and a significant source of phenolic compounds, particularly chlorogenic acids (CGA). During coffee roasting, some CGA are partially transformed into chlorogenic acid lactones (CGL). Both CGA and CGL are important compounds for flavor and potentially beneficial to human health. In the present study, using LC–MS and synthetic standards, we investigated major and minor CGA and CGL isomers in green and roasted samples of economically relevant Brazilian Coffea arabica and Coffea canephora coffee cultivars. For the first time, in addition to nineteen previously identified CGA and CGL, 1-feruloylquinic acid, 1-feruloylquinic lactone and 3,4-diferuloylquinic acid were quantified in C. arabica and C. canephora, the contents of 3- and 4-pcoumaroylquinic lactones were reported in C. canephora and 3,4-di-p-coumaroylquinic acid was identified in C. arabica. Despite their low concentrations, the implications of these findings for flavor, cup quality and the biological properties of coffee merit further investigation.
Source : Food Chem 2008 vol.106, pp 859-867
Chlorogenic acid and caffeine contents in various commercial brewed coffees
K. Fujioka, T. Shibamoto
Twelve commercial brewed coffees (seven regular and five decaffeinated) were analyzed for chlorogenic acids (CGA) and caffeine by HPLC. Their pH and UV–Vis absorbances were also measured. The CGAs identified were three caffeolylquinic acids (3-CQA, 4-CQA, and 5-CQA), three feruloylquinic acids (3-FQA, 4-FQA, and 5-FQA), and three dicaffeoylquinic acids (3,4-diCQA, 3,5-diCQA, and 4,5-diCQA). The total CGAs ranged from 5.26 mg/g to 17.1 mg/g in regular coffees and from 2.10 mg/g to 16.1 mg/g in decaffeinated coffees. Among CGA, 5-CQA was present at the highest level, ranging from 2.13 mg/g to 7.06 mg/g coffee, and comprising 36–42% and 37–39% of the total CGA in the regular and decaffeinated coffees, respectively. CGA isomer contents were, in decreasing order, 5-CQA > 4-CQA > 3-CQA > 5-FQA > 4-FQA > 3-FQA > 3,4-diCQA > 4,5-diCQA, 3,5-diCQA. The caffeine content in regular and decaffeinated coffees ranged from 10.9 mg/g to 16.5 mg/g and from 0.34 mg/g to 0.47 mg/g, respectively. The pH of regular and decaffeinated coffees ranged from 4.95 to 5.99 and from 5.14 to 5.80, respectively. The relationship between the pH and the UV–Vis absorbance at 325 nm was moderately correlated (R2 = 0.7829, p < 0.001, n = 12).
Source : Food Chemistry 2008 vol. 106, pp 217 - 221
Two for the price of one: antioxidant dietary fibre
Alexander, C.
Fruit by-products are the best source of antioxidant dietary fibre (AODF), as they contain high levels of bioactive compounds in addition to fibre. It is suggested that a good source of AODF should contain at least 50% of dietary fibre on a dry matter basis, and that one gram of AODF should have the same capacity to inhibit lipid oxidation as at least 200 mg vitamin E, and a free-radical-scavenging ability equivalent to that provided by 50 mg vitamin E. The properties of AODF isolated from grapes are described. Research currently ongoing examining the properties of AODF from coffee beans is also discussed.
Source : Food Eng Ingred 2007 vol.32 (1), pp 18-19 (not available on line)
Factors influencing the norharman and harman contents in espresso coffee
Alves, R. C.; Casal, S.; Oliveira, B. P.
Espresso coffee (EC) brews were analyzed for beta-carboline [norharman (NH) and harman (H)] contents, by RP-HPLC with fluorescence detection. The influence of the coffee species (arabica or robusta), the roast degree, and the brew length was studied. The results show that the content of NH and H in EC is dependent primarily on the coffee species, followed by brew length. The roast degree has only a minor influence on the final content of NH and H in EC. When compared with other coffee brews, EC has an amount of these beta-carbolines (in micrograms per liter) similar to that of mocha coffee, both being more concentrated than filter and press-pot coffees. Therefore, the consumer's preferences will determine the amount of NH and H ingested daily. For the caffeinated 30 mL of EC, the arabica coffees contain about 4.08 microg of NH and 1.54 microg of H. Commercial blends (usually with a maximum of 30% robusta) range from the cited arabica values to 10.37 microg of NH and 4.35 microg of H.
Source : J Agric Food Chem 2007 vol.55 (5), pp 1832 - 1838
The caffeine contents of dietary supplements commonly purchased in the US: analysis of 53 products with caffeine-containing ingredients
Andrews, K. W.; Schweitzer, A.; Zhao, C.; Holden, J. M.; Roseland, J. M.; Brandt, M.; Dwyer, J. T.; Picciano, M. F.; Saldanha, L. G.; Fisher, K. D.; Yetley, E.; Betz, J. M.; Douglass, L.
As part of a study initiating the development of an analytically validated Dietary Supplement Ingredient Database (DSID) in the United States (US), a selection of dietary supplement products were analyzed for their caffeine content. Products sold as tablets, caplets, or capsules and listing at least one caffeine containing ingredient (including botanicals such as guarana, yerba mate, kola nut, and green tea extract) on the label were selected for analysis based on market share information. Two or three lots of each product were purchased and analyzed using high-pressure liquid chromatography (HPLC). Each analytical run included one or two National Institute of Standards and Technology (NIST) Standard Reference Materials (SRMs) and two products in duplicate. Caffeine intake per serving and per day was calculated using the maximum recommendations on each product label. Laboratory analysis for 53 products showed product means ranging from 1 to 829 mg caffeine/day. For products with a label amount for comparison (n = 28), 89% (n = 25) of the products had analytically based caffeine levels/day of between -16% and +16% of the claimed levels. Lot-to-lot variability (n = 2 or 3) for caffeine in most products (72%) was less than 10%.
Source : Anal Bioanal Chem 2007 vol.389 (1), pp 231 - 239
Impact of the roasting degree of coffee on the in vitro radical scavenging capacity and content of acrylamide
Summa C.A.; Calle B. de la; Brohee M.; Stadler R.H.; Anklam E.
Due to the recognized toxicity of acrylamide, intensive efforts have been made to reduce the concentration of this undesired Maillard by-product in food. This work reports the results obtained from a series of experiments aimed at determining the concentration of acrylamide and the in vitro radical scavenging capacity in the same roasted and ground coffee samples, as it is well established that a significant part of the antioxidant activity in coffee is linked to the melanoidins, which are also considered as Maillard reaction products (MRPs). The radical scavenging capacity was measured using electroparamagnetic resonance (EPR). Coffee samples from the Robusta and Arabica varieties were roasted at 236 °C over different time periods to obtain very light, light, medium and dark roast. Color analyses were performed on all samples. Increasing the roasting degree led to a decrease in acrylamide concentration as well as radical scavenging capacity. The results of this work indicate that any mitigation efforts must also take into account the potential loss of desired food constituents and consequently changes to the risk/benefit characteristics of foods.
Source : LWT Food Sci technol 2007 vol. 40 (10), pp 1849 - 1854
Determination of acrylamide levels in selected foods in Brazil
Arisseto, A. P.; Toledo, M. C.; Govaert, Y.; Loco, J. V.; Fraselle, S.; Weverbergh, E.; Degroodt, J. M.
Selected carbohydrate-rich foods available on the Brazilian market (111 samples representing 19 product categories) were analysed for acrylamide content using a liquid chromatography-tandem mass spectrometry method. A limit of detection of 10 microg kg(-1), a limit of quantitation of 20 microg kg(-1) and mean recoveries ranging 100 to 115% were obtained during a laboratory validation procedure. The concentration of acrylamide in the samples ranged from <20 to 2528 microg kg(-1), with a considerable variation between individual foodstuffs within the same food product class. The highest levels were found in potato products processed at high temperature and in instant coffee, while the lowest concentrations were detected in cassava- and maize-based products, bread and beer. These results are comparable with those reported in other countries.
Source : Food Addit Contam 2007 vol.24 (3), pp 236 - 241
Melanoidins from coffee infusions. Fractionation, chemical characterization, and effect of the degree of roast
Nunes, F. M.; Coimbra, M. A.
A method involving fractionation in ethanol aqueous solutions, anion exchange chromatography, and immobilized Cu chelating chromatography was developed to obtain high mol. wt. anionic melanoidin populations from coffee infusions. 6 anionic fractions with different physicochemical properties (ethanolsolubility and chelating ability) and chemical composition regarding carbohydrate as well as protein nature and content were isolated. Fractions with similar chemical composition were obtained for light-, medium-, and dark-roasted coffee infusions. These melanoidin fractions accounted for 30-33% of the cold-water soluble high mol. wt. material, independently of the degree of roast in coffee. The nature and abundance of the different polysaccharides in each fraction were dependent on their ethanol solubility. The 50% ethanol insoluble melanoidin populations contained mostly galactomannan-like carbohydrates, and the fractions obtained with 75% ethanol contained mostly arabinogalactan-like carbohydrates. The melanoidin populations with chelating properties presented significantly lower carbohydrate content and, from these, the 75% ethanol soluble fractions were almost devoid of carbohydrate material. The results obtained suggest that the chelating ability of these coffee melanoidins is modulated by their carbohydrates.
Suorce : J Agric Food Chem 2007 vol.55(10), pp 3967 - 3977
Influence of water quench cooling on degassing and aroma stability of roasted coffee
Baggenstoss, J.; Poisson, L.; Luethi, R.; Perren, R.; Escher, F.
Coffee roasting experiments with air cooling versus water quench cooling were carried out on laboratory scale with a fluidized-bed hot air roasting system (200 g batch size) and on production scale with a rotating bowl roaster (320 kg batch size). Two series of coffees with different water contents resulted, which were stored at 25 degrees C under normal atmospheric conditions. Carbon dioxide desorption was followed and stability of selected aroma compounds was tested with headspace solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and stable isotope labelled compounds as internal standards. Degassing is faster in water-quenched coffees with higher moisture content, but pore size distribution in the different coffee samples did not correlate with degassing behavior. Bean firmness, which increases with increasing moisture content, might have an influence on degassing. Air- and water-quenched coffees exhibit similar stability of most aroma compounds despite different degassing behavior. However, evolution of dimethyl trisulfide was different in coffees with increased water content. This suggests higher thiol oxidation rates, a factor that is cited to be related to a faster loss of freshness attributes.
Source : J Agric Food Chem 2007 vol.55 (16), pp 6685 - 6691
Identification of phenolic acids in coffee (coffea arabica L.) dust and its antioxidant activity
Baggio, J.; Lima, A.; Mancini-Filho, J.; Fett, R.
Natural antioxidants present in by-products of the coffee industry have attracted interest because theyare related to the reduction of oxidative stress. Furthermore, the phenolic acids present in coffee beans play an important role as oxidative inhibitors. Dust is generated during the process of peeling the coffee bean. Ether, alcohol and aqueous extracts of coffee dust were obtained by sequential extraction and the effect of these solvents (ether, alcohol and water) on the total phenols contents and total antioxidative activity (TAA) was studied. Concn. of phenolic compounds ranged from 288.64 to 424.48 mg and are expressed as gallic acid equivalents (GAE), according to the Folin-Ciocalteau method. The TAA was investigated by the beta-carotene/linoleic acid system and the ABTS method, which quantifies the quenching of this radical spectroscopically. By using this method, the Trolox Equivalent Antioxidant Capacity (TEAC) values for ether, alcohol and aqueous extracts were 735.27, 235.57 and 121.06, respectively. Levels of free (FPA), esterified (EPA) and insoluble-bound phenolic acids (IPA) were 4620.94, 2013.26 and 2796.56 mg, expressed as gallic acid equivalents, respectively. GC analysis showed that salicylic acid was the main component with a concn. >90% in all phenolic acid fractions of the dust. A high correlation between the content of phenolic compounds and the antioxidant index was found. The order of antioxidant activity (TEAC) in different solvents was etheric > alcoholic > aqueous. Results suggest that coffee residues are an excellent source of natural antioxidants.
Source : Ital J Food Sci 2007 vol.19(2), pp 191 - 201
Determination of ochratoxin A at parts-per-trillion levels in cereal products by immunoaffinity column cleanup and high-performance liquid chromatography/mass spectrometry
Chung, S. W. C.; Kwong, K. P.
Ochratoxin A (OTA) can be found in a variety of food commodities, including cereal products, coffee and wine, through fungal contamination of crops, particularly those not properly dried. This paper describes the development and validation of a method for the determination of OTA in cereal products by reverse-phase liquid chromatography (LC) with mass spectrometric (MS) detection, using ochratoxin B as internal standard. The method, which involves extraction of OTA from cereal products with acetonitrile water and clean-up on an immunoaffinity column before LC/MS analysis, was shown to be highly sensitive, with a decision limit of 0.012 ppb and detection capability of 0.021 ppb. It gave recoveries of 103-106% from rice samples spiked with 0.05-0.15 ppb OTA. The procedure was used to determine OTA contents of rice, wheat, rye and other cereal products commercially available in Hong Kong, and found levels well below the EU limit of 3 ppb.
Source : J AOAC Intern 2007. vol. 90 (3), pp 773-777
A review of the occurrence, formation and analysis of furan in heat-processed foods
Crews, C.; Castle, L.
The occurrence in foods of the potential carcinogen furan is reviewed in sections covering: surveys of the occurrence of furan in foods, particularly those conducted by the US FDA and European Food Safety Authority; furan levels in foods not cooked in closed containers and in coffee; effects of domestic cooking on furan formation; metabolism, toxicity and genotoxicity of furan; methods used for analysis of furan (sample preparation, headspace analysis, GC-MS); reactions leading to formation of furan, including those from carbohydrates, ascorbic acid and fatty acids; estimated dietary exposure to furan; and potential approaches for reducing furan level in foods.
Source : Trends Food Sci Techn 2007 vol.18 (7), pp 365 - 372
Awaken olfactory receptors of humans and experimental animals by coffee odourants to induce appetite
Dorri, Y.; Sabeghi, M.; Kurien, B. T.
Smell and its mechanism has been of interest to scientists for many years. Smell, not only provides a sensual pleasure of food and perfumes for humans but also reminds us of past memories, thoughts, locations and finally warns of dangers such as fire. One of the uses of coffee beans is on perfume counters, enabling people to distinguish between perfume fragrances. We hypothesize that coffee can be also used to refresh olfactory receptors after cooking, since people usually experience loss of appetite after cooking. We have experienced an increase in appetite, after cooking, by smelling coffee beans. This is probably due to the detachment of food odourants from olfactory receptors by the coffee odourant molecules. We also think that coffee smell could be used in animal research studies, to keep animals healthy by stimulating their appetite. In a recent study, 28 different odourants have been identified from coffee. One or more of these odourants may have strong binding affinity to olfactory receptors which results in detachment of other odourants from the receptors. The high vibration intensity from coffee odourant molecules may cause the detachment of food odourant from olfactory receptors. Another hypothesis might be the unique structure of these coffee odourants. Studies need to be done to investigate the effect of coffee smell on salivary flow and appetite in animals and humans.
Source : Med Hypotheses 2007 vol.69 (3), pp 508 - 509
Interfacial properties of coffee-based beverages
Ferrari, M.; Navarini, L.; Liggieri, L.; Ravera, F.; Suggi-Liverani, F.
The coffee brewing technique enhances several surface phenomena such as foam and emulsion formation and stabilisation. Recently the authors have investigated the different contribution of the components of commercially available coffees, namely, arabica and robusta coffees. In the present work, dynamic experimental techniques such as maximum bubble pressure and contact angle were used to characterise the air-coffee beverage interface at two different temperatures (20 and 37°C). Different coffee-based beverages were investigated ranging from espresso to soluble coffee. Beverage samples were prepared, using different brewing times and methods, following standard procedures and using commercially relevant varieties and products. The role of the chemical components on tensiometric behaviour of the beverage is discussed. This behaviour is definitely related to the good wetting properties of the beverage on oral mucosa.
Source : Food Hydrocolloids 2007 vol.21(8), pp 1374 - 1378
Olfaction, where nutrition, memory and immunity intersect
German, I. B.; Yeritzian, C.; Tolstoguzov, V. B.
This chapter looks at olfaction, and presents information and discussion under the following headings: introduction; memory consolidation - short-term, long-term and permanent memories; multidimensional biomemory; flavour sensation as a part of personal dietary choices; measuring flavour perception is influenced by several factors; the 'melody' of coffee; metabolomics and the metabolic response to foods; profiling of postprandial plasma lipid composition; profiling signalling lipids; and conclusion. Considerable schematic and tabulated data are included in this chapter.
Conclusions : The development of mechanisms that simultaneously protect and nourish an organism within a particular environment is key to survival, and these mechanisms represent an important Darwinian selective pressure. The ability of organisms to learn from their surroundings and to improve their biochemical responses to that environment is becoming increasingly well established as forms of imprinting and metabolic memory. Within this context, the development of olfactory preferences is a vivid example of acquired memories. Food is not only a source of nutrients, but also the chemicals that elicit characteristic volatile aromas and lead to preferences for particular food choices. Ideally, the memories formed in response to exposures to diets enhance an individual’s ability to succeed in a particular environment, including the available foods. However, the failure of modern diets to deliver increasing health to the entire population is testament to the inability of all humans to match food choices to optimal nutritional requirements in all environments and lifestyles. The ability to reformulate food commodities and foods with widely varying nutritional and flavour properties has the potential to both confound and enhance the processes of flavour preference and food choice. Enhancing food choices based on flavour preferences will require an understanding of precisely how flavour preferences are developed. The tools to simultaneously measure aroma exposure, aroma perception and metabolic responses to foods are at hand. Bringing these tools to practice and joining the fields of flavour science, nutrition and metabolic assessment into a new era of personalised diet and health is an attractive possibility.
In vitro antioxidant activity of coffee compounds and their metabolites
Gomez-Ruiz, J. A.; Leake, D. S.; Ames, J. M.
In this paper we report the antioxidant activity of different compounds which are present in coffee or are produced as a result of the metabolism of this beverage. In vitro methods such as the ABTS*+ [ABTS = 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] decolorization assay and the oxygen radical absorbance capacity assay (ORAC) were used to assess the capacity of coffee compounds to scavenge free radicals. The importance of caffeine metabolites and colonic metabolites in the overall antioxidant activity associated with coffee consumption is shown. Colonic metabolites such as m-coumaric acid and dihydroferulic acid showed high antioxidant activity. The ability of these compounds to protect human lowdensity lipoprotein (LDL) oxidation by copper and 2,2'-azobis(2-amidinopropane) dihydrochloride was also explored. 1-Methyluric acid was particularly effective at inhibiting LDL oxidative modification. Different experiments showed that this caffeine metabolite is not incorporated into LDL particles. However, at physiologically relevant concentrations, it was able to delay for more than 13 h LDL oxidation by copper. Keywords: Coffee; antioxidant activity; LDL; ORAC; ABTS; coffee metabolites.
Source : J Agric Food Chem 2007 vol.55 (17), pp 6962 - 6969
Occurrence of ochratoxin-A (OT-A) in green and commercial coffee samples
Gopinandhan, T. N.; Velmourougane, K.; Panneerselvam, P.; Keshamma, E.; Raghuramulu, Y.
A total of 148 coffee samples were tested for ochratoxin A (OTA). The samples were collected in India and included green coffees (Parchment and Cherry, var. Arabica and Robusta), monsooned and organic coffees, as well as commercial roasted, ground and soluble coffees. Of the samples tested, 68 and 13% were contaminated with 0.1-1.0 and 1.1-5.0 ppb OTA, respectively. 3 samples contained >5 ppb OTA. The highest level of contamination (11.7 ppb) was found in a Robusta Cherry sample. In conclusion, the majority of the Indian coffee samples analysed contained insignificant levels of OTA.
Source : J Food Sci Technol 2007 vol.44(3), pp 247 - 249 (not yet available on line)
Differentiation of market coffee and its infusions in view of their mineral composition
Grembecka, M.; Malinowska, E.; Szefer, P.
The concentrations of 14 elements (Ca, Mg, K, Na, P, Co, Mn, Fe, Cr, Ni, Zn, Cu, Cd, Pb) were determined in market coffee samples after dry mineralisation of both dry samples and infusions evaporated to dryness. The total metal contents were analysed by flame atomic absorption spectrometry (F-AAS) using deuterium-background correction. Phosphorus was determined in the form of phosphomolybdate by spectrophotometric method. Reliability of the procedure was checked by the analysis of the certified reference materials Tea (NCS DC 73351), Cabbage (IAEA-359) and Spinach leaves (NIST-1570). It was concluded, based on RDA calculated for essential metals, that coffee infusions are not an important source of bioelements in human diet. In the case of toxic elements Provisional Tolerable Weekly Intake (PTWI) was estimated and there is no health hazard associated with exposure to Cd and Pb via coffee consumption. Significant correlation coefficients (p<0.001, p<0.01 and p<0.05) were found between concentrations of some metals in coffee. Factor analysis and canonical analysis were applied to the data processing in order to characterise the market coffee samples. The 12 metals determined were considered as chemical descriptors of each sample. Based on the mineral composition, it was possible to differentiate chemometrically particular types of coffee distinguishing arabica from robusta, ground from instant coffee, and their infusions.
Source : Sci Total Environ vol.383 (1-3), pp 59 - 69
Survey of Vietnamese coffee beans for the presence of ochratoxigenic Aspergilli
Ilic, Z.; Bui, T.; Tran-Dinh, N.; Dang, M.-H. V.; Kennedy, I.; Carter, D.
Vietnamese coffee beans were investigated for the presence of ochratoxigenic Aspergillius spp. Results showed that 93% of coffee samples were positive for Aspergillus niger, which was the only ochratoxigenic species present. HPLC analysis determined that 8.7% of A. niger strains produced ochratoxin A (OA). There was no significant difference in the level of contamination or incidence of toxigenic strains in samples that had been rejected by manual sorting and those that were destined for human consumption. No OA-producing fungi were found in a freshly-harvested coffee bean sample, suggesting that OA contamination occurs post-harvest.
Source : Mycopathologia 2007 vol.163(3), pp 177 - 182
gamma-Tocopherol as a marker of Brazilian coffee (Coffea arabica L.) adulteration by corn
Jham, G. N.; Winkler, J. K.; Berhow, M. A.; Vaughn, S. F.
The adulteration of coffee with cereals, coffee twigs, etc. is apparently widespread in Brazil with corn being considered the most widely used. No adequate methods are available to detect such contamination in commercial coffee. A new method, based on high-performance liquid chromatography (HPLC) tocopherol determination was developed to detect coffee adulteration by corn. Percentages of alpha-, beta-, gamma-, and delta-tocopherol determined by HPLC in six coffee varieties were 29.0, 61.7, 3.3, and 6.0, respectively. Similar values were obtained in six popular coffee brands. The percentages of alpha-, gamma-, and delta-tocopherol in six corn samples were 3.6, 91.3, and 5.1, respectively. These differences could be applied to detect corn in a pure coffee sample intentionally contaminated with corn with the best result obtained with gamma-tocopherol. With this methodology, one coffee brand was apparently adulterated (8.9%), most likely with corn. Tocopherol fingerprinting offers the potential to detect adulteration. Keywords: Coffee; adulteration; corn; tocopherols.
Source : J Agric Food Chem 2007 vol.55 (15), pp 5995 - 5999
Caffeine as a flavor additive in soft-drinks
Keast, R. S.; Riddell, L. J.
Over 60% of soft-drinks sold in the United States contain caffeine, a mildly addictive psycho-active chemical, as a flavor additive. Using sweeteners as controls, we assessed whether caffeine has flavour activity in a cola soft-drink. A forced-choice triangle discrimination methodology was used to determine detection thresholds of caffeine in sweeteners and a cola beverage. The subjects (n=30, 28 female, 23+/- 4 years old) were trained tasters and completed over 1600 discrimination tests during the study. The mean detection thresholds for caffeine in the sweet solutions were: 0.333+/-0.1mM sucrose; 0.467+/-0.29 mM aspartame; 0.462+/-0.3mM sucralose, well below the concentration in common cola beverages (0.55-0.67 mM). A fixed concentration of caffeine, corresponding to the concentration of caffeine in a common cola beverage (0.67 mM) was added to the sweeteners and a non-caffeinated cola beverage. Subjects could distinguish between caffeinated and non-caffeinated sweeteners (p<0.001), but all subjects failed to distinguish between caffeinated and non-caffeinated cola beverage (p=1.0). Caffeine has no flavor activity in soft-drinks yet will induce a physiologic and psychologic desire to consume the drink.
Source : Appetite 2007 vol.49 (1), pp 255 - 259
Profile and levels of bioactive amines in instant coffee
Leite-da-Silveira, T. M.; Tavares, E.; Abreu-Gloria, M. B.
The levels of ten free bioactive amines, as well as pH and color characteristics, were determined in different types and brands of instant coffee. The amines were extracted with trichloroacetic acid and quantified by ion-pair HPLC, post-column derivatization with o-phthalaldehyde and fluorimetric detection. Overall, nine amines were detected: serotonin, cadaverine, tyramine, spermidine, putrescine, histamine, agmatine, phenyletylamine and spermine. Tryptamine was not detected in any sample. Tyramine was present in every sample, followed by cadaverine and serotonin. Total amine levels in the dry instant coffee aried from 0.28 to 2.76mg/100g. Overall, serotonin was present at higher levels followed by cadaverine, tyramine and spermidine. Significantly higher tyramine levels were found in decaffeinated coffee and higher cadaverine levels were detected in decaffeinated and organic coffee. The levels of amines varied among lots of the same brand and among brands. The color characteristics varied among types of instant coffee. The pH of the beverage varied from 4.86 to 5.15, with higher levels in decaffeinated coffee. There was significant positive correlation between pH and the levels of tyramine and agmatine. Investigations are needed to ascertain the impact of these amines on coffee flavor and on human health, and to determine the factors which affect amine formation and accumulation in instant coffee.
Source : J Food Comp Anal 2007 vol.20(6), pp 451 - 457
Correlation of selected constituents with the total antioxidant capacity of coffee beverages: influence of the brewing procedure
Lopez-Galilea, I.; Pena, M. P.; Cid, C.
Relationships between volatile and nonvolatile compounds and the antioxidant capacity of coffee brews prepared from commercial conventional and torrefacto roasted coffees, employing commonly used doses and prepared by four brewing procedures (filter, plunger, mocha, and espresso machine) were assessed. Significant correlations between volatile Maillard reaction products and antioxidant capacity (measured by both 2,2-diphenyl-1-picrylhydrazyl radical and redox potential methods) were not observed. Highly positive orrelations between browned compounds and caffeine with both antioxidant capacity parameters were reported. Principal component analysis allowed coffee brews separation according to coffee roasting processes (PC1) and brewing procedures (PC2), showing that in all cases coffee brews from torrefacto roasted coffee were more antioxidant that those extracted from conventional ones; also, coffee brews extracted by an espresso machine were more antioxidant than those extracted by mocha, plunger, and flter machines. Keywords: Coffee; antioxidants; torrefacto; brewing procedure.
Source : J Agric Food Chem 2007 vol.55 (15), pp 6110 - 6117
Modeling the effect of water activity and storage temperature on chemical stability of coffee brews
Manzocco, L.; Nicoli, M. C.
This work was addressed to study the chemical stability of coffee brew derivatives as a function of water activity (aw) and storage temperature. To this purpose, coffee brew was freeze-dried, equilibrated at increasing aw values, and stored for up to 10 months at different temperatures from -30 to 60 degrees C. The chemical stability of the samples was assessed by measuring H3O+ formation during storage. Independently of storage temperature, the rate of H3O+ formation was considerably low only when aw was reduced below 0.5 (94% w/w). Beyond this critical boundary, the rate increased, reaching a maximum value at ca. 0.8 aw (78% w/w). Further hydration up to the aw of the freshly prepared beverage significantly increased chemical stability. It was suggested that mechanisms other than lactones' hydrolysis, probably related to nonenzymatic browning pathways, could contribute to the observed increase in acidity during coffee staling. The temperature dependence of H3O+ formation was welldescribed by the Arrhenius equation in the entire aw range considered. However, aw affected the apparent activation energy and frequency factor. These effects were described by simple equations that were used to set up a modified Arrhenius equation. This model was validated by comparing experimental values, not used to generate the model, with those estimated by the model itself. The model allowed efficient prediction of the chemical stability of coffee derivatives on the basis of only the aw value and storage temperature.
Source : J Agric Food Chem 2007 vol.55 (16), pp 6521 - 6526
Effect of operating conditions on ochratoxin A extraction from roasted coffee
Mounjouenpou, P.; Durand, N.; Guyot, B.; Guiraud, J. P.
Operating conditions affect ochratoxin A (OTA) extraction from roasted coffee. The OTA content found in the beverage can thus be greater than that found in the roasted coffee used to prepare it. 3 extraction parameters were studied for roasted coffee: type of extraction solvent (alkaline, neutral, acid); temp. (23, 60 and 85°C); and extraction time (5, 20, 30, 40, 50, 60 and 80 min). The alkaline solvent used in the method recommended by the European Union was found to extract OTA best; however, a max. content was obtained at 60°C after 50 min. At least a 100% improvement in extraction was obtained when compared with the European Union usual quantification method that is carried out at ambient temp. It turned out that the OTA extraction parameters for roasted coffee, as defined by that method, were not optimum and needed to be modified. These results were verified in double-extraction experiments showing that OTA is not completely extracted by this method. Confirmation was obtained by comparison of extraction methods on several commercial samples of roasted coffee.
Souce : Food Addit Contam 2007 vol.24 (7), pp 730 - 734
Determination of acrylamide in coffee and chocolate by pressurised fluid extraction and liquid chromatography-tandem mass spectrometry
Pardo, O.; Yusa, V.; Coscolla, C.; Leon, N.; Pastor, A.
A selective and sensitive procedure was developed and validated for the determination of Acrylamide in difficult matrices, such as coffee and chocolate. The proposed method includes pressurized fluid extraction (PFE) with acetonitrile, florisil(R) clean-up purification inside the PFE extraction cell and detection by LC coupled to atmospheric pressure ionisation in positive mode tandem MS (APCI-MS-MS). Comparison of ionisation sources (atmospheric pressure chemical ionisation (APCI), atmospheric pressure photoionization (APPI) and combined APCl/APPI) and clean-up procedures were performed to improve the analytical signal. The main parameters affecting performance of the different ionisation sources were previously optimised using statistical design of experiments (DOE). PFE parameters were also optimised by DOE. For quantitation, an isotope dilution approach was used. The limit of quantification (LOQ) of the method was 1 mug/kg for coffee and 0.6 mug/kg for chocolate. Recoveries were in the ranges 81-105% in coffee and 87-102% in chocolate. Accuracy was evaluated using a coffee reference test material FAPA T3008. Using the optimised method, 20 coffee and 15 chocolate samples collected from Spanish supermarkets were investigated for acrylamide, yielding median levels of 146 mug/kg in coffee and 102 mug/kg in chocolate.
Source : Food Add Contam 2007 vol.24(7), pp 663 - 672
Mixture resolution according to the percentage of robusta variety in order to detect adulteration in roasted coffee by near infrared spectroscopy
Pizarro, C.; Esteban-Diez, I.; Gonzalez-Saiz, J. M.
Near infrared spectroscopy (NIRS), combined with multivariate calibration methods, has been used to quantify the robusta variety content of roasted coffee samples, as a means for controlling and avoiding coffee adulteration, which is a very important issue taking into account the great variability of the final sale price depending on coffee varietal origin. In pursuit of this aim, PLS regression and a wavelet-based preprocessing method that we have recently developed called OWAVEC were applied, in order to simultaneously operate two crucial pre-processing steps in multivariate calibration: signal correction and data compression. Several pre-processing methods (mean centering, first derivative and two orthogonal signal correction methods, OSC and DOSC) were additionally applied in order to find calibration models with as best a predictive ability as possible and to evaluate the performance of the OWAVEC method, comparing the respective quality of the different regression models constructed. The calibration model developed after pre-processing derivative spectra by OWAVEC provided high quality results (0.79% RMSEP), the percentage of robusta variety being predicted with a reliability notably better than that associated with the models constructed from raw spectra and also from data corrected by other orthogonal signal correction methods, and showing a higher model simplicity.
Source : Anal Chim Acta 2007 vol.585 (2), pp 266 - 276
Fresh coffee husks as potential sources of anthocyanins
Prata, E.-R. B. A.; Oliveira, L. S.
Fresh coffee husks, comprised of outer skin and pulp, were investigated as potential sources of anthocyanins for applications as natural food colorants. The extracted pigments were analysed by HPLC with photodiode array detection. Partial hydrolysis and analysis of the resulting fragments were helpful in the characterization procedure. Cyanidin 3-rutinoside was characterized as the dominant anthocyanin in fresh coffee husks and its quantification suggested the fresh coffee husks to be a good candidate as source of this pigment.
Source : LWT Food Sci Technol 2007 vol.40 (9), pp 1555 - 1560
Determination of phenolic acids in coffee by micellar electrokinetic chromatography
Risso, E. M.; Peres, R. G.; Amaya-Farfan, J.
A seven-minute micellar electrokinetic chromatography analytical procedure capable of resolving the five principal phenolic acids in coffee, including the isomers of 5-caffeoylquinic acid (5-CQA), 4-CQA and 3-CQA, caffeic acid and ferulic acid is reported. The electrophoretic conditions consisted of an SDS (70mM)-phosphate (17.6mM)-methanol (5% v/v) buffer system, pH 2.5, 22.1°C, -17 kV and detection at 325 nm. The Joule effect and the possible interactions between the buffer components and temperature with respect to peak quality, resolution and selectivity were assessed in the concentration range of 25-900 mug/mL. Performance evaluation of the system used a 33-7 factorial design at the 95% confidence level. The lowest correlation coefficient for linearity was 0.99888 for the 4-CQA. Limits of detection and quantification were 0.98 and 4 mug/mL. The method was tested with both green and roasted coffee beans using four systems of extraction.
Source : Food Chemistry 2007 vol.105(4), pp 1578 - 1582
A GC method for simultaneous analysis of bornesitol, other polyalcohols and sugars in coffee and its substitutes
Ruiz-Matute, A. I.; Montilla, A.; del Castillo, M. D.; Martinez-Castro, I.; Sanz, M. L.
A GC method has been developed for the determination of polyalcohols and sugars in aqueous extracts from green coffee beans, ground roasted coffee beans submitted to either conventional or torrefacto processes, coffee blends and soluble instant coffees. Bornesitol was detected in aqueous coffee extracts for the first time. Mannitol, myo-inositol, mannose, fructose, galactose, glucose and sucrose have also been determined. Results seem to indicate that coffee manufacturing processes, such as roasting or decaffeination, do not affect the polyalcohol content. Coffee substitutes based on cereals, carob or chicory, have also been studied. The possibility to characterize their presence in coffee extracts was evaluated.
Source : J Sep Sci 2007 vol.30 (4), pp 557 - 562
Discrimination among different brands of coffee by using vis-near infrared spectra
Wang, Y. Y.; He, Y.; Shao, Y. N.; Zhang, Z. F.
Near infrared spectroscopy technology was used to distinguish three different brands of coffee bought from the supermarket. Two models, PCA-BP and WT-BP, were employed for the analysis and prediction of the samples. The discrimination among the different brands of coffee was based on the combination of the function of data compression in the PCA and WT technology and the ability of learning and prediction of the artificial neural network. In the experiment, 60 samples were used for model calibration and 30 for brand prediction. The result showed that both the PCA-BP and WT-BP models achieved 100% discrimination rate, and the wavelet transforms technology is superior to the principal component analysis both in time-consuming and the capability of data compression. It is indicated that the model set up by the combination of WT technology and BP neural network in the present study is rapid in analysis and precise in pattern discrimination. It can be concluded that a new approach to distinguishing pure coffee was of fered and the result of this experiment established the foundation for the determination of the raw material (coffee bean) of different brands of coffee in the market.
Source : Guang Pu Xue Yu Guang Pu Fen Xi 2007 vol.27 (4), pp 702 - 706 (not available on line)
Formation and reduction of acrylamide in Maillard reaction: a review based on the current state of knowledge
Yu, Zhang; Ying, Zhang
Current knowledge regarding formation and reduction of acrylamide during the Maillard reaction is discussed. Aspects considered include: fundamental mechanistic studies; importance of asparagine and sugars in the Maillard reaction; acrylamide formation studies in different food matrices (potatoes, bread and other cereal products, almonds, coffee); kinetic studies on acrylamide formation; mechanistic studies on the reduction of acrylamide; effects of raw materials and processing on acrylamide levels (limiting levels of reducing sugars, modifying processing conditions, changing heat processing methods); use of additives to inhibit acrylamide formation (citric acid, proteins and their hydrolysates, hydrogencarbonates); effect of cooking on acrylamide formation; and mitigation studies performed using the CIAA toolbox approach.
Source : Critic Rev Food Sci Nutr 2007 vol.47(5), pp 521 - 542
Marangoni effect reverses coffee-ring depositions
Hu, H.; Larson, R. G.
We show here both experimentally and theoretically that the formation of "coffee-ring" deposits observed at the edge of drying water droplets requires not only a pinned contact line but also suppression of Marangoni flow. For simple organic fluids, deposition actually occurs preferentially at the center of the droplet, due to a recirculatory flow driven by surface-tension gradients produced by the latent heat of evaporation. The manipulation of this Marangoni flow in a drying droplet should allow one in principle to control and redirect evaporation-driven deposition and assembly of colloids and other materials .
Source : J Phys Chem B 2006 vol.110 (14), pp 7090 - 7094
Report of the 1st session of the Codex Committee on Contaminants in Foods
Anon.
Minutes of the 1st session of the Codex Committee on Contaminants in Foods, held in Beijing, China,
on 16-20 April 2007, are reported. Agenda items discussed include: matters arising from meetings of
Codex Alimentarius Commission, Codex committees and task forces, FAO, WHO and the 67th session of the Joint FAO/WHO Expert Committee on Food Additives (JECFA); revision of the preamble to the Codex
General Standard for contaminants and toxins in foods and an amendment of schedule 1 of this standard; draft MRL for ochratoxin A in wheat, barley and rye; aflatoxins in almonds, hazelnuts, pistachio nuts and Brazil nuts (discussion papers, draft MRL, sampling plan); a draft code of practice for prevention and reduction of ochratoxin contamination in wines; draft MRL for tin in canned foods and beverages; draft MRL for 3-monochloropropane-1, 2-diol (MCPD) in liquid condiments containing acid-hydrolysed vegetable proteins (excluding naturally-fermented soy sauces) and a draft code of practice for reducing MCPD contamination during production of these condiments; a draft code of practice for reduction of acrylamide in food; a draft code of practice for reducing contamination of food with PAH from smoking and
direct drying; discussion papers on ochratoxin A in coffee and cocoa, aflatoxin in dried figs, and deoxynivalenol; and a priority list of contaminants and naturally occurring toxicants proposed for evaluation by JECFA. 14 appendices are included comprising a list of participants, various documents under discussion in the session and the reply to a question arising from the 27th session of the Codex committee on Methods of Analysis and Sampling relating to dioxins and PCB in foods. [This report was
prepared for the 30th session of the Codex Alimentarius Commission (Joint FAO/WHO Food Standards Programme), 2-7 July 2007 in Rome, Italy. It is available from the Codex Alimentarius website in En, Es or
Fr.]
Source : Report of the 1st session of the Codex Committee on Contaminants in Foods (2007)
Differentiation of coffee varieties according to their sterolic profile
Cizkova, H.; Soukupova, V.; Voldrich, M.; Sevick, R.
Possibility for differentiating arabica and robusta coffees on the basis of their sterol fractions was studied. 14 commercial roasted coffee samples and 13 model samples of known origin (6 arabica, 4 robusta and 3 arabica/robusta blends) were analysed for sterols profiles by GC-MS following hexane extraction, lipid saponification and conversion of sterols to trimethyl silyl derivatives. Several statistical approaches, including multilinear regression, principal component analysis and cluster analysis, were used for differentiation between arabica and robusta in model samples. Main sterols identified in model and commercial coffees were campesterol, stigmasterol, sitosterol, DELTA5-avenasterol and stigmastenol. A correlation equation was developed for prediction of arabica content of coffee from percentage DELTA5-avenasterol in total sterols, with a high correlation coeff. (R2 = 0.98) and precision (relative s.d. = 7.9%). When applied to determination of arabica/robusta composition of commercial samples, coffees labelled as arabica were found to be authentic.
Source : J Food Nutr Res 2007 vol.46(1), pp 28 - 34 (not available on line)
COFFEE & HEALTH
Chlorogenic acid compounds from coffee are differently absorbed and metabolised in humans
M. Monteiro, A. Farah, D. Perrone, L. C. Trugo, C. Donangelo
Chlorogenic acids (CGA) are abundant phenolic compounds in coffee, with caffeoylquinic (CQA), feruloylquinic (FQA), and dicaffeoylquinic (diCQA) acids being the major subclasses. Despite the potential biopharmacological properties attributed to these compounds, little is known about their bioavailability in humans. In this study, we evaluated the distribution profile of the major CGA isomers and metabolites in plasma and urine of 6 healthy adults for 4 h after brewed coffee consumption. Three CQA isomers and 3 diCQA isomers were identified in the plasma of all subjects after coffee consumption, whereas 2 FQA were identified in only 1 subject. Two plasma concentration peaks were observed, the first at 0.5–1.0 h
and the second at 1.5–4.0 h after coffee consumption. The molar ratio CQA:diCQA was 12.2 in the brewed coffee, whereas in plasma it ranged from 0.6–2.9. The molar ratios 5-CQA:3-CQA and 5-CQA:4-CQA were consistently higher in plasma than in the brew. The main CGA metabolites identified in urine after coffee consumption were: dihydrocaffeic, gallic, isoferulic, ferulic, vanillic, caffeic, 5-CQA, sinapic, r-hydroxybenzoic, and r-coumaric acids (gallic and dihydrocaffeic acids being the major ones). This study indicates that the major CGA compounds present in coffee are differentially absorbed and/or metabolized in humans, with a large inter-individual variation. Moreover, urine does not appear to be a major excretion pathway of intact CGA compounds in humans.
Source : J. Nutr. 2007 vol.137, pp 2196–2201, 2007
Effects of different substance misuse in genital reflexes of paradoxical sleep deprived male rats
Andersen, M. L.; Perry, J. C.; Papale, L. A.; Tufik, S.
As psychostimulants are widely abused, their neurochemical and behavioral effects have been extensively studied for many years. Our previous data demonstrate that paradoxical sleep deprivation (PSD) enhances drug-induced penile erection and ejaculation. PSD in association to drugs of abuse like cocaine potentiated genital reflexes in male rats. In this sense, the present study investigated if three substances abused by young people--such as Delta(9)-tetrahydrocannabinol (Delta(9)THC), alcohol and caffeine--had any significant effect on the genital reflexes in PSD rats. The results indicated that PSD induced erection in 50% of the rats and 20% ejaculated. In addition, there was no significant alteration in the number of animals exhibiting genital reflexes neither on the frequency of these behaviors when challenged with Delta(9)-THC or alcohol or caffeine after 96 h of PSD. These findings show that Delta(9)THC, alcohol and caffeine when administrated isolated did not produce alterations in genital reflexes in the PSD male rats.
Source : Scand J Psychol 2007 vol.48 (3), pp 191 - 195
Caffeine, fluid-electrolyte balance, temperature regulation, and exercise-heat tolerance
Armstrong, L. E.; Casa, D. J.; Maresh, C. M.; Ganio, M. S.
Dietitians, exercise physiologists, athletic trainers, and other sports medicine personnel commonly recommend that exercising adults and athletes refrain from caffeine use because it is a diuretic, and it may exacerbate dehydration and hyperthermia. This review, contrary to popular beliefs, proposes that caffeine consumption does not result in the following: (a) water-electrolyte imbalances or hyperthermia and (b) reduced exercise-heat tolerance.
Source : Exerc Sport Sci Rev 2007 vol.35 (3), pp 135 - 140
Dietary factors and fertility in women of childbearing age
Derbyshire, E.
In view of a reported decrease in fertility rates in British women, studies on the role of dietary factors in female fertility are reviewed. Effects of alcohol, antioxidants, caffeine and trace elements, such as zinc, are considered. Studies suggest that alcohol and caffeine consumption may reduce the likelihood of successful conception. There is a need for randomised control trials to investigate the effects of antioxidants and micronutrients.
Source : Nutr Food Sci 2007 vol.37 (2), pp 100-104
Effect of nicotine and ephedrine on the accumulation of 18F-FDG in brown adipose tissue
Baba, S.; Tatsumi, M.; Ishimori, T.; Lilien, D. L.; Engles, J. M.; Wahl, R. L.
This study evaluated the effect of various beta-adrenergic agonists on (18)F-FDG uptake in brown adipose tissue (BAT) in rats using ex vivo biodistribution studies. METHODS: Caffeine (10 mg/kg of body weight, n = 4), ephedrine (5 mg/kg of body weight, n = 4), nicotine (0.8 mg/kg of body weight, n = 9), or a mixture of nicotine and ephedrine (0.8 mg/kg of body weight and 5 mg/kg of body weight, respectively, n = 9) was injected into the peritoneal cavity of female Lewis rats 30 min before intravenous (18)F-FDG injection. One hour after injection of (18)F-FDG, the animals were sacrificed, and BAT, other major organs, and blood were extracted. The biodistribution results were compared with body temperature data. RESULTS: In the rats injected with nicotine or ephedrine, the mean uptake of (18)F-FDG, in percentage injected dose (%ID)/(g of interscapular BAT) x (kg of body weight), was significantly increased (7.9-fold for nicotine and 3.7-fold for ephedrine), compared to the control rats. Nicotine had the strongest effect on (18)F-FDG uptake in BAT. Caffeine increased BAT uptake slightly, but this increase did not reach statistical significance. The combination of nicotine and ephedrine increased the uptake 12.0-fold, compared with control rats; more than either nicotine or ephedrine alone. Uptake of (18)F-FDG in most other major organs did not change significantly. The effect of nicotine was blocked by prior injection of beta-adrenergic antagonists. A transient decrease in body temperature was observed in the nicotineinjected group, and this effect was canceled by prior injection of beta-adrenergic antagonists. No significant change in baseline temperature was seen before or after beta-adrenergic agonist injection.
CONCLUSION: Nicotine caused a greater increase in (18)F-FDG uptake in BAT than did other interventions, and the effect was increased when nicotine was combined with ephedrine. The effect of nicotine was completely blocked by prior injection of beta-adrenergic antagonists, indicating that betaadrenergic agonists increase the metabolism of BAT. These preclinical data suggest that patients should avoid nicotine and ephedrine before undergoing (18)F-FDG PET to minimize (18)F-FDG uptake in BAT.
Source : J Nucl Med 2007 vol.48 (6), pp 981 - 986
Effect of Ilex extracts and isolated compounds on peroxidase secretion of rat submandibulary glands
Filip, R.; Sebastian, T.; Ferraro, G.; Anesini, C.
The presence of polyphenolic compounds and flavonoids in Ilex paraguariensis make its extracts, including Yerba Mate (an infusion drank in south America), potential free-radical scavengers (if they are not destroyed during processing). This study showed that administration of aqueous extracts of Ilex paraguariensis and Yerba Mate increased peroxidase secretion in rat submandibular glands, and total peroxidase activity (EC50: Yerba Mate: 148 mg/litre; Ilex paraguariensis: 841 mg/litre). This activity is attributed to the caffeine and chlorogenic acid present in the extracts, at levels of 0.7-1.0% and 2.0-2.8% of the dried extracts, respectively.
Source : Food Chem Tox 2007 vol.45 (4), pp 649-655
Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions * COMMENTARY
Bassini-Cameron, A.; Sweet, E.; Bottino, A.; Bittar, C.; Veiga, C.; Cameron, L. C.; Dantas, E. H.
To evaluate the effect of caffeine on white cell distribution and muscle injury markers in professional soccer players during exercise. METHODS: 22 male athletes completed a placebo controlled double blind test protocol to simulate a soccer match, followed by a Yo-Yo intermittent recovery test. RESULTS: Exercise caused an increase in packed cell volume that was enhanced by caffeine. Caffeine and exercise had a synergistic effect on the blood lymphocyte count, which increased by about 38% after exercise, and by an additional 35% when combined with caffeine. Caffeine promoted an exercise independent rise in circulating monocytes, and a synergistic action of exercise and caffeine was observed on segmented neutrophils. Caffeine promoted thrombocytosis. Plasma adenosine deaminase, aspartate aminotransferase, and lactate dehydrogenase concentrations were enhanced by exercise, and alanine transaminase concentration was enhanced in both groups, with a synergistic effect of caffeine.
CONCLUSIONS: The pronounced increase in the white cell count in the group receiving caffeine appeared to be caused by greater muscle stress and consequently more intense endothelial and muscle cell injury. The use of caffeine may augment the risk of muscle damage in athletes.
Source : Br J Sports Med 2007 vol.41 (8), pp 523 - 530 and Commentaries
Caffeine attenuates practice effects in word stem completion as measured by fMRI BOLD signal
Bendlin, B. B.; Trouard, T. P.; Ryan, L.
Caffeine ingestion results in increased brain cell metabolism (Nehlig et al. [1992] Brain Res Brain Res Rev 17:139-170) and decreased cerebral blood flow (Field et al. [2003] Radiology 227:129-135; Mulderink et al. [2002] Neuroimage 15:37-44). The current study investigated the effect of caffeine in a word stem completion task using only novel word stems (no repeated stimuli). Resting perfusion was measured with arterial spin labeled perfusion MRI, along with blood oxygenation level-dependent (BOLD) signal before and after ingestion of regular coffee, decaffeinated coffee, and water. Based on previous research (Laurienti et al. [2002] Neuroimage 17:751-757; Mulderink et al. [2002] Neuroimage 15:37-44), we hypothesized that caffeine would result in increased BOLD signal intensity and extent of BOLD activation. As expected, caffeine resulted in a significant decrease in cerebral perfusion. However, both the control and caffeine groups showed an increase in BOLD signal amplitude across two sets of novel word stems. Additionally, the control group showed a 50% reduction in the extent of BOLD activation, while the caffeine group showed no change in activation extent. Neither group showed changes in BOLD baseline signal over time, which had been suggested to mediate caffeine-related BOLD signal changes. The results suggest that caffeine may attenuate general task practice effects that have been described in recent functional MRI studies of word stem completion.
Source : Hum Brain Mapp 2007 vol.28 (7), pp 654 - 662
Coffee, stress and cortisol in nursing staff
Harris, A.; Ursin, H.; Murison, R.; Eriksen, H. R.
According to cognitive activation theory, long-lasting work demands without rest or lack of coping may lead to sustained activation and pathology. Cortisol is one of the most important stress hormones in humans and increased basal levels of cortisol are considered a valid marker for sustained activation. In order to investigate this association further, we investigate the relationships between salivary cortisol profiles, job stress, work load (effort/reward, demand/control) and health (subjective health complaints and health-related quality of life) in a population of health care workers. Forty-four women filled in a questionnaire and collected five saliva samples on two consecutive working days (1: wake-up time, 2: wake-up time+30 min, 3: wake-up time+45 min, 4: 1500 h and 5: 2200 h). There was no relationship between psychosocial factors at work and cortisol levels in the morning (cortisol level at wake-up time and awakening cortisol response (ACR)). Only the confounding variable tobacco reached a significant level in the hierarchical regressions analyses. Our significant findings are limited to the afternoon decline and the evening values. The decrease during the day relates to decision authority, physical functioning, general health, and vitality in the single, unadjusted regression analyses. The decrease also relates to coffee intake, which we included originally as a confounding variable. In the final hierarchical regression of the evening values, only decision authority and coffee were significantly related to cortisol levels in the evening.
Source : Psychoneuroendocrinology 2007 vol.32 (4), pp 322 - 330
Effects of repeated doses of caffeine on performance and alertness: new data and secondary analyses
Hewlett, P.; Smith, A.
The effects of caffeine on mood and performance are well established. Some authors suggest that caffeine merely reverses effects of caffeine withdrawal rather than having direct behavioural effects. It has also been suggested that withdrawal may be removed by a first dose of caffeine and further doses have little subsequent effect. These issues are examined here. OBJECTIVES: The present study aimed to determine whether caffeine withdrawal influenced mood and performance by comparing regular consumers who had been withdrawn from caffeine overnight with non-consumers. Following this repeated caffeine doses were administered to test the claim that repeated dosing has no extra effect on mood or performance. Secondary analyses of data collected after a day of normal caffeine consumption were also carried out to examine some alternative explanations of their results which showed effects of caffeine after a day of normal caffeine consumption. METHODS: One hundred and twenty volunteers participated in the study. Regular caffeine consumption was assessed by questionnaire and this showed that 36 of the volunteers did not regularly consume caffeinated beverages. Volunteers were instructed to abstain from caffeine overnight and then completed a baseline session measuring mood and a range of cognitive functions at 08.00 the next day. Following this volunteers were given 0, or 1 mg/kg caffeine in a milkshake, glucose solution or water (at 09:00), followed by a second 0 or 1 mg/kg caffeine dose (at 09:40) and the test battery repeated at 10:00. RESULTS: The baseline data showed no effect of overnight caffeine withdrawal on mood or performance. In contrast, caffeine challenge improved vigilance performance and prevented decreases in alertness induced by completion of the task battery. The magnitude of these effects increased as a function of the number of doses of caffeine given. Secondary analyses of data from Christopher et al. (2003) also confirmed that effects of caffeine did not depend on length of withdrawal.
CONCLUSIONS: The present findings show no effect of overnight caffeine withdrawal on mood and performance. Caffeine challenge did have the predicted effect on alertness and vigilance, with the size of the effects increasing with caffeine dose. These findings suggest that the effects of caffeine are not due to reversal of effects of withdrawal, a view confirmed by secondary analyses of data collected after a day of normal caffeine consumption.
Source : Hum Psychopharmacol 2007 vol.22 (6), pp 339 - 350
Coffee consumption protects human lymphocytes against oxidative and 3-amino-1-methyl-5H-pyrido[4,3-b]indole acetate (Trp-P-2) induced DNA-damage: Results of an experimental study with human volunteers
Bichler, J.; Cavin, C.; Simic, T.; Chakraborty, A.; Ferk, F.; Hoelzl, C.; Schulte-Hermann, R.; Kundi, M.;
Haidinger, G.; Angelis, K.; Knasmuller, S.
Aim of the study was to investigate the impact of coffee on DNA-stability in humans. DNA-damage was monitored in lymphocytes of eight individuals with single cell gel electrophoresis assays before and after consumption of 600 ml coffee (400ml paper filtered and 200ml metal filtered/d) for five days. Under standard conditions, no alteration of DNA-migration was seen, but a strong reduction of DNA-migration attributable to endogenous formation of oxidised purines and pyrimidines was detected with restriction enzymes; furthermore DNA-damage caused by reactive oxygen radicals (H2O2 treatment) and by the heterocyclic aromatic amine 3-amino-1-methyl-5H-pyrido[4,3-b]indole-acetate was significantly reduced after coffee consumption by 17% and 35%, respectively. Also in in vitro experiments, inhibition of H2O2 induced DNA-damage was observed with coffee at low concentrations (<less than or equal to>25mul/ml) whereas the diterpenoids cafestol and kahweol caused only marginal effects indicating that the effects of coffee are due to scavenging effects of other constituents. Enzyme measurements showed that additionally induction of antioxidant enzymes may play a role: while the activity of glutathione peroxidise was only marginally increased after coffee consumption, a significant (38%) increase of superoxide dismutase activity was detected. Comparisons with results of earlier studies suggest that coffee consumption may prevent oxidative DNA-damage to a higher extent as diets enriched in fruits and vegetables.
Source : Food Chem Toxicol 2007 vol.45(8), pp 1428 - 1436
Urinary acrylamide metabolites as biomarkers for short-term dietary exposure to acrylamide
Bjellaas, T.; Stolen, L. H.; Haugen, M.; Paulsen, J. E.; Alexander, J.; Lundanes, E.; Becher, G.
Acrylamide is a carcinogenic contaminant that may be produced when certain starch-rich foods are cooked at high temperature. Reliable biomarkers would be useful to monitor consumer dietary exposure to acrylamide. Acrylamide is mainly excreted in the urine as mercapturic acid derivatives. This work describes the use of HPLC with electrospray ionisation tandem mass spectrometry for the determination of acrylamide metabolites in the urine and how these levels correlated with acrylamide intake. The median dietary exposure to acrylamide was estimated to be 0.47 mcg/kg body weight per day. Urinary excretion of acrylamide metabolites was positively-associated with consumption of aspartic acid, protein, starch and coffee and negatively-associated with consumption of citrus fruits.
Source : Food Chem Toxicol 2007 vol.45 (6), pp 1020-1026
The effect of caffeine on dilated cerebral circulation and on diagnostic CO2 reactivity testing
Blaha, M.; Benes, V.; Douville, C. M.; Newell, D. W.
Reduction of cerebral blood flow by caffeine has been shown in multiple studies. However, the effect of this substance on pathologically dilated cerebral vessels is not clearly defined. The aim of this study was to investigate the effect of caffeine on an already dilated cerebral circulation and specify if these vessels are still able to constrict as a consequence of caffeine stimulation. A second aim of this study was to compare results of cerebral vasomotor CO(2) reactivity testing with and without caffeine ingestion. Seventeen healthy adult volunteers had vasomotor reactivity tested before and thirty minutes after ingestion of 300 mg of caffeine. Each vasomotor reactivity test consisted of velocity measurements from both middle cerebral arteries using transcranial Doppler ultrasound during normocapnia, hypercapnia, and hypocapnia. Hemodynamic data and end-tidal CO(2) (etCO(2)) concentration were also recorded. The vasomotor reactivity (VMR) and CO(2) reactivity were calculated from a measured data pool. At a level of etCO(2)=40 mmHg the resting velocity in the middle cerebral artery (V(MCA)) dropped from 70.7+/-22.8 cm/sec to 60.7 +/- 15.4 cm/sec 30 minutes after caffeine stimulation (14.1% decrease, p<0.001). During hypercapnia of etCO(2)=50 mmHg there was also a significant decline of V(MCA) from 103.1+/-25.4 to 91.4+/-21.8 cm/sec (11.3%, p<0.001). There was not a statistically significant reduction of V(MCA) during hypocapnia. Calculated VMR and CO(2) reactivity before and after caffeine intake were not statistically significant. The presented data demonstrate a significant decrease in cerebral blood flow velocities after caffeine ingestion both in a normal cerebrovascular bed and under conditions of peripheral cerebrovascular vasodilatation. These findings support the important role of caffeine in regulation of CBF under different pathological conditions. Despite significant reactive vasodilatation in the brain microcirculation, caffeine is still able to act as a competitive antagonist of CO(2) on cerebral microvessels. The fact that caffeine may decrease CBF despite significant pathological vasodilatation offers the possibility of therapeutic manipulation in patients with traumatic vasoparalysis. For routine clinical testing of CO(2) reactivity it is not necessary to insist on pre-test dietary restrictions.
Source : J Clin Neurosci 2007 vol.14 (5), pp 464 - 467
Caffeine and the kidney: what evidence right now?
Bolignano, D.; Coppolino, G.; Barilla, A.; Campo, S.; Criseo, M.; Tripodo, D.; Buemi, M.
Caffeine, or 1, 3, 7-trimethylxanthine, is one of the most frequently consumed active drugs worldwide. Its main mechanisms of action include inhibiting the phosphodiesteratic enzyme and adenosine receptors and activating the ryanodine receptors with several actions on all organs. What effect does caffeine have on the kidney? Is caffeine beneficial or dangerous? A review of the current literature reveals conflicting opinions regarding the prolithiasic effect of this substance, whereas its diuretic action is least disputed and more easily observed. Caffeine may have a toxic or preventive effect in some physiologic or pathologic conditions. Some of these incongruences may depend on several factors, such as dosage, prior chronic exposure, genetic-enzymatic axes, and concomitant drug consumption. While awaiting further insight from forthcoming studies on the issue, we may reach a preliminary conclusion that, as yet, there is no evidence contraindicating the consumption of the equivalent of 3 to 4 cups of coffee per day in healthy or nephropathic subjects. However, particular attention should be paid to the elderly, children, and patients on concomitant treatment with analgesics or diuretics, whereas in subjects with a family or clinical history of calcium lithiasis a moderate caffeine consumption should be associated with an adequate fluid intake. Further in-depth studies are required to investigate whether this beverage is beneficial to patients on hemodialysis.
Source : J Ren Nutr 2007 vol.17 (4), pp 225 - 234
Evidence that a Ca(2+) sparks/STOCs coupling mechanism is responsible for the inhibitory effect of caffeine on electro-mechanical coupling in guinea pig ureteric smooth muscle
Borisova, L.; Shmygol, A.; Wray, S.; Burdyga, T.
Recent studies have highlighted the role of the sarcoplasmic reticulum (SR) in controlling excitability, Ca(2+) signalling and contractility in smooth muscle. Caffeine, an agonist of ryanodine receptors (RyRs) on the SR has been previously shown to effect Ca(2+) signalling but its effects on excitability and contractility are not so clear. We have studied the effects of low concentration of caffeine (1mM) on Ca(2+) signalling, action potential and contractility of guinea pig ureteric smooth muscle. Caffeine produced reversible inhibition of the action potentials, Ca(2+) transients and phasic contractions evoked by electrical stimulation. It had no effect on the inward Ca(2+) current or Ca(2+) transient but increased the amplitude and the frequency of spontaneous transient outward currents (STOCs) in voltage clamped ureteric myocytes, suggesting Ca(2+)-activated K(+) channels (BK) are affected by it. In isolated cells and cells in situ caffeine produced an increase in the frequency and the amplitude of Ca(2+) sparks as well the number of spark discharging sites per cell. Inhibition of Ca(2+) sparks by ryanodine (50muM) or SR Ca(2+)-ATPase (SERCA) cyclopiazonic acid (CPA, 20muM) or BK(Ca) channels by iberiotoxin (200nM) or TEA (1mM), fully reversed the inhibitory effect of caffeine on Ca(2+) transients and force evoked by electrical field stimulation (EFS). These data suggest that the inhibitory effect of caffeine on the action potential, Ca(2+) transients and force in ureteric smooth muscle is caused by activation of Ca(2+) sparks/STOCs coupling mechanism.
Source : Cell Calcium 2007 vol.42 (3), pp 303 - 311
Caffeine use by children: the quest for enhancement
Bramstedt, K. A.
Fair play, both in academics and sports, is a concept that is challenged by the notion of performance enhancement. Both cognitive and physical performance can be viewed as potentially enhanceable, and arguments can be made that enhancement can serve two purposes: gaining an edge or keeping up with others (who may or may not have used performance-enhancing substances). Caffeine, a central nervous system and cardiac stimulant, is frequently used by children for both academic and athletic performance enhancement. In fact, the marketplace contains a plethora of caffeinated products marketed directly to children. This article examines safety and ethical issues associated with the use of caffeine by children and explores the question: Can cognitive performance enhancement be ethically permissible if sports performance enhancement is not?
Source : Subst Use Misuse 2007 vol.42 (8), pp 1237 - 1251
Coffee drinking and hepatocellular carcinoma risk: a meta-analysis
Bravi, F.; Bosetti, C.; Tavani, A.; Bagnardi, V.; Gallus, S.; Negri, E.; Franceschi, S.; La Vecchia, C.Several studies suggest an inverse relation between coffee drinking and risk of hepatocellular carcinoma (HCC). We conducted a meta-analysis of published studies on HCC that included quantitative information on coffee consumption. Ten studies were retrieved (2,260 HCC cases), including 6 case-control studies from southern Europe and Japan (1551 cases) and 4 cohort studies from Japan (709 cases). The summary relative risk (RR) for coffee drinkers versus non-drinkers was 0.54 (95% confidence interval [CI] 0.38-0.76) for case-control studies and 0.64 (95% CI 0.56-0.74) for cohort studies. The overall RR was 0.59 (95% CI 0.49-0.72), with significant heterogeneity between studies. The overall summary RR for low or moderate coffee drinkers was 0.70 (95% CI 0.57-0.85), and that for high drinkers was 0.45 (95% CI 0.38-0.53). The summary RR for an increase of 1 cup of coffee per day was 0.77 (95% CI 0.72-0.83) from case-control studies, 0.75 (95% CI 0.65-0.85) from cohort studies, and 0.77 (95% CI 0.72-0.82) overall. The consistency of an inverse relation between coffee drinking and HCC across study design and geographic areas weighs against a major role of bias or confounding. Coffee drinking has also been related to reduced risk of other liver diseases, thus suggesting a continuum of the favorable effect of coffee on liver function. However, subjects with liver conditions may selectively reduce their coffee consumption. CONCLUSION: The present analysis provides evidence that the inverse relation between coffee and HCC is real, though inference on causality remains open to discussion.
Source : Hepatology 2007 vol.46 (2), pp 430 - 435
Maternal caffeine consumption and risk of cardiovascular malformations
Browne, M. L.; Bell, E. M.; Druschel, C. M.; Gensburg, L. J.; Mitchell, A. A.; Lin, A. E.; Romitti, P. A.; Correa, A.
The physiologic effects and common use of caffeine during pregnancy call for examination of maternal caffeine consumption and risk of birth defects. Epidemiologic studies have yielded mixed results, but such studies have grouped etiologically different defects and have not evaluated effect modification. METHODS:: The large sample size and precise case classification of the National Birth Defects Prevention Study allowed us to examine caffeine consumption and specific cardiovascular malformation (CVM) case groups. We studied consumption of caffeinated coffee, tea, soda, and chocolate to estimate total caffeine intake and separately examined exposure to each caffeinated beverage. Smoking, alcohol, vasoactive medications, folic acid supplement use, and infant gender were evaluated for effect modification. Maternal interview reports for 4,196 CVM case infants overall and 3,957 control infants were analyzed. RESULTS:: We did not identify any significant positive associations between maternal caffeine consumption and CVMs. For tetralogy of Fallot, non significant elevations in risk were observed for moderate (but not high) caffeine intake overall and among nonsmokers (ORs of 1.3 to 1.5). Risk estimates for both smoking and consuming caffeine were less than the sum of the excess risks for each exposure. We observed an inverse trend between coffee intake and risk of atrial septal defect; however, this single significant pattern of association might have been a chance finding.
CONCLUSIONS:: Our study found no evidence for an appreciable teratogenic effect of caffeine with regard to CVMs.
Source : Birth Defects Res A Clin Mol Teratol 2007 vol.79 (7), pp 533 - 543
Coffee consumption and risk of type 2 diabetes and heart disease
Campos, H.; Baylin, A.
Coffee consumption is reported to be potentially protective against the development of type-2 diabetes, but with possible adverse cardiovascular effects, recommendations for optimal coffee intake are difficult to establish. This paper considers studies examining coffee consumption and cardiovascular disease (CVD) risk, genetic predisposition to the adverse effects of coffee, and coffee consumption and biomarkers of CVD risk. Studies examining reduced risk of type-2 diabetes with coffee consumption, and the possible protective mechanism of coffee consumption on type-2 diabetes are also discussed.
Source : Nutrition Reviews 2007 vol.65 (4), pp 173-179
Comparison of white tea, green tea, epigallocatechin-3-gallate, and caffeine as inhibitors of PhIP-induced colonic aberrant crypts
Carter, O.; Dashwood, R. H.; Rong, Wang; Dashwood, W. M.; Orner, G. A.; Fischer, K. A.; Lohr, C. V.;
Pereira, C. B.; Bailey, G. S.; Williams, D. E.
There is growing interest in the possible health benefits of tea. The inhibition by white tea of 2-amino-
1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced colonic aberrant crypt foci (ACF) in the rat has
been previously reported. To distinguish between blocking and suppressing effects, and thus provide
mechanistic insights into prevention during the initiation vs. post-initiation phases of carcinogenesis, white tea and green tea were administered at 2% (w/v) as the sole source of drinking fluid either 2 wk before and 2 wk during PhIP dosing (100 mg/kg, every other day by oral gavage), or starting 1 wk after the
carcinogen and continued until the study was terminated at 16 wk. In the former protocol, each tea
produced marginal inhibition of colonic ACF, despite evidence for changes in several hepatic enzymes
involved in heterocyclic amine metabolism. However, post-initiation the data were as follows (ACF/colon,
mean ± SE): PhIP/water 12.2 ± 1.5; PhIP/white tea 5.9 ± 0.9 (P < 0.01); PhIP/caffeine 5.9 ± 1.5 (P <
0.01); PhIP/EGCG 3.5 ± 0.8 (P < 0.001); PhIP/green tea 8.9 ± 1.2 (P = 0.22, not significant). In the latter
study, apoptosis was determined using in situ oligo ligation and cleaved caspase-3 assays, whereas cell
proliferation was assessed via bromodeoxyuridine (BrdU) incorporation. No consistent changes were seen in apoptosis assays, but BrdU labelling was as follows (percent of cells positive/colonic crypt, mean ± s.e.): PhIP/water 10.4 ± 0.6; PhIP/white tea 8.6 ± 0.2 (P < 0.05); PhIP/EGCG 6.0 ± 0.85 (P < 0.01);
PhIP/caffeine 8.75 ± 0.45 (P < 0.05); and PhIP/green tea 9.5 ± 0.4 (P > 0.05, not significant). The data
imply that white tea, caffeine and EGCG may be most effective post-initiation, via the inhibition of cell
proliferation in the colon and through the suppression of early lesions.
Source : Nutrition and Cancer 2007 vol.58(1), pp 60 - 65
The effects of caffeine on the preterm sheep ductus arteriosus
Clyman, R. I.; Roman, C.
Caffeine and other methyl xanthines are widely used in the neonatal period. A recent, randomized, placebo-controlled, multicenter trial found that infants who were randomly assigned to caffeine treatment had less need for pharmacologic and/or surgical closure of a patent ductus arteriosus (PDA). We hypothesized that the decreased need for pharmacologic and surgical closure of the PDA after caffeine treatment might be due to a direct effect of caffeine on ductus contractility. We examined preterm fetal lamb ductus arteriosus (from 24 fetuses, 105 +/- 4 d of gestation, term = 147 d), in vitro to determine the direct effects of caffeine on the isometric tension of the ductus arteriosus. Caffeine (0.003-0.3 mM) had no direct effect on ductus arteriosus tension, nor did it affect the contractile response of the ductus arteriosus to increasing oxygen concentrations. Caffeine's lack of effect was observed in both the presence and absence of indomethacin and NG-nitro-L-arginine methyl ester (L-NAME) (inhibitors of prostaglandin and nitric oxide production). In conclusion, we found no evidence of a direct effect of therapeutic caffeine concentrations on ductus contractility.
Source : Pediatr Res 2007 vol.62 (2), pp 167 - 169
Genetic polymorphism of the adenosine A2A receptor is associated with habitual caffeine consumption
Cornelis, M. C.; El Sohemy, A.; Campos, H.
Caffeine is the most widely consumed stimulant in the world, and individual differences in response to its stimulating effects may explain some of the variability in caffeine consumption within a population. OBJECTIVE: We examined whether genetic variability in caffeine metabolism [cytochrome P450 1A2 (CYP1A2) -163A-->C] or the main target of caffeine action in the nervous system [adenosine A(2A) receptor (ADORA2A) 1083C-->T] is associated with habitual caffeine consumption. DESIGN: Subjects (n = 2735) were participants from a study of gene-diet interactions and risk of myocardial infarction who did not have a history of hypertension. Genotype frequencies were examined among persons who were categorized according to their self-reported daily caffeine intake, as assessed with a validated food-frequency questionnaire. RESULTS: The ADORA2A, but not the CYP1A2, genotype was associated with different amounts of caffeine intake. Compared with persons consuming <100 mg caffeine/d, the odds ratios for having the ADORA2A TT genotype were 0.74 (95% CI: 0.53, 1.03), 0.63 (95% CI: 0.48, 0.83), and 0.57 (95% CI: 0.42, 0.77) for those consuming 100-200, >200-400, and >400 mg caffeine/d, respectively. The association was more pronounced among current smokers than among nonsmokers (P for interaction = 0.07). Persons with the ADORA2A TT genotype also were significantly more likely to consume less caffeine (ie, <100 mg/d) than were carriers of the C allele [P = 0.011 (nonsmokers), P = 0.008 (smokers)].
CONCLUSION: Our findings show that the probability of having the ADORA2A 1083TT genotype decreases as habitual caffeine consumption increases. This observation provides a biologic basis for caffeine consumption behavior and suggests that persons with this genotype may be less vulnerable to caffeine dependence.
Source : Am J Clin Nutr 2007 vol.86 (1), pp 240 - 244
Pharmacokinetic and pharmacodynamic interactions between zolpidem and caffeine
Cysneiros, R. M.; Farkas, D.; Harmatz, J. S.; von Moltke, L. L.; Greenblatt, D. J.
The kinetic and dynamic interaction of caffeine and zolpidem was evaluated in a double-blind, singledose, six-way crossover study of 7.5 mg zolpidem (Z) or placebo (P) combined with low-dose caffeine (250 mg), high-dose caffeine (500 mg), or placebo. Caffeine coadministration modestly increased maximum plasma concentration (C(max)) and area under the plasma concentration-time curve of zolpidem by 30-40%, whereas zolpidem did not significantly affect the pharmacokinetics of caffeine or its metabolites. Compared to P+P, Z+P significantly increased sedation, impaired digit-symbol substitution test performance, slowed tapping speed and reaction time, increased EEG relative beta amplitude, and impaired delayed recall. Caffeine partially, but not completely, reversed most pharmacodynamic effects of zolpidem. Thus, caffeine only incompletely reverses zolpidem's sedative and performance-impairing effects, and cannot be considered as an antidote to benzodiazepine agonists.
Source : Clin Pharmacol Ther 2007 vol.82 (1), pp 54 - 62
Caffeine analogs: biomedical impact
Daly, J. W.
Caffeine, widely consumed in beverages, and many xanthine analogs have had a major impact on
biomedical research. Caffeine and various analogs, the latter designed to enhance potency and selectivity toward specific biological targets, have played key roles in defining the nature and role of adenosine
receptors, phosphodiesterases, and calcium release channels in physiological processes. Such xanthines and other caffeine-inspired heterocycles now provide important research tools and potential therapeutic agents for intervention in Alzheimer's disease, asthma, cancer, diabetes, and Parkinson's disease. Such compounds also have activity as analgesics, antiinflammatories, antitussives, behavioral stimulants, diuretics/natriuretics, and lipolytics. Adverse effects can include anxiety, hypertension, certain drug interactions, and withdrawal symptoms.
Source : Cell Mol Life Sci 2007 vol.64 (16), pp 2153 - 2169
Influence of coffee drinking and cigarette smoking on the risk of primary late onset blepharospasm:
. Defazio, G.; Martino, D.; Abbruzzese, G.; Girlanda, P.; Tinazzi, M.; Fabbrini, G.; Colosimo, C.; Aniello, M. S.; Avanzino, L.; Buccafusca, M.; Majorana, G.; Trompetto, C.; Livrea, P.; Berardelli, A.
Prior coffee and smoking habits were investigated in a multicentre case control study involving 166 patients presenting with primary late onset blepharospasm (BSP), 228 hospital control patients with primary hemifacial spasm and 187 population control subjects from five Italian centres. Information on age at disease onset, smoking and coffee drinking status at the reference age and average number of cups of coffee drunk/cigarettes smoked per day reached high and similar test-retest reproducibility in case and control patients. Unadjusted logistic regression analysis yielded a significant inverse association of prior coffee drinking and cigarette smoking with case status for the control groups. After adjustment for age, sex, referral centre, disease duration, years of schooling and ever coffee drinking/cigarette smoking, as appropriate, the smoking estimate lacked significance whereas the association of coffee intake and BSP did not (cases vs hospital control PATIENTS: OR 0.37 (95% CI 0.20 to 0.67); cases vs population control SUBJECTS: OR 0.44 (95% CI 0.23 to 0.85)). The strength of the inverse association between BSP and coffee intake tended to increase with the average number of cups drunk per day. There was a significant correlation between age of BSP onset and number of cups per day (adjusted regression coefficient 1.73; p = 0.001) whereas no correlation was found with number of packs of cigarettes per day. Coffee drinking may be inversely associated with the development of primary BSP and this association may partly depend on the amount consumed.
Source : J Neurol Neurosurg Psychiatry 2007 vol.78 (8), pp 877 - 879
Glucose homeostasis remains altered by acute caffeine ingestion following 2 weeks of daily caffeine consumption in previously non-caffeine-consuming males
Dekker, M. J.; Gusba, J. E.; Robinson, L. E.; Graham, T. E.
Acute caffeine ingestion increases serum NEFA and plasma adrenaline and decreases insulin sensitivity. Although frequently suggested, it is not known if a tolerance to these alterations in glucose homeostasis is developed in habitual caffeine consumers. Our objective was to determine whether acute caffeine ingestion continued to alter insulin, glucose, NEFA and adrenaline during an oral glucose tolerance test (OGTT) following 14 d of caffeine consumption. Twelve caffeine-naive young males underwent four OGTTs over a 4-week period. Subjects ingested a gelatin-filled placebo (PLA) capsule on the first trial day and 5 mg caffeine/kg body weight on the remaining three trial days (day 0, day 7, day 14) before a 2 h OGTT. Following day 0 and day 7, subjects were given six dosages of 5 mg caffeine/kg to consume per d between trials. Serum insulin and blood glucose area under the curve (AUC) were significantly elevated (P < 0.05) v. PLA on day 0 (36 and 103 %, respectively) and were not different from PLA on day 7. On day 14, insulin AUC was 29 % greater than PLA (P < 0.05), and glucose was greater (P < 0.05) during the 22 first hour, although the 50 % elevation in glucose AUC was not different from PLA. Before the OGTT, caffeine resulted in greater (P < 0.05) serum NEFA and plasma adrenaline concentrations in all three caffeine trials, but both NEFA and adrenaline concentrations were decreased (P < 0.05) on day 14 v. day 0. Although 14 d of caffeine consumption by previously caffeine-naive subjects reduced its impact on glucose homeostasis, carbohydrate metabolism remained disrupted.
Source : Br J Nutr 2007 vol.98 (3), pp 556 - 562
The effects of caffeine on the preterm sheep ductus arteriosus
Clyman, R. I.; Roman, C.
Caffeine and other methyl xanthines are widely used in the neonatal period. A recent, randomized, placebo-controlled, multicenter trial found that infants who were randomly assigned to caffeine treatment had less need for pharmacologic and/or surgical closure of a patent ductus arteriosus (PDA). We hypothesized that the decreased need for pharmacologic and surgical closure of the PDA after caffeine treatment might be due to a direct effect of caffeine on ductus contractility. We examined preterm fetal lamb ductus arteriosus (from 24 fetuses, 105 +/- 4 d of gestation, term = 147 d), in vitro to determine the direct effects of caffeine on the isometric tension of the ductus arteriosus. Caffeine (0.003-0.3 mM) had no direct effect on ductus arteriosus tension, nor did it affect the contractile response of the ductus arteriosus to increasing oxygen concentrations. Caffeine's lack of effect was observed in both the presence and absence of indomethacin and NG-nitro-L-arginine methyl ester (L-NAME) (inhibitors of prostaglandin and nitric oxide production). In conclusion, we found no evidence of a direct effect of therapeutic caffeine concentrations on ductus contractility.
Source : Pediatr Res 2007 vol.62 (2), pp 167 - 169
Well-trained endurance athletes\' knowledge, insight, and experience of caffeine use
Desbrow, B.; Leveritt, M.
This descriptive cross-sectional study assessed the perceptions, knowledge, and experiences of caffeine use by athletes competing at the 2005 Ironman Triathlon World Championships. Questionnaires were distributed to 140 athletes (105 men and 35 women, 40.3 ±10.7 yr-old) representing 16 countries during prerace registration. A large proportion (73%) of these endurance athletes believe that caffeine is ergogenic to their endurance performance, and 84% believe it improves their concentration. The most commonly reported positive caffeine experiences related to in-competition use of cola drinks (65%) and caffeinated gels (24%). The athletes' ability to accurately quantify the caffeine content of common food items was limited. The most popular sources of caffeine information were self-experimentation (16%), fellow athletes (15%), magazines (13%) and journal articles (12%). 53% of the athletes could not identify an amount of caffeine required to improve their triathlon performance. Mean (± s.d.) suggested doses were 3.8 (± 3) mg/kg body wt. Few side effects associated with taking caffeine during exercise were reported.
Source : Intern J Sport Nutr Exerc Metab 2007 vol.17(4)
An examination of consumer exposure to caffeine from retail coffee outlets
Desbrow, B.; Hughes, R.; Leveritt, M.; Scheelings, P.
To analyse the distribution of caffeine doses obtainable from espresso coffee sold by a sample of commercial coffee vendors located on the Gold Coast, Qld, Australia. Design: A cross section of 'Espresso/short black' coffee samples were purchased and analysed for their caffeine content using micellar electrokinetic capillary chromatography (MEKC). Coffees were collected using systematic cluster sampling across five major retail centres. Results: Ninety-seven espresso samples were analysed. The mean (±SD) quantity of caffeine was 106±38mg/serve with a concentration of 2473±1092mg/l. There was considerable variation in caffeine content. The range per serve was 25-214mg whilst the concentration range was 580-7000mg/l. Twenty-four samples (24.7%) contained 120mg of caffeine or higher and 12 samples (12.3%) exceeded 167mg per serve.
Conclusions and implications: The number of heavily caffeinated samples differentiates these findings from frequently cited caffeine values and supports similar data recently collected throughout the United Kingdom. As a result, the accuracy of any previous intake modelling regarding caffeine use in the Australian population is in doubt. The present data suggests that the probability of consumer exposure to high caffeine doses is greater than previously anticipated. Greater sample numbers from a broader selection of venues is required to confirm the extent of caffeine content variance within retail ground coffees.
Source : Food Chem Toxicol 2007 vol.45(9), pp 1588 - 1592
Dietary fiber in brewed coffee
Diaz-Rubio, M. E.; Saura-Calixto, F.
Coffee beans are rich in nondigestible polysaccharides (dietary fiber), which may partially pass into brewed coffee; however, to the authors' knowledge, there is not enough literature on dietary fiber in brewed coffee. A specific method to determine dietary fiber in beverages (enzymatic treatment plus dialysis) was applied to the coffees brewed by the most common methods (espresso, filter, soluble); results showed that brewed coffee contained a significantly higher amount of soluble dietary fiber (0.47-0.75 g/100 mL of coffee) than other common beverages. Coffee dietary fiber contains a large amount of associated antioxidant phenolics (8.7-10.5 mg/100 mL of brewed coffee).
Source : J Agric Food Chem 2007 vol.55 (5), pp 1999 - 2003
Caffeine as an adjuvant to Ibuprofen in treating childhood headaches
Dooley, J. M.; Gordon, K. E.; Wood, E. P.; Brna, P. M.; MacSween, J.; Fraser, A.
In adults, caffeine has been shown to enhance the effectiveness of most analgesics, including ibuprofen. This double-blind cross-over pilot study evaluated the effect of ibuprofen and caffeine compared with ibuprofen and placebo in 12 children with headaches. Patients completed diaries for both headaches. Outcome measures included a five-faces severity scale, a measure of clinical disability, and a scale of pain severity. Comparison of the cumulative response scores revealed a trend toward a greater response to ibuprofen-caffeine treatment of headaches (P = 0.14, P = 0.09, and P = 0.07 for the three measures, respectively). Further larger studies are needed to confirm this effect and to identify potential responders.
Source : Pediatr Neurol 2007 vol.37 (1), pp 42 - 46
Clozapine-resistant psychosis, smoking, and caffeine: managing the neglected effects of substances that our patients consume every day
Dratcu, L.; Grandison, A.; McKay, G.; Bamidele, A.; Vasudevan, V.
More than 30% of patients with psychotic disorders who are refractory to antipsychotic treatment also fail to respond to clozapine. Despite the high prevalence of smoking and caffeine use in the psychiatric population, these habits are usually overlooked as factors contributing to antipsychotic treatment failure. We describe 2 male patients with severe treatment-resistant psychosis, one with schizophrenia and the other with bipolar affective disorder-both of whom smoked heavily, and the latter also consumed enormous amounts of caffeine-whose symptoms were refractory to clozapine. Both patients experienced a major, sustained amelioration of their psychotic symptoms when clozapine treatment was recommenced under supervision in the inpatient setting and the pharmacological interactions between clozapine, smoking, and caffeine were considered. Therapeutic strategies included gradual increases in daily doses of clozapine, monitoring clozapine plasma levels, using single daily doses of clozapine at night, and augmenting clozapine treatment with low doses of amisulpride, a selective antagonist at the dopamine D2 and D3 receptors. Smoking and excessive caffeine use are associated with poor therapeutic responses to clozapine and should be considered in the pharmacological management of treatment-refractory psychosis, regardless of the primary diagnosis.
Source : Am J Ther 2007 vol.14 (3), pp 314 - 318
Association of serum caffeine concentrations with serum glucose levels in caffeine-drug users and nonusers - results of German National Health Surveys
Du, Y.; Melchert, H. U.; Knopf, H.; Braemer-Hauth, M.; Pabel, E.
The purpose of this study was to explore the association of serum caffeine concentrations with serum glucose levels in caffeine-drug users and non-users, aiming at the chronic effects of caffeine on glucose metabolism in comparison with known acute effects of caffeine. Eight hundred and fourteen caffeine-drug users and 623 non-users were identified from German National Health Surveys. Their serum caffeine concentrations and glucose levels were measured. The associations of caffeine concentrations with glucose levels were established by correlation analysis and multivariable regression analysis in caffeine drug users and non-users separately. Antidiabetic therapy was considered. Caffeine concentrations were closely positively correlated to serum glucose levels in caffeine-drug users (Spearman r = 0.117, p = 0.001; partial r = 0.102, p = 0.020) particularly in women (Spearman r = 0.155, p < 0.001; partial r = 0.150, p = 0.005) although the correlation was weak as shown by multivariable regression analysis. The serum glucose levels were significantly higher (5.403 +/- 0.033 vs. 5.306 +/- 0.037 mmol/l) whereas the magnesium level was significantly lower (0.8941 +/- 0.0026 vs. 0.9024 +/- 0.0030 mmol/l) in caffeine-drug users than in non-users. No associations of caffeine concentrations with serum glucose levels were found in any groups of caffeine-drug non-users in our study. Whereas acute intake of caffeine-drugs may impair glucose metabolism, chronic intake of caffeine exclusively from diet has little effects on glucose metabolism and therefore may not contribute to the risk reduction of type 2 diabetes that was found in recent coffee consumption studies.
Source : Diabetes Obes Metab 2007 vol.9 (5), pp 756 - 758
Cardiotoxicity of ma huang/caffeine or ephedrine/caffeine in a rodent model system
Dunnick, J. K.; Kissling, G.; Gerken, D. K.; Vallant, M. A.; Nyska, A.
Ma Huang (equivalent to 0, 12.5, 25, or 50 mg/kg ephedrine) or ephedrine (0, 6.25, 12.5, 25 mg/kg) were administered as one bolus oral dose to male F344 rats with and without caffeine. The herbal medicine Ma Huang (ephedra) in combination with caffeine caused rapid clinical signs of toxicity including salivation, hyperactivity, ataxia, and eventually lethargy, and failure to respond to stimuli. When this syndrome of clinical signs emerged, animals were moribund sacrificed, and a histological analysis for heart lesions performed. Cardiotoxicity included hemorrhage, necrosis, and degeneration in the ventricles or interventricular septum within 2-4 hours after treatment with Ma Huang (ephedra)/caffeine or ephedrine (the principal active component in Ma Huang)/caffeine. There was a steep dose response curve for cardiotoxicity with minimal toxicity seen at levels of Ma Huang (equivalent to 12.5 mg/kg ephedrine) with caffeine. However, cardiotoxic lesions occurred in 28% of animals with Ma Huang dosages equivalent to 25 mg/kg ephedrine with 15 or 30 mg/kg caffeine, and in 90% of animals at Ma Huang exposures equivalent to 50 mg/kg ephedrine with 15 or 30 mg/kg caffeine. Cardiotoxic lesions occurred in 47% of animals in the 25 mg/kg ephedrine groups with caffeine at 7.25, 15, or 30 mg/kg. There was no statistical difference in the occurrence of cardiotoxic lesions when 15 or 30 mg/kg caffeine was combined with Ma Huang equivalent to 25 or 50 mg/kg ephedrine; likewise there was no statistical difference in the occurrence of cardiotoxic lesions when 7.25, 15, or 30 mg/kg caffeine was combined with 25 mg/kg ephedrine. These results show that the cardiotoxic effects of the herbal medicine, Ma Huang, are similar to that of ephedrine, the principal active ingredient in the herbal medicine. The combination of Ma Huang or ephedrine with caffeine enhanced the cardiotoxicity over that with the herbal medicine or the active ingredient alone.
Source : Toxicol Pathol 2007 vol.35 (5), pp 657 - 664
Tea and coffee as the main sources of oxalate in diets of patients with kidney oxalate stones
Gasinska, A.; Gajewska, D.
Dietary habits were studied for 12 men and 10 women (aged 23-75 yr) susceptible to kidney stones, with particular regard to significance of oxalate intake for kidney stone formation. Daily dietary oxalate intake was 354 ± 261 and 406 ± 265 mg for men and women, respectively, which was markedly higher than values found in previous research. Main sources of oxalate in the diet were regular tea and coffee (80-85% of intake); only 15-20% of dietary oxalate was derived from other plant foods. Patients tended not to adhere to recommendations for high fluid intake and avoidance of high-oxalate beverages, choosing to consume black tea in many cases. Daily intake of Ca was low and did not exceed 520 mg; vitamin C intake was higher than Polish Dietary Reference Intake (DRI) and vitamin B6 intake lower than DRI. Results are discussed with regard to role of diet in kidney stone management and prevention.
Source : Roczniki Panstwowego Zakladu Higieny.2007 vol.58(1), pp 61 - 67 (not available on line)
Effect of coffee melanoidin on human hepatoma HepG2 cells. Protection against oxidative stress induced by tert-butylhydroperoxide
Goya, L.; Delgado-Andrade, C.; Rufian-Henares, J. A.; Bravo, L.; Morales, F. J.
Melanoidins were isolated from brewed coffee and subjected to simulated gastrointestinal digestion. Effects of digested coffee melanoidins (DCM) against oxidative stress were subsequently determined in a human hepatoma HepG2 cell model. Pretreatment of HepG2 cells with DCM for 2 or 20 h (0.5-10 mug/ml) was able to protect against against oxidative stress induced by tert-butylhydroperoxide (t-BOOH) as demonstrated by complete prevention of t-BOOH induced increases in cell damage and glutathione reductase and partial inhibition of decreases in glutathione and increases in malondialdehyde and glutathione peroxidase. Generation of reactive oxygen species as a result of t-BOOH treatment was not influenced by DCM treatment. Findings show that concn. of coffee DCM within a physiological range are able to evoke an antioxidative response in cell models.
Source : Mol Nutr Food Res 2007 vol.51(5), pp 536 - 545
Caffeinated beverage intake and the risk of heart disease mortality in the elderly: a prospective analysis
Greenberg, J. A.; Dunbar, C. C.; Schnoll, R.; Kokolis, R.; Kokolis, S.; Kassotis, J.
Motivated by the possibility that caffeine could ameliorate the effect of postprandial hypotension on a high risk of coronary events and mortality in aging, it was hypothesized that caffeinated beverage consumption decreases the risk of cardiovascular disease (CVD) mortality in the elderly. The objective of this study was to use prospective cohort study data to determine whether the consumption of caffeinated beverages exhibits this protective effect. Cox regression analyses were conducted for 426 CVD deaths that occurred during an 8.8-yr follow-up in the prospective first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. The analysis involved 6594 participants aged 32-86 yrs with no history of CVD at baseline. Participants aged 65 yr with higher caffeinated beverage intake exhibited lower relative risk of CVD and heart disease mortality than did participants with lower caffeinated beverage intake. It was a dose-response protective effect: the relative risk (95% CI) for heart disease mortality was 1.00 (referent), 0.77 (0.54, 1.10), 0.68 (0.49, 0.94) and 0.47 (0.32, 0.69) for <0.5, 0.5-2, 2-4 and 4 servings/day, respectively (P for trend = 0.003). A similar protective effect was found for caffeine intake in mg/day. The protective effective was found only in participants who were not severely hypertensive. No significant protective effect was found in participants aged <65 yr or in cerebrovascular disease mortality for those aged <greater than or equal to>65 yr. Habitual intake of caffeinated beverages provided protection against the risk of heart disease mortality among elderly participants in this prospective epidemiologic analysis.
Source : Am J Clin Nutr 2007 vol.85(2), pp 392 - 398
Inhibitory effects of caffeine on hippocampal neurogenesis and function
Han, M. E.; Park, K. H.; Baek, S. Y.; Kim, B. S.; Kim, J. B.; Kim, H. J.; Oh, S. O.
Caffeine is one of the most extensively consumed psychostimulants in the world. However, compared to short-term effects of caffeine, the long-term effects of caffeine consumption on learning and memory are poorly characterized. The present study found that long-term consumption of low dose caffeine (0.3 g/L) slowed hippocampus-dependent learning and impaired long-term memory. Caffeine consumption for 4 weeks also significantly reduced hippocampal neurogenesis compared to controls. From these results, we concluded that long-term consumption of caffeine could inhibit hippocampus-dependent learning and memory partially through inhibition of hippocampal neurogenesis.
Source : Biochem Biophys Res Commun 2007 vol.356 (4), pp 976 - 980
Habitual coffee but not green tea consumption is inversely associated with metabolic syndrome: an epidemiological study in a general Japanese population
Hino, A.; Adachi, H.; Enomoto, M.; Furuki, K.; Shigetoh, Y.; Ohtsuka, M.; Kumagae, S.; Hirai, Y.; Jalaldin, A.; Satoh, A.; Imaizumi, T.
In Japan, metabolic syndrome used to be rare, and the level of coffee consumption was low. However, the Japanese life style has been changing rapidly, and these changes have been associated with a steady increase in the frequency of metabolic syndrome and with greater consumption of coffee. We examined the relationship between metabolic syndrome and the consumption of coffee or green tea. A total of 1902 Japanese aged over 40 years (785 men and 1117 women) received population-based health check-up in 1999. We measured components of metabolic syndrome (blood pressure, waist circumference, fasting plasma glucose, and lipid profiles). Eating and drinking patterns were evaluated by a food frequency questionnaire. Multivariate analyses were performed to clarify the association between coffee or green tea consumption and the components of metabolic syndrome. All components of metabolic syndrome except for HDL-cholesterol were significantly (p<0.01) and inversely related to coffee but not green tea consumption by multivariate analysis after adjusting for confounding factors. The larger was the number of components of metabolic syndrome, the lower was the level of coffee consumption (p<0.0001). In addition, there was a high frequency of metabolic syndrome in small coffee drinkers. Thus, coffee but not green tea consumption was inversely associated with metabolic syndrome.
Source : Diabetes Res Clin Pract 2007 vol.76 (3), pp 383 - 389
Effect of nutritionally enriched coffee consumption on aerobic and anaerobic exercise performance
Hoffman, J. R.; Kang, J.; Ratamess, N. A.; Jennings, P. F.; Mangine, G. T.; Faigenbaum, A. D.
The purpose of this study was to compare nutritionally enriched JavaFit coffee (JF) to commercially available decaffeinated coffee (P) with regard to impact on endurance and anaerobic power performance in a physically active, college-aged population. Ten subjects (8 men, 2 women) performed two 30-second Wingate anaerobic power tests and 2 cycle ergometer tests (75% VO2 max) to exhaustion. Mean VO2 was measured during each endurance exercise protocol. Excess postexercise oxygen consumption (EPOC) and respiratory exchange ratio (RER) were recorded for 30 minutes following all exercise sessions. Area under the curve analysis was used to compare EPOC between JF and P for all exercise sessions. No differences were seen between JF and P in any of the power performance measures. However, time to exhaustion was significantly (p = 0.05) higher in JF (35.3 +/- 15.2 minutes) compared with P (27.3 +/- 10.7 minutes). No difference between JF and P were seen in EPOC in either the aerobic or anaerobic exercise sessions. A significant (p < 0.05) difference in average 30-minute postanaerobic power exercise RER was seen between JF (0.87 +/- 0.04) and P (0.83 +/- 0.03), but not following endurance exercise. A nutritionally-enriched coffee beverage appears to enhance time to exhaustion during aerobic exercise, but does not provide an ergogenic benefit during anaerobic exercise.
Source : J Strength Cond.Res 2007 ol.21 (2), pp 456 - 459
Coffee consumption and the incidence of antihypertensive drug treatment in Finnish men and women
Hu, G.; Jousilahti, P.; Nissinen, A.; Bidel, S.; Antikainen, R.; Tuomilehto, J.
Only 2 prospective studies have previously investigated the association between coffee consumption and incident hypertension, and the findings are equivocal. OBJECTIVE: The objective was to determine the relation between coffee consumption and the incidence of antihypertensive drug treatment. DESIGN: We prospectively followed 24 710 Finnish subjects aged 25-64 y without a history of antihypertensive drug treatment, coronary heart disease, or stroke at baseline. Daily coffee consumption was assessed by questionnaires. RESULTS: During a mean follow-up period of 13.2 y, 2505 participants started antihypertensive drug treatment. The multivariate-adjusted (age, sex, study year, education, leisure-time physical activity, smoking, body mass index, high total cholesterol, history of diabetes, and alcohol, tea, fruit, vegetable, sausage, and bread consumption) hazard ratios for antihypertensive drug treatment associated with the amount of coffee consumed daily (0-1, 2-3, 4-5, 6-7, or >/=8 cups) were 1.00, 1.29 (95% CI: 1.09, 1.54), 1.26 (95% CI: 1.06, 1.49), 1.24 (95% CI: 1.04, 1.48), and 1.14 (95% CI: 0.94, 1.37) (P for trend = 0.024), respectively. This trend became marginally significant after additional adjustment for baseline systolic blood pressure (P for trend = 0.077).
CONCLUSIONS: The results indicate that coffee drinking seems to increase the risk of antihypertensive drug treatment, and this risk was higher in subjects with low-to-moderate coffee intakes; however, there was no significantly increased trend in drinkers of approximately 1 cup (100 mL)/d or >/=8 cups/d.
Source : Am J Clin Nutr 2007 vol.86 (2), pp 457 - 464
Evaluation of cardiovascular effects of caffeine using telemetric monitoring in the conscious rat
Ilback, N. G.; Siller, M.; Stalhandske, T.
Caffeine is commonly consumed by the general population in tea, coffee and certain stimulatory drinks. It has a number of physiological effects, including increased alertness and increased cardiovascular activity. This study used telemetry to study the effects on physical activity, body temperature and the cardiovascular system induced by caffeine intake in rats. The results indicated that caffeine increased spontaneous physical activity, heart rate and systolic-diastolic blood pressure in a dose-dependent manner. The dose required for long-lasting signs of intoxication in the rat was 45 mg/kg body weight.
Source : Food Chem Toxicol 2007 vol.45 (5), pp 834-842
Caffeine-induced Ca2+ release increases AMPK-dependent glucose uptake in rodent soleus muscle
Jensen, T. E.; Rose, A. J.; Hellsten, Y.; Wojtaszewski, J. F.; Richter, E. A.
Previous studies have proposed that caffeine-induced activation of glucose transport in skeletal muscle is independent of AMP-activated protein kinase (AMPK) because alpha-AMPK Thr172 phosphorylation was not increased by caffeine. However, our previous studies, as well as the present, show that AMPK phosphorylation measured in whole muscle lysate is not a good indicator of AMPK activation in rodent skeletal muscle. In lysates from incubated rat soleus muscle, a predominant model in previous caffeinestudies, both acetyl-CoA carboxylase-beta (ACCbeta) Ser221 and immunoprecipitated alpha(1)-AMPK activity increased with caffeine incubation, without changes in AMPK phosphorylation or immunoprecipitated alpha(2)-AMPK activity. This pattern was also observed in mouse soleus muscle, where only ACCbeta and alpha(1)-AMPK phosphorylation were increased following caffeine treatment. Preincubation with the selective CaMKK inhibitor STO-609 (5 muM), the CaM-competitive inhibitor KN-93 (10 muM), or the SR Ca(2+) release blocking agent dantrolene (10 muM) all inhibited ACCbeta phosphorylation and alpha(1)-AMPK phosphorylation, suggesting that SR Ca(2+) release may work through a CaMKK-AMPK pathway. Caffeine-stimulated 2-deoxyglucose (2DG) uptake reflected the AMPK activation pattern, being increased with caffeine and inhibited by STO-609, KN-93, or dantrolene. The inhibition of 2DG uptake is likely causally linked to AMPK activation, since muscle-specific expression of a kinase-dead AMPK construct greatly reduced caffeine-stimulated 2DG uptake in mouse soleus. We conclude that a SR Ca(2+)-activated CaMKK may control alpha(1)-AMPK activation and be necessary for caffeine-stimulated glucose uptake in mouse soleus muscle.
Source : Am J Physiol Endocrinol Metab 2007 vol.293 (1), pp E286 - E292
The effect of cigarette smoking, tea, and coffee consumption on the progression of Parkinson\'s disease
Kandinov, B.; Giladi, N.; Korczyn, A. D.
Previous epidemiological studies found a negative association between cigarette smoking, tea or coffee drinking with the occurrence of Parkinson's disease (PD). However, it is unknown how these factors affect the rate of progression of the disease. A retrospective study was conducted among 278 consecutive PD patients. Data on smoking and coffee or tea consumption were obtained through direct or proxy interviews, and the time from onset of motor symptoms until reaching Hoehn & Yahr (H&Y) stage 3 was retrieved from the case records. Cox proportional hazards model and Kaplan-Meyer model were used to estimate whether the dependent variables (smoking, drinking coffee or tea) affect the rate of progression of the disease, which was measured by the time it took patients to reach H&Y stage 3. We found that disease progression was not affected by cigarette smoking, tea or coffee consumption. The present study suggests that these variables do not have a disease modifying effect in already diagnosed PD patients.
Source : Parkinsonism Relat Disord 2007 vol.13 (4), pp 243 - 245
Effects of caffeine on the freezing of gait in Parkinson\'s disease
Kitagawa, M.; Houzen, H.; Tashiro, K.
Caffeine is a nonselective competitive blockade of adenosine A1 and A2A receptors. In this report, we studied the efficacy of 100 mg of caffeine per day on the freezing of gait (FOG) for patients with Parkinson's disease. Different subtypes of FOG showed different therapeutic responses to caffeine. Caffeine improved "total akinesia" type of FOG, but had no effect on "trembling in place." Tolerance developed to the beneficial effect of caffeine on FOG within a few months, but a 2-week caffeine withdrawal period could restore the effect of caffeine.
Source : Mov Disord 2007 vol.22 (5), pp 710 - 712
Effect of carbonated beverages, coffee, sports and high energy drinks, and bottled water on the in vitro erosion characteristics of dental enamel
Kitchens, M.; Owens, B. M.
This study evaluated the effect of carbonated and non-carbonated beverages, bottled and tap water, on the erosive potential of dental enamel with and without fluoride varnish protection. MATERIALS AND METHODS: Beverages used in this study included: Coca Cola Classic, Diet Coke, Gatorade sports drink, Red Bull high-energy drink, Starbucks Frappuccino coffee drink, Dasani water (bottled), and tap water (control). Enamel surfaces were coated with Cavity Shield 5% sodium fluoride treatment varnish. Twenty-eight previously extracted human posterior teeth free of hypocalcification and caries were used in this study. The coronal portion of each tooth was removed and then sectioned transverse from the buccal to lingual surface using a diamond coated saw blade. The crown sections were embedded in acrylic resin blocks leaving the enamel surfaces exposed. The enamel surfaces were polished using 600 to 2000 grit abrasive paper and diamond paste. Test specimens were randomly distributed to seven beverage groups and comprised 4 specimens per group. Two specimens per beverage group were treated with a fluoride varnish while 2 specimens did not receive fluoride coating. Surface roughness (profilometer) readings were performed at baseline (prior to fluoride treatment and immersion in the beverage) and again, following immersion for 14 days (24 hours/day). The test beverages were changed daily and the enamel specimens were immersed at 37 degrees C. Surface roughness data was evaluated using multiple factor ANOVA at a significance level of p<0.05. RESULTS: Results showed that Coca-Cola Classic, Gatorade and Red Bull with/without fluoride revealed the highest post-treatment surface roughness measurements. Coca-Cola Classic, Diet Coke, Gatorade, and Red Bull all showed significantly higher post treatment readings than StarBucks coffee, Dasani water, and tap water. Fluoride varnish was not a significant impact factor; however, beverage (type) and exposure time were significant impact variables.
CONCLUSION: Both carbonated and non-carbonated beverages displayed a significant erosive effect on dental enamel; however, fluoride varnish treatments did not demonstrate a significant protective influence on enamel surfaces.
Source : J Clin Pediatr Dent 2007 vol.31 (3), pp 153 - 159 (not available on line)
Effect of cytochrome P450 (CYP) inducers on caffeine metabolism in the rat
Kot, M.; Daniel, W. A.
Our previous studies, carried out using rat cDNA-expressed cytochrome P450 (CYP) isoforms, liver microsomes and specific CYP inhibitors, showed that the 1-N- and 3-N-demethylation of caffeine at a therapeutic concentration was predominantly catalyzed by CYP1A2 and CYP2C, its 7-N-demethylation was governed by P450s of the CYP2C subfamily, while its 8-hydroxylation was specifically mediated by CYP1A2. The present study was aimed at corroborating the above-described results using another experimental model, i.e. a study of caffeine metabolism in the liver microsomes and specific CYP inducers. Animals received one of the following inducers: beta-naphthoflavone (100 mg/kg ip for 4 days), phenobarbital (10 mg/kg for 6 days or 100 mg/kg ip for 4 days), pregnenolone 16alpha-carbonitrile (100 mg/kg ip for 4 days) or 15% ethanol ( approximately 11 g/kg in drinking water for 6 days). Sixteen hours after the last dose of an inducer liver microsomes were prepared and the caffeine metabolism and CYP isoform activities (testosterone 2alpha-, 2beta-, 6beta-, 7alpha-, 16beta-hydroxylation and warfarin 7-hydroxylation) were investigated. beta-Naphthoflavone (mainly a CYP1A inducer and CYP2C11 inhibitor) potently accelerated the metabolism of caffeine, the effect on 7-N-demethylation being the weakest. Moreover, the influence of beta-naphthoflavone on caffeine metabolism was more potent at the substrate concentration of 100 muM than 800 muM, in particular in the case of 7-N-demethylation and 8-hydroxylation. Pregnenolone-16alpha-carbonitrile (mainly a CYP3A inducer and CYP2C11 inhibitor) moderately induced 8-hydroxylation only. Phenobarbital (an inducer of CYP2B and other CYPs and a CYP2C11 inhibitor) moderately stimulated the metabolism of caffeine, but practically did not affect 7-Ndemethylation. Ethanol (mainly a CYP2E1 inducer) modestly increased the rates of the N-demethylation reactions. The presently obtained data confirm the pivotal role of CYP1A2 in the metabolism of caffeine, as well as the involvement of CYP3A in the 8-hydroxylation of caffeine and that of CYP2C11 in its 7-Ndemethylation.
Source : Pharmacol Rep 2007 vol.59 (3), pp 296 - 305
Involvement of adenosinergic receptors in anxiety related behaviours
Kulkarni, S. K.; Singh, K.; Bishnoi, M.
In the present study, the effect of adenosine (A1 and A2 receptor agonist), caffeine (A2A receptor antagonist), theophylline (A2A receptor antagonist) and their combination was studied in anxiety related behaviours using elevated zero maze and elevated plus maze paradigms and compared their various behavioural profiles. Adenosine (10, 25, 50,100 mg/kg) significantly showed anxiolytic effect at all the doses, whereas caffeine (8, 15, 30, 60 mg/kg) and theophylline (30, 60 mg/kg) showed psychostimulatory action at lower doses and anxiogenic effect at higher doses. Pretreatment with caffeine (8, 15, 30 mg/kg) and theophylline (30 mg/kg) reversed the anxiolytic effect of adenosine. The study suggested the involvement of adenosinergic receptor system in anxiety related behaviours.
Source : Indian J Exp Biol 2007 vol.45 (5), pp 439 - 443
Interactions between 3,4-methylenedioxymethamphetamine, methamphetamine, ketamine, and caffeine in human intestinal Caco-2 cells and in oral administration to rats
Kuwayama, K.; Inoue, H.; Kanamori, T.; Tsujikawa, K.; Miyaguchi, H.; Iwata, Y.; Miyauchi, S.; Kamo, N.; Kishi, T.
Amphetamine-type stimulants (ATSs) are often abused orally in the form of tablets for recreational purposes. The ATS tablets contain one or more active ingredients such as 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine (MA), ketamine (KA), and caffeine (CF). The aim of this work is to determine whether such components in tablets interact with each other in intestinal absorption. The interactions between MDMA, MA, KA, and CF in the uptake and permeation by human intestinal epithelial Caco-2 cell line were investigated in monolayer cultures. MDMA, MA, and KA mutually inhibited the uptakes by Caco-2 cells. The inhibition of MA uptake by KA was the greatest of all combinations (72.6% inhibition). Similarly, MDMA, MA, and KA mutually inhibited the permeation from the apical to the basolateral side through Caco-2 cells. Although CF did not affect the uptakes of MDMA, MA, and KA, CF enhanced the permeation of MDMA in comparison to MDMA alone. In addition, the interaction of MA with KA and that of MDMA with CF in intestinal absorption were investigated by oral administration to rats. The area under the plasma concentration-time curve of MA significantly decreased by co-administration with KA in comparison to MA alone, while that of MDMA significantly increased by co-administration with CF in comparison to MDMA alone. The results in rats were similar to those in Caco-2 cells. These findings suggest that the intestinal absorption of similar compounds with amine moieties such as MDMA, MA, and KA are mediated by a common transport system, and that CF affects the absorption of MDMA in a different way from the transport system. In human, intakes of ATS tablets mixed with such components might result in similar interactions in intestinal absorption to those in Caco-2 cells and rats.
Source : Forensic Sci Int vol.170 Issue 2-3 pp 183 - 188
Exaggeration of postprandial hyperglycemia in patients with type 2 diabetes by administration of caffeine in coffee
Lane, J. D.; Hwang, A. L.; Feinglos, M. N.; Surwit, R. S.
To test whether caffeine administered in coffee increases postprandial hyperglycemia in patients with type 2 diabetes who are habitual coffee drinkers. METHODS: The study used a withinsubject, double-blind, placebo-controlled experimental design. Twenty adult coffee drinkers (11 Women and 9 men) with type 2 diabetes treated with diet, exercise, orally administered antidiabetic agents, or some combination of these factors completed two mixed-meal tolerance tests (MMTT) after an overnight fast. Before the MMTT, each study participant received 250 mg of caffeine in 16 oz (475 mL) of decaffeinated coffee or decaffeinated coffee alone, with the treatment order counterbalanced in the group. Fasting and 1-hour and 2-hour postprandial blood samples were collected for measurement of plasma glucose and insulin concentrations. RESULTS: Glucose and insulin responses to the MMTT were quantified by the incremental areas under the 2-hour concentration-time curves (AUC2h). Administration of caffeine in decaffeinated coffee increased postprandial glucose and insulin responses (both P = 0.02). The mean plasma glucose AUC2h was 28% larger and the mean plasma insulin AUC2h was 19% larger after administration of caffeine than after administration of placebo.
CONCLUSION: Other constituents in coffee did not prevent the exaggeration of postprandial hyperglycemia by caffeine in these patients with type 2 diabetes, who were habitual coffee drinkers. Repeated on a daily basis, such effects could impair long-term glucose control in those patients with type 2 diabetes who habitually drink coffee or other caffeinated beverages.
Source : Endocr Pract 2007 vol.13 (3), pp 239 - 243
Coffee consumption and risk of colorectal cancer in a population-based prospective cohort of Japanese men and women
Lee, K. J.; Inoue, M.; Otani, T.; Iwasaki, M.; Sasazuki, S.; Tsugane, S.
We prospectively examined the association between coffee consumption and the risk of developing colorectal cancer in a large population-based cohort study (the JPHC Study) of Japanese men and women. Data were analyzed from a population-based cohort of 96,162 subjects (46,023 men and 50,139 women). A total of 1,163 incident colorectal cancers were identified during the follow-up period, including 763 cases of colon cancer and 400 of rectal cancer. We observed a significant inverse association between coffee consumption and the risk of developing invasive colon cancer among women. Compared with those who almost never consumed coffee, women who regularly consumed 3 or more cups of coffee per day had a RR of 0.44 (95% CI = 0.19-1.04; p for trend = 0.04) after adjustment for potential confounding factors. However, no significant association was found for rectal cancer in women. In men, no significant decrease was observed in any colorectal cancer site. Further, additional analyses on the association of green tea consumption with colorectal cancer risk found no significant association in men or women. These findings suggest that coffee consumption may lower the risk of colon cancer among Japanese women.
Source : Int J Cancer 2007 vol.121 (6), pp 1312 - 1318
Voluntary exercise together with oral caffeine markedly stimulates UVB light-induced apoptosis and decreases tissue fat in SKH-1 mice
Lu, Y. P.; Nolan, B.; Lou, Y. R.; Peng, Q. Y.; Wagner, G. C.; Conney, A. H.
Treatment of SKH-1 mice orally with caffeine (0.1 mg/ml in the drinking water), voluntary running wheel exercise, or a combination of caffeine and exercise for 2 weeks (i) decreased the weight of the parametrial fat pads by 35, 62, and 77%, respectively; (ii) decreased the thickness of the dermal fat layer by 38, 42, and 68%, respectively; (iii) stimulated the formation of UVB-induced apoptotic sunburn cells in the epidermis by 96, 120, and 376%, respectively; and (iv) stimulated the formation of UVB-induced caspase 3 (active form)-positive cells in the epidermis by 92, 120, and 389%, respectively (average of two experiments). Oral administration of caffeine (0.4 mg/ml in the drinking water) in combination with voluntary exercise was less effective than administration of the low dose of caffeine in combination with exercise in stimulating UVB-induced apoptosis. Although orally administrated caffeine (0.1 mg/ml in the drinking water) or voluntary exercise for 2 weeks caused only a small nonsignificant stimulation of UVBinduced increase in the percentage of phospho-p53 (Ser-15)-positive cells in the epidermis (27 or 18%, respectively), the combination of the two treatments enhanced the UVB-induced increase in phospho-p53 (Ser-15)-positive cells by 99%. The plasma concentration of caffeine in mice ingesting caffeine (0.1-0.4 mg/ml drinking water) is similar to that in the plasma of most coffee drinkers (one to four cups per day). Our studies indicate a greater than additive stimulatory effect of combined voluntary exercise and oral administration of a low dose of caffeine on UVB-induced apoptosis.
Source : Proc Natl Acad Sci U S A v2007 vol.104 (31), pp 12936 - 12941
Does caffeine reverse the EAC cell-induced immune suppression?
Mandal, A.; Poddar, M. K.
The aim of this study was to investigate the effect of long-term consumption of caffeine in the development of Ehrlich ascites carcinoma (EAC) cells in adult female mice, 25-30 g, in relation to immune response. Mice were treated with caffeine (20 mgkg(-1) daily, p.o.) for 22-27 consecutive days or inoculated with EAC cells (5 x 10(6) cells/mL, i.p.), or both. Control mice, corresponding to experimental groups, were treated with corresponding vehicles under similar conditions. The lymphocyte viability, mitogen-induced proliferating activity, cytotoxicity and DNA fragmentation from blood, spleen and thymus of both control and experimental groups were measured as immune response parameters. An immune response index, corticosterone, was also measured in adrenals and plasma under similar conditions. Results showed that development of EAC cells caused immune suppression with a reduction of lymphocyte viability, cytotoxicity and proliferative activity and induction of DNA fragmentation in those tissues, as well as an increase in plasma corticosterone. Though long-term caffeine treatment (which resulted in tolerance to caffeine) alone did not alter significantly any of the immune response parameters studied, including corticosterone status (immune biomarker), the continuation of caffeine treatment during the development of EAC cells either restored or reduced the EAC cell-induced alteration in these parameters, including the HPA axis biomarker. These results suggest that long-term caffeine intake may inhibit or reverse the EAC cell-induced immune suppression.
Source : J Pharm Pharmacol 2007 vol.59 (7), pp 1001 - 1009
Dual regulation of the ATP-sensitive potassium channel by caffeine
Mao, X.; Chai, Y.; Lin, Y. F.
ATP-sensitive potassium (K(ATP)) channels couple cellular metabolic status to changes in membrane electrical properties. Caffeine (1,2,7-trimethylxanthine) has been shown to inhibit several ion channels; however, how caffeine regulates K(ATP) channels was not well understood. By performing single-channel recordings in the cell-attached configuration, we found that bath application of caffeine significantly enhanced the currents of Kir6.2/SUR1 channels, a neuronal/pancreatic K(ATP) channel isoform, expressed in transfected human embryonic kidney (HEK)293 cells in a concentration-dependent manner. Application of nonselective and selective phosphodiesterase (PDE) inhibitors led to significant enhancement of Kir6.2/SUR1 channel currents. Moreover, the stimulatory action of caffeine was significantly attenuated by KT5823, a specific PKG inhibitor, and, to a weaker extent, by BAPTA/AM, a membrane-permeable Ca(2+) chelator, but not by H-89, a selective PKA inhibitor. Furthermore, the stimulatory effect was completely abrogated when KT5823 and BAPTA/AM were co-applied with caffeine. In contrast, the activity of Kir6.2/SUR1 channels was decreased rather than increased by caffeine in cellfree inside-out patches, while tetrameric Kir6.2LRKR368/369/370/371AAAA channels were suppressed regardless of patch configurations. Caffeine also enhanced the single-channel currents of recombinant Kir6.2/SUR2B channels, a nonvascular smooth muscle K(ATP) channel isoform, although the increase was smaller. Moreover, bidirectional effects of caffeine were reproduced on the K(ATP) channel present in the Cambridge rat insulinoma G1 (CRI-G1) cell line. Taken together, our data suggest that caffeine exerts dual regulation on the function of K(ATP) channels: an inhibitory regulation that acts directly on Kir6.2 or some closely associated regulatory protein(s), and a sulfonylurea receptor (SUR)-dependent stimulatory regulation that requires cGMP-PKG and intracellular Ca(2+)-dependent signaling.
Source : Am J Physiol Cell Physiol 2007 vol.292 (6), pp C2239 - C2258
Neonatal withdrawal syndrome after chronic maternal drinking of mate
Martin, I.; Lopez-Vilchez, M. A.; Mur, A.; Garcia-Algar, O.; Rossi, S.; Marchei, E.; Pichini, S.
The premature newborn of a mother who reported drinking mate during pregnancy presented with increased jitteriness and irritability, high-pitched cry, hypertonia in the limbs, and brisk tendon reflexes consistent with neonatal withdrawal syndrome. High concentrations of caffeine and theobromine were detected in various maternal and neonatal biological matrices (placenta, cord serum, neonatal urine, maternal and neonatal hair, meconium, and breast milk), demonstrating both acute and chronic prenatal and postnatal exposure to these methylxanthines, contained in high amounts in homemade mate. Symptoms progressively disappeared at 84 hours of age, although intermittent irritability was still present when the infant was discharged at 24 days of age. Fluctuating caffeine (and theobromine) content in different breast milk feeds likely generated the baby's irritability, due to either the physiological stimulatory effects of the methylxanthines or postnatal withdrawal syndrome as the substances cleared from the body. The mother was strongly advised to initiate a considerable, progressive, constant reduction of mate consumption to a maximum of 2 cups a day for the duration of breastfeeding.
Source : Ther Drug Monit 2007 vol.29 (1), pp 127 - 129
Evidence behind the WHO guidelines: hospital care for children: is caffeine useful in the prevention of apnoea of prematurity?
McCallum, A. D.; Duke, T.
No abstract available
Source : J Trop Pediatr 2007 vol.53 (2), pp 76 - 77
Caffeine inhibits adenosine-induced accumulation of hypoxia-inducible factor-1alpha, vascular endothelial growth factor, and interleukin-8 expression in hypoxic human colon cancer cells
Merighi, S.; Benini, A.; Mirandola, P.; Gessi, S.; Varani, K.; Simioni, C.; Leung, E.; Maclennan, S.; Baraldi, P. G.; Borea, P. A.
Frequent coffee consumption has been associated with a reduced risk of colorectal cancer in a number of case-control studies. Coffee is a leading source of methylxanthines, such as caffeine. The induction of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) is an essential feature of tumor angiogenesis, and the hypoxia-inducible factor-1 (HIF-1) transcription factor is known to be a key regulator of this process. In this study, we investigated the effects of caffeine on HIF-1 protein accumulation and on VEGF and IL-8 expression in the human colon cancer cell line HT29 under hypoxic conditions. Our results show that caffeine significantly inhibits adenosine-induced HIF-1alpha protein accumulation in cancer cells. We show that HIF-1alpha and VEGF are increased through A3 adenosine receptor stimulation, whereas the effects on IL-8 are mediated via the A2B subtype. Pretreatment of cells with caffeine significantly reduces adenosine-induced VEGF promoter activity and VEGF and IL-8 expression. The mechanism of caffeine seems to involve the inhibition of the extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and Akt, leading to a marked decrease in adenosine-induced HIF-1alpha accumulation, VEGF transcriptional activation, and VEGF and IL-8 protein accumulation. From a functional perspective, we observe that caffeine also significantly inhibits the A3 receptor-stimulated cell migration of colon cancer cells. Conditioned media prepared from colon cells treated with an adenosine analog increased human umbilical vein endothelial cell migration. These data provide evidence that adenosine could modulate the migration of colon cancer cells by an HIF-1alpha/VEGF/IL-8-dependent mechanism and that caffeine has the potential to inhibit colon cancer cell growth.
Source : Mol Pharmacol 2007 vol.72 (2), pp 395 - 406
Effects of caffeine on in vivo and in vitro oocyte maturation in mice
Miao, Y. L.; Shi, L. H.; Lei, Z. L.; Huang, J. C.; Yang, J. W.; Ouyang, Y. C.; Sun, Q. Y.; Chen, D. Y.
The objective was to investigate, using a mouse model, the effects of caffeine on the number of ovulated oocytes, the rate of oocyte maturation, the susceptibility of oocytes to activating stimuli, spindle morphology, and distribution of cortical granules (CGs). Mice were given caffeine (150mg/kg body weight ip) at various times relative to hCG (-2, 0, and +2h); in an in vitro study, 1, 5 or 10mM caffeine was added to the maturation culture. Caffeine had no effect on the quality of oocytes in vivo maturation, but caffeine was detrimental to the quality of oocytes matured in vitro. Further studies are needed to determine caffeine concentration in follicles relative to that in culture medium.
Source : Theriogenology 2007 vol.68 (4), pp 640 - 645 (not available on line)
Early menopause, association with tobacco smoking, coffee consumption and other lifestyle factors: a cross-sectional study
Mikkelsen, T. F.; Graff-Iversen, S.; Sundby, J.; Bjertness, E.
Early onset of menopause is a risk factor for several health problems. The objective was primarily to investigate the association between early menopause and current, past active and passive smoking. A second aim was to investigate the association between coffee and alcohol consumption and early menopause. METHODS: The present population-based cross-sectional study included a subsample of 2123 postmenopausal women born in 1940-41 who participated in the Oslo Health Study. Early menopause was defined as menopause occurring at an age of less than 45 years. We applied logistic regression analyses (crude and adjusted odds ratio (OR)) to examine the association between early menopause and selected lifestyle factors. RESULTS: Current smoking was significantly associated with early menopause (adj. OR, 1.59; 95% CI, 1.11-2.28). Stopping smoking more than 10 years before menopause considerably reduced the risk of early menopause (adj. OR, 0.13; 95% CI, 0.05-0.33). Total exposure to smoking (the product of number of cigarettes per day and time as a smoker) was positively related to early menopause and, at the highest doses, nearly doubled the odds (adj. OR, 1.93; 95% CI, 1.12-3.30). These data suggest a possible dose-response relationship between total exposure to smoking and early menopause, but no dose-response relationship was detected for the other variables examined. We found no significant association of coffee or alcohol consumption with early menopause. Of the lifestyle factors tested, high educational level (adj. OR, 0.50; 95% CI, 0.34-0.72) and high social participation (adj. OR, 0.60, 95% CI, 0.39-0.98) were negatively associated with early menopause.
CONCLUSION: This cross-sectional study shows an association between current smoking and early menopause. The data also suggest that the earlier a woman stops smoking the more protected she is from early menopause. Early menopause was not significantly associated with passive smoking, or alcohol or coffee consumption.
Source : BMC Public Health 2007 vol.7, pp 149
Caffeine and muscle cramps: a stimulating connection
Molema, M. M.; Dekker, M. C.; Voermans, N. C.; van Engelen, B. G.; Aarnoutse, R. E.
No abstract available
Source : Am J Med 2007 vol.120 (8), pp e1 - e2
The interoceptive Pavlovian stimulus effects of caffeine
Murray, J. E.; Li, C.; Palmatier, M. I.; Bevins, R. A.
The present research sought to test whether caffeine functioned as a Pavlovian cue in two ways--as a positive drug feature or as a conditional stimulus (CS). As a positive feature (Experiment 1), brief light presentations were followed by sucrose only on sessions in which caffeine (10 mg/kg) was administered. On intermixed saline sessions, light presentations were not followed by sucrose. The light came to control robust goal tracking (i.e., conditioned responding) only in caffeine sessions. Thus, caffeine disambiguates when the light was paired with sucrose. Decreasing the dose of caffeine decreased the conditioned responding evoked by the light (ED(50)=4.16 mg/kg). Neither nicotine nor amphetamine substituted for the caffeine feature. As a CS, caffeine (10 or 30 mg/kg, Experiments 2a and 2b, respectively) signalled intermittent access to sucrose--no light presentations. No sucrose or lights were presented on intermixed saline sessions. The caffeine CS, regardless of training dose, acquired the ability to evoke only a weak goal-tracking CR. The nature of this dissociation between caffeine as a drug feature and a CS is discussed within the context of past research finding a similar dissociation with amphetamine and chlordiazepoxide, but not with nicotine.
Source : Pharmacol Biochem Behav 2007 vol.86 (4), pp 838 - 846
Coffee and Maillard products activate NF-kappaB in macrophages via H2O2 production
Muscat, S.; Pelka, J.; Hegele, J.; Weigle, B.; Muench, G.; Pischetsrieder, M.
Immunomodulation effects of raw coffee extracts, roasted coffee and Maillard reaction products (MRP) were determined by studying effects on macrophages. Stimulation of macrophages with coffee induced activation and resulted in a 13x increase in nuclear translocation of transcription factor NFkappaB. Extracts of raw coffee were not active, indicating effects were related to MRP formed during roasting. In addition, MRP mixtures of ribose and lysine exerted 18 and 6x increased activation in PBS and cell culture medium, respectively. NF-kappaB activation was similar in transfected and untransfected human embryonic kidney cells, indicating that MRP exert activity independently of RAGE (receptor for advanced glycation end products). NF-kappaB activation by MRP was almost completely inhibited by coincubation with catalase, suggesting that H2O2 plays a key role in the process. No significant increase in IL-6 or NO production was noted due to MRP stimulation.
Source : Mol Nutri Food Res 2007 vol.51(5), pp 525 - 535
Caffeine and 35% carbon dioxide challenge tests in panic disorder
Nardi, A. E.; Valenca, A. M.; Lopes, F. L.; Melo-Neto, V. L.; Freire, R. C.; Veras, A. B.; Nascimento, I.; King, A. L.; Soares-Filho, G. L.; Mezzasalma, M. A.; Zin, W. A.
Our aim was to compare the demographic and clinical features of panic disorder (PD) patients with agoraphobia-DSM-IV-who had a panic attack after both an oral caffeine and the 35% carbon dioxide (CO2) challenge tests (responsive group) and compare them with PD patients who did not have a panic attack after both tests (non-responsive group). We examined 83 PD patients submitted to a 35% CO2 test and to an oral caffeine (480 mg) intake within 1 week interval. A panic attack was induced in 51 (61.4%) patients during the CO2 test (chi2=31.67, df=1, p<0.001) and in 38 (45.8%) patients during the caffeine test (chi2=18.28, df=1, p=0.023). All patients who had a panic attack during the caffeine test also had a panic attack during the CO2 test (n=38)-responsive group. The responsive had more (chi2=24.55, df=1, p=0.008) respiratory PD subtype, disorder started earlier (Mann-Whitney, p<0.001) had a higher familial prevalence of PD (chi2=20.34, df=1, p=0.019), less previous alcohol abuse (chi2=23.42, df=1, p<0.001), and had more previous depressive episodes (chi2=27.35, df=1, p<0.001). Our data suggest that there is an association between respiratory PD subtype and hyperreactivity to challenge tests: CO2 and oral caffeine.
Source : Hum Psychopharmacol 2007 vol.22 Issue 4 pp 231 - 240
Coffee drinking enhances the analgesic effect of cigarette smoking
Nastase, A.; Ioan, S.; Braga, R. I.; Zagrean, L.; Moldovan, M.
Nicotine (from cigarette smoke) and caffeine (from coffee) have analgesic effects in humans and experimental animals. We investigated the combined effects of coffee drinking and cigarette smoking on pain experience in a group of moderate nicotine-dependent, coffee drinking, young smokers. Pain threshold and pain tolerance were measured during cold pressor test following the habitual nocturnal deprivation of smoking and coffee drinking. Smoking increased pain threshold and pain tolerance in both men and women. Coffee drinking, at a dose that had no independent effect, doubled the increase in pain threshold induced by smoking. The effect could not be explained by a cumulative raise in blood pressure. Our data suggest that caffeine enhances the analgesic effect of nicotine.
Source : Neuroreport 2007 vol.18 (9), pp 921 - 924
Clinical importance of caffeine dependence and abuse
Ogawa, N.; Ueki, H.
Caffeine is the most widely consumed psychoactive substance and is a legal stimulant that is readily available to children. Caffeine has occasionally been considered a drug of abuse and the potential for dependence on caffeine has been debated. Presently, due to a paucity of clinical evidence on caffeine dependence or abuse, no such diagnosis is included in the Diagnostic and Statistical Manual of Mental Disorder-fourth edition. The authors present two cases of abuse or dependence on the caffeine contained in 'eutrophic' (energy/nutritional) beverages or caffeine preparations, followed by a review of clinical studies demonstrating evidence that some people can manifest a clinical syndrome of caffeine dependence or abuse. The cases suggest that caffeine can produce a clinical dependence syndrome similar to those produced by other psychoactive substances and has a potential for abuse. In a recent study using a structured interview and the Diagnostic and Statistical Manual of Mental Disorder-fourth edition criteria for substance dependence and abuse, a subset of the general population was found to demonstrate caffeine dependence or caffeine abuse. Therefore, the authors propose that companies or businesses manufacturing or marketing caffeine or products containing caffeine must meet the following guidelines: (i) clearly indicate the caffeine content of products containing comparatively higher quantities of caffeine; (ii) warn that such products should be avoided by infants and children wherever possible, and inform adult consumers about the precise quantity of caffeine that is considered safe for consumption; and (iii) clearly state that consuming large quantities of caffeine and the long-term use of caffeine carry health risks.
Source : Psychiatry Clin Neurosci 2007 vol.61 (3), pp 263 - 268
Synthesis of hybrid molecules of caffeine and eudistomin D and its effects on adenosine receptors
Ohshita, K.; Ishiyama, H.; Oyanagi, K.; Nakata, H.; Kobayashi, J.
Four hybrid molecules (1 and 12-14) of caffeine and eudistomin D, a beta-carboline alkaloid from a marine tunicate, were synthesized, and their affinity and selectivity for adenosine receptors A(1), A(2A), and A(3) were examined. It was found that all the compounds showed better potency as adenosine receptor ligands as compared with caffeine. Among them, a compound (13) possessing a nitrogen at the delta-position of the pyridine ring (delta-N type) showed the most potent affinity for adenosine receptor A(3) subtype, while N-methylation (14) of a pyrrole ring in 13 significantly lowered the potency as adenosine receptor ligands. Compounds (1 and 12) having a nitrogen at the beta-position of the pyridine ring (beta-N type) showed lower affinity than the corresponding delta-N type compounds (13 and 14), while compounds (10, 11, and 17) lacking a pyrrole ring between the pyridine and pyrimidine rings exhibited almost no affinity to the adenosine receptor subtypes examined.
Source : Bioorg Med Chem 2007 vol.15 (9), pp 3235 - 3240
Follicular penetration of topically applied caffeine via a shampoo formulation
Otberg, N.; Teichmann, A.; Rasuljev, U.; Sinkgraven, R.; Sterry, W.; Lademann, J.
Follicular drug delivery is the prerequisite for an effective treatment of androgenetic alopecia or other reasons of premature hair loss. METHODS: The follicular penetration of caffeine, applied topically in a shampoo formulation for 2 min, was measured with highly sensitive surface ionization in combination with mass spectroscopy, a selective method for the detection of very small quantities of transcutaneously absorbed substances in the blood. An experimental protocol, developed to selectively block the follicular pathway within the test area, was used. Based on this principle, a clear distinction between interfollicular and follicular penetration of topically applied caffeine was feasible. RESULTS: After 2 min, caffeine penetrated via the hair follicles and stratum corneum.
CONCLUSION: It was found that the penetration via hair follicles was faster and higher compared with the interfollicular route and that hair follicles are the only pathway for fast caffeine absorption during the first 20 min after application.
Source : Skin Pharmacol Physiol 2007 vol.20 (4), pp 195 - 198
Non-alcoholic beverage and caffeine consumption and mortality: the Leisure World Cohort Study
Paganini-Hill, A.; Kawas, C. H.; Corrada, M. M.
To examine the effects of non-alcoholic beverage and caffeine consumption on all-cause mortality in older adults. METHODS: The Leisure World Cohort Study is a prospective study of residents of a California retirement community. A baseline postal health survey included details on coffee, tea, milk, soft drink, and chocolate consumption. Participants were followed for 23 years (1981-2004). Risk ratios (RRs) of death were calculated using Cox regression for 8644 women and 4980 men (median age at entry, 74 years) and adjusted for age, gender, and multiple potential confounders. RESULTS: Caffeine consumption exhibited a U-shaped mortality curve. Moderate caffeine consumers had a significantly reduced risk of death (multivariable-adjusted RR=0.94, 95% CI: 0.89, 0.99 for 100-199 mg/day and RR=0.90, 95% CI: 0.85, 0.94 for 200-399 mg/day compared with those consuming <50 mg/day). Individuals who drank more than 1 can/week of artificially sweetened (but not sugar-sweetened) soft drink (cola and other) had an 8% increased risk (95% CI: 1.01-1.16). Neither milk nor tea had a significant effect on mortality after multivariable adjustment.
CONCLUSIONS: Moderate caffeine consumption appeared beneficial in reducing risk of death. Attenuation in the observed associations between mortality and intake of tea and milk with adjustment for potential confounders suggests that such consumption identifies those with other mortality-associated lifestyle and health risks. The increased death risk with consumption of artificially sweetened, but not sugar-sweetened, soft drinks suggests an effect of the sweetener rather than other components of the soft drinks, although residual confounding remains a possibility.
Source : Prev Med 2007 vol.44 (4), pp 305 - 310
Strong combined gene-environment effects in anti-cyclic citrullinated peptide-positive rheumatoid arthritis: a nationwide case-control study in Denmark
Pedersen, M.; Jacobsen, S.; Garred, P.; Madsen, H. O.; Klarlund, M.; Svejgaard, A.; Pedersen, B. V.; Wohlfahrt, J.; Frisch, M.
To study the role of shared epitope (SE) susceptibility genes, alone and in combination with tobacco smoking and other environmental risk factors, for risk of subtypes of rheumatoid arthritis (RA) defined by the presence or absence of serum antibodies against cyclic citrullinated peptides (CCPs). METHODS: To address these issues, a nationwide case-control study was conducted in Denmark during 2002-2004, comprising incident cases of RA or patients with recently diagnosed RA (309 seropositive and 136 seronegative for IgG antibodies against CCP) and 533 sex- and age-matched population controls. Associations were evaluated by logistic regression analyses, in which odds ratios (ORs) served as measures of relative risk. RESULTS: Compared with individuals without SE susceptibility genes, SE homozygotes had an elevated risk of anti-CCP-positive RA (OR 17.8, 95% confidence interval [95% CI] 10.8-29.4) but not anti-CCP-negative RA (OR 1.07, 95% CI 0.53-2.18). Strong combined geneenvironment effects were observed, with markedly increased risks of anti-CCP-positive RA in SE homozygotes who were heavy smokers (OR 52.6, 95% CI 18.0-154), heavy coffee drinkers (OR 53.3, 95% CI 15.5-183), or oral contraceptive users (OR 44.6, 95% CI 15.2-131) compared with SE noncarriers who were not exposed to these environmental risk factors.
CONCLUSION: Persons who are homozygous for SE susceptibility genes, notably those who are also exposed to environmental risk factors, have a markedly and selectively increased risk of anti-CCP-positive RA. A distinction between anti-CCP-positive RA and anti-CCP-negative RA seems warranted, because these RA subtypes most likely represent etiologically distinct disease entities.
Source : Arthritis Rheum 2007 vol.56 (5), pp 1446 - 1453
Liquid chromatography/electrospray ionization tandem mass spectrometry assay for determination of nicotine and metabolites, caffeine and arecoline in breast milk
Pellegrini, M.; Marchei, E.; Rossi, S.; Vagnarelli, F.; Durgbanshi, A.; Garcia-Algar, O.; Vall, O.; Pichini, S.
A procedure based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described for the determination of nicotine and its principal metabolites cotinine, trans-3-hydroxycotinine and cotinine-Noxide, caffeine and arecoline in breast milk, using N-ethylnorcotinine as internal standard. Liquid/liquid extraction with chloroform/isopropanol (95:5, v/v) was used for nicotine, cotinine, trans-3-hydroxycotinine, cotinine-N-oxide and caffeine under neutral conditions and for arecoline under basic conditions. Chromatography was performed on a C(8) reversed-phase column using a gradient of 50 mM ammonium formate, pH 5.0, and acetonitrile as a mobile phase at a flow rate of 0.5 mL/min. Separated analytes were determined by electrospray ionization tandem mass spectrometry in the positive ion mode using multiple reaction monitoring. Limits of quantification were 5 microg/L for nicotine, cotinine, trans-3-hydroxycotinine, cotinine-N-oxide and caffeine, and 50 microg/L for arecoline using 1 mL human milk per assay. Calibration curves were linear over the calibration ranges for all the substances under investigation, with a minimum r(2) > 0.998. At three concentrations spanning the linear dynamic range of the assay, mean recoveries from breast milk ranged between 71.8 and 77.4% for different analytes. This method was applied to the analysis of analytes in human milk to assess substance exposure in breast-fed infants in relation to eventual clinical outcomes. This LC/MS/MS assay provides adequate sensitivity and performance characteristics for the simultaneous quantification of biomarkers of three of the drugs most commonly used worldwide (tobacco, caffeine and areca nut).
Source : Rapid Commun Mass Spectrom 2007 vol.21 (16), pp 2693 - 2703
Caffeine accelerates absorption and enhances the analgesic effect of acetaminophen
Renner, B.; Clarke, G.; Grattan, T.; Beisel, A.; Mueller, C.; Werner, U.; Kobal, G.; Brune, K.
The aim of this study was to determine the analgesic effect of acetaminophen compared to a combination of both caffeine and acetaminophen or caffeine alone using tonic and phasic pain stimulation. Twenty-four subjects were treated orally with 1000 mg acetaminophen, 130 mg caffeine, and a combination of both in a 4-way crossover, double-blind, placebo-controlled study. Pharmacokinetics and analgesic effects were assessed by means of an experimental pain model based on pain-related cortical potentials after phasic stimulation of the nasal mucosa with CO(2) and based on pain ratings after tonic stimulation with dry air. Analgesic effects of acetaminophen and acetaminophen plus caffeine but not caffeine alone caused a significant reduction of pain-related cortical potentials beginning 30 minutes after medication. The combination demonstrated an enhanced effect throughout the observation time up to 3 hours. Caffeine accelerated acetaminophen absorption, indicated by enhanced early AUCs. Significant analgesic effects of the combination on tonic pain ratings were found throughout the observation time as compared to acetaminophen and placebo. In this study, caffeine enhanced and prolonged the analgesic activity of acetaminophen.
Source : J Clin Pharmacol 2007 vol.47 (6), pp 715 - 726
The cholesterol-raising factor from coffee beans, cafestol, as an agonist ligand for the farnesoid and pregnane X receptors
Ricketts, M. L.; Boekschoten, M. V.; Kreeft, A. J.; Hooiveld, G. J.; Moen, C. J.; Muller, M.; Frants, R. R.; Kasanmoentalib, S.; Post, S. M.; Princen, H. M.; Porter, J. G.; Katan, M. B.; Hofker, M. H.; Moore, D. D.
Cafestol, a diterpene present in unfiltered coffee brews such as Scandinavian boiled, Turkish, and cafetiere coffee, is the most potent cholesterol-elevating compound known in the human diet. Several genes involved in cholesterol homeostasis have previously been shown to be targets of cafestol, including cholesterol 7alpha-hydroxylase (CYP7A1), the rate-limiting enzyme in bile acid biosynthesis. We have examined the mechanism by which cafestol elevates serum lipid levels. Changes in several lipid parameters were observed in cafestol-treated APOE3Leiden mice, including a significant increase in serum triglyceride levels. Microarray analysis of these mice identified alterations in hepatic expression of genes involved in lipid metabolism and detoxification, many of which are regulated by the nuclear hormone receptors farnesoid X receptor (FXR) and pregnane X receptor (PXR). Further studies demonstrate that cafestol is an agonist ligand for FXR and PXR, and that cafestol down-regulates expression of the bile acid homeostatic genes CYP7A1, sterol 12alpha-hydroxylase, and Na(+)- taurocholate cotransporting polypeptide in the liver of wild-type but not FXR null mice. Cafestol did not affect genes known to be up-regulated by FXR in the liver of wild-type mice, but did increase expression of the positive FXR-target genes intestinal bile acid-binding protein and fibroblast growth factor 15 (FGF15) in the intestine. Because FGF15 has recently been shown to function in an enterohepatic regulatory pathway to repress liver expression of bile acid homeostatic genes, its direct induction in the gut may account for indirect effects of cafestol on liver gene expression. PXR-dependent gene regulation of cytochrome P450 3A11 and other targets by cafestol was also only seen in the intestine. Using a double FXR/PXR knockout mouse model, we found that both receptors contribute to the cafestol dependent induction of intestinal FGF15 gene expression. In conclusion, cafestol acts as an agonist ligand for both FXR and PXR, and this may contribute to its impact on cholesterol homeostasis.
Source : Mol Endocrinol 2007 vol.21 (7), pp 1603 - 1616
The 1976C>T polymorphism in the adenosine A2A receptor gene does not affect the vasodilator response to adenosine in humans in vivo
Riksen, N. P.; Franke, B.; van den Broek, P.; Smits, P.; Rongen, G. A.
The 1976C>T polymorphism in the adenosine A2A receptor gene (ADORA2A) modulates the psychological response to administration of the adenosine receptor antagonist caffeine. We quantified the vascular response to adenosine and caffeine to determine the relevance of this variant allele in the physiological response to these agents. We selected 10 study participants with the TT genotype and 10 CC controls, matched for activities of other proteins involved in the metabolism of adenosine. The vasodilator response to the intrabrachial administration of adenosine (0.5, 1.5, 5.0, 15.0, and 50.0 microg/min/dl; venous occlusion plethysmography) was not different between the groups (P=0.4). In addition, the effect of subsequent administration of caffeine (90 microg/min/dl) was not different (P=0.7). We conclude that the 1976C>T polymorphism does not affect the vascular response to adenosine and caffeine in humans in vivo. Therefore, this polymorphism does not contribute to the variation in the effects of adenosine receptor stimulation.
Source : Pharmacogenet.Genomics 2007 vol.17 (7), pp 551 - 554
The neuroprotective effects of caffeine: a prospective population study (the Three City Study)
Ritchie, K.; Carriere, I.; de Mendonca, A.; Portet, F.; Dartigues, J. F.; Rouaud, O.; Barberger-Gateau, P.; Ancelin, M. L.
OBJECTIVE : To examine the association between caffeine intake, cognitive decline, and incident dementia in a community-based sample of subjects aged 65 years and over. METHODS: Participants were 4,197 women and 2,820 men from a population-based cohort recruited from three French cities. Cognitive performance, clinical diagnosis of dementia, and caffeine consumption were evaluated at baseline and at 2 and 4 year follow-up. RESULTS: Caffeine consumption is associated with a wide range of sociodemographic, lifestyle, and clinical variables which may also affect cognitive decline. Multivariate mixed models and multivariate adjusted logistic regression indicated that women with high rates of caffeine consumption (over three cups per day) showed less decline in verbal retrieval (OR = 0.67, CI = 0.53, 0.85), and to a lesser extent in visuospatial memory (OR = 0.82, CI = 0.65, 1.03) over 4 years than women consuming one cup or less. The protective effect of caffeine was observed to increase with age (OR = 0.73, CI = 0.53, 1.02 in the age range 65 to 74; OR = 0.3, CI = 0.14, 0.63 in the range 80+). No relation was found between caffeine intake and cognitive decline in men. Caffeine consumption did not reduce dementia risk over 4 years.
CONCLUSIONS: The psychostimulant properties of caffeine appear to reduce cognitive decline in women without dementia, especially at higher ages. Although no impact is observed on dementia incidence, further studies are required to ascertain whether caffeine may nonetheless be of potential use in prolonging the period of mild cognitive impairment in women prior to a diagnosis of dementia.
Source : Neurology 2007 vol.69 (6), pp 536 - 545
Caffeine restores regional brain activation in acute hypoglycaemia in healthy volunteers
Rosenthal, M. J.; Smith, D.; Yaguez, L.; Giampietro, V.; Kerr, D.; Bullmore, E.; Brammer, M.; Williams, S. C.; Amiel, S. A.
Caffeine enhances counterregulatory responses to acute hypoglycaemia. Our aim was to explore its effects on cortical function, which are not known at present. Methods Regional brain activation during performance of the four-choice reaction time (4CRT) at different levels of complexity was measured using functional magnetic resonance imaging (fMRI) at euglycaemia (5 mmol/l) and hypoglycaemia (2.6 mmol/l) in the presence and absence of caffeine in six healthy right-handed men. Results During hypoglycaemia, caffeine enhanced adrenaline responses to hypoglycaemia (2.5 +/- 0.7 nmol/l to 4.0 +/- 1.0 nmol/l, P = 0.01) and restored the brain activation response to the non-cued 4CRT, the linear increases in regional brain activation associated with increased task complexity and the ability to respond to a cue that were lost in hypoglycaemia alone.
CONCLUSIONS : Caffeine can sustain regional brain activation patterns lost in acute hypoglycaemia, with some restoration of cortical function and enhanced adrenaline responsiveness. A methodology has been established that may help in the development of therapies to protect against severe hypoglycaemia in insulin therapy for patients with diabetes and problematic hypoglycaemia.
Source : Diabet Med 2007 vol.24 (7), pp 720 - 727
Caffeine and headaches
Shapiro, R. E.
Caffeine is the most widely consumed psychostimulant drug. It is a potent antagonist of adenosine receptors at dosages consistent with common dietary intake. With infrequent exposure, caffeine may act as an analgesic for headache or an adjuvant for the actions of other analgesics. With chronic repetitive intake, caffeine is associated with an increased risk of development of analgesicoveruse headache, chronic daily headache and physical dependency. Cessation of caffeine use following chronic exposures leads to a withdrawal syndrome, with headache as a dominant symptom.
Source : Neurol Sci 2007 vol.28 Suppl 2, pp S179 - S183
Intake of coffee and tea and risk of ovarian cancer: a prospective cohort study
Silvera, S.-A. N.; Jain, M.; Howe, G. R.; Miller, A. B.; Rohan, T. E.
There is some evidence from case-control studies that coffee consumption might be positively associated with ovarian cancer risk, whereas the epidemiologic evidence regarding tea consumption and ovarian cancer is inconsistent. To date, there have been few prospective studies of these associations. Therefore, this study examined ovarian cancer risk in association with both coffee and tea intake in a prospective cohort study of 49 613 Canadian women enrolled in the National Breast Screening Study (NBSS) who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the food frequency questionnaire were used to estimate daily intake of coffee and tea. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between categories of coffee and tea intake and ovarian cancer risk. During a mean 16.4 yr of follow-up, 264 incident ovarian cancer cases were observed. Tea intake was not associated with ovarian cancer risk in our study population. In contrast, a borderline positive association was observed among women who drank >4 cups coffee/day compared to women who did not drink coffee (HR = 1.62, 95% CI = 0.95-2.75, Ptrend = 0.06). Given the pervasive use of these beverages, the associations between coffee and tea consumption and ovarian cancer risk warrant investigation in further prospective studies.
Source : Nutrition and Cancer 2007 vol.58(1), pp 22 - 27
Formation of the thiocyanate conjugate of chlorogenic acid in coffee under acidic conditions in the presence of thiocyanate and nitrite: possible occurrence in the stomach
Takahama, U.; Tanaka, M.; Oniki, T.; Hirota, S.; Yamauchi, R.
The objective of the present study was to elucidate how chlorogenic acid in coffee was transformed under acidic conditions simulating the mixture of saliva and gastric juice. When coffee was incubated in acidified saliva that contained nitrite and SCN-, in addition to nitric oxide (NO), 4 major components were detected. 2 of the 4 components (components 3 and 4) were generated when chlorogenic acid was incubated in acidified saliva and when incubated in an acidic buffer solution in the presence of both nitrite and SCN-. By the incubation of chlorogenic acid in acidic nitrite in the absence of SCN-, components 3 and 4 were not formed but the quinone of chlorogenic acid and nitrated chlorogenic acid were formed. The result indicates that SCN- was indispensable for nitrous acid induced formation of components 3 and 4. Component 4 was isolated and its structure was determined to be (E)-5'-(3-(7-hydroxy-2-oxobenzo[d] [1,3]oxathiol-4-yl)acryloyloxy)quinic acid. Component 3, which was suggested to be 2-thiocyanatochlorogenic acid, seemed to be formed by the reaction between SCN- and the quinone of chlorogenic acid. As it has been reported that the quinone of chlorogenic acid can react with thiols and can decompose producing H2O2, the formation of component 4 can reduce the toxic effects of the quinone of chlorogenic acid.
Source : J Agric Food Chem 2007 vol.55(10), pp 4169 - 4176
Effects of postnatal caffeine exposure on seizure susceptibility in developing rats
Tchekalarova, J.; Kubova, H.; Mares, P.
Postnatal caffeine treatment of rats can influence brain excitability during development. To study the mechanism involved in the alterations of seizure susceptibility, we used an animal model that corresponds to the infants treated with caffeine for apnea of prematurity. Seizure susceptibility to four convulsant drugs (pentetrazol, picrotoxin, bicuculline and aminophylline) was assessed in 12- and 25-day-old rats exposed to caffeine at a daily dose of 10 and/or 20 mg/kg s.c. at postnatal days 7-11. Our results demonstrated that the changes in generalized tonic-clonic seizures (GTCS) are more expressed than changes in minimal clonic seizures. There are marked differences among individual convulsants with the highest sensitivity of aminophylline-induced seizures and nearly complete resistance of bicuculline-induced seizures. The changes in individual models are age specific: aminophylline- and picrotoxin-induced seizures are more affected in 12- than in 25-day-old rats whereas PTZ-induced seizures are more changed by early postnatal caffeine exposure in 25- than in 12-day-old animal. Taken together, repeated caffeine treatment from postnatal day 7 to 11 reduces the seizure susceptibility during development and this reduction is also model specific.
Source : Brain Res 2007 vol.1150, pp 32 - 39
Coffee intake and incidence of hypertension
Uiterwaal, C.-S. P. M.; Verschuren, W.-M. M.; Bueno-de-Mesquita, H. B.; Ocke, M.; Geleijnse, J. M.; Boshuizen, H. C.; Peeters, P.-H. M.; Feskens, E.-J. M.; Grobbee, D. E.
The long-term longitudinal evidence for a relationship between coffee intake and hypertension is relatively scarce. The objective of this study was to assess whether coffee intake is associated with the incidence of hypertension. Coffee abstainers at baseline had a lower risk of hypertension than did those with a coffee intake of >0-3 cups/day (odds ratio (OR): 0.54; 95% confidence interval (CI): 0.31, 0.92). Women who drank >6 cups/day had a lower risk than did women who drank >0-3 cups/day (OR: 0.67; 95% CI: 0.46, 0.98). Subjects aged <greater than or equal to>39 yrs at baseline had 0.35 mm Hg (95% CI: -0.59, -0.11 mm Hg) lower SBP per cup intake/day and 0.11 mm Hg lower DBP (95% CI: -0.26, 0.03 mm Hg) than did those aged <39 yrs at baseline, although the difference in DBP was not statistically significant. Results suggest that coffee abstinence is associated with a lower hypertension risk than is low coffee consumption. An inverse U-shaped relation between coffee intake and risk of hypertension was observed in women.
Source : Am J Clin Nutri 2007 vol.85(3), pp 718 - 723
Effect of caffeine on microsurgical technical performance
Urso-Baiarda, F.; Shurey, S.; Grobbelaar, A. O.
Microsurgeons may choose to avoid caffeine to prevent potentially deleterious caffeine tremor, although an adverse effect on surgical skill has never been shown. This double-blind placebo-controlled crossover study investigated the effect of moderate caffeine intake on microsurgical ability among microsurgical training course attendees. Subjects were randomized to receive either morning placebo and afternoon caffeine, or the reverse, thereby acting as their own controls. Performance in end-to-end vessel anastomosis was graded by a single observer during both sessions using a global rating scale. Subjects consuming caffeine in the morning demonstrated significantly improved scores from morning to afternoon, whereas subjects consuming caffeine in the afternoon showed no such improvement. These results are consistent with an adverse effect of caffeine on microsurgical skill combined with a learning curve among the study population of novice microsurgeons, and support the view that caffeine has a detrimental effect on microsurgical ability among this study group.
Source : Microsurgery 2007 vol.27 (2), pp 84 - 87
Extract of Hypericum perforatum blocks caffeine-induced locomotor activity in mice: a possible role of nitric oxide
Uzbay, I. T.; Coskun, I.; Kayir, H.; Ozturk, N.; Ozturk, Y.
The present study investigated the effects of HPE on caffeine-induced locomotor activity in mice. Caffeine (4-16 mg/kg) or saline were given to adult male Swiss-Webster mice, and the locomotor activity was immediately measured for 30 min. HPE (6-48 mg/kg) and saline were injected to another group of mice and the locomotor activity was measured 20 min later. HPE (6-24 mg/kg) was also administered to another group of mice 20 min before caffeine (16 mg/kg) injections and the locomotor activity was recorded for 30 min immediately after caffeine administrations. Finally l-arginine (1 g/kg) was administered i.p. 20 min before HPE (6 mg/kg) and the locomotor activity was measured as mentioned above. Each group of mice was used only once. Caffeine produced some significant increases in locomotor activity of the mice. HPE (6-24 mg/kg) significantly blocked the caffeine-induced locomotor hyperactivity. Pretreatment of l-arginine (1 g/kg) reversed the inhibitory effect of HPE (6 mg/kg) on caffeine-induced locomotor activity without producing any significant effect on locomotor activity of the mice when it was administered alone. The results suggest that HPE blocks caffeine-induced locomotor hyperactivity in mice. Furthermore, the inhibitory effect of HPE on caffeine-induced locomotor activity may be related to its NOS inhibitory property.
Source : Phytother Res 2007 vol.21 (5), pp 415 - 419
Inhibition of monoamine oxidase B by selected benzimidazole and caffeine analogues
van den Berg, D.; Zoellner, K. R.; Ogunrombi, M. O.; Malan, S. F.; Terre'Blanche, G.; Castagnoli, N. Jr; Bergh, J. J.; Petzer, J. P.
We have recently reported that a series of (E)-8-styrylcaffeines and (E)-2-styrylbenzimidazoles are moderate to very potent competitive inhibitors of monoamine oxidase B (MAO-B). The most potent member of the series was found to be (E)-8-(3-chlorostyryl)caffeine (CSC) with an enzyme-inhibitor dissociation constant (K(i) value) of 128 nM. In the present study, we have prepared additional caffeine and benzimidazole analogues in an attempt to identify compounds with improved MAO-B inhibition potency while still acting reversibly. The most potent inhibitor among the caffeine analogues was (E)-8-(3,4-dichlorostyryl)caffeine with a K(i) value of 36 nM, approximately 3.5 times more potent than CSC. The most potent inhibitor among the benzimidazole analogues was (E)-2-(4-trifluoromethylstyryl)-1-methylbenzimidazole with a K(i) value of 430 nM. An SAR analysis indicated that the potency of MAO-B inhibition by (E)-2-styryl-1-methylbenzimidazole analogues depended upon the Taft steric parameter (E(s)) of the substituents attached to C-4 of the styryl phenyl ring. Substituents with a large degree of steric hindrance appear to enhance inhibition potency. The proposal that potent MAO-B inhibition by (E)-8-styrylcaffeines and (E)-2-styrylbenzimidazoles can be explained by a mode of binding that involves traversing both the entrance and substrate cavities was supported by the finding that 1-methylbenzimidazole only weakly inhibited MAO-B with a K(i) value of 2084 microM. Without the styryl side chain, 1-methylbenzimidazole is not expected to be able to bind simultaneously to both the entrance and substrate cavities.
Source : Bioorg Med Chem 2007 vol.15 (11), pp 3692 - 3702
Effect of caffeine on quinidine transport to the central nervous system in rats
Vasovic, V.; Banic, B.; Jakovljevic, V.
We studied the effect of caffeine on the transport of quinidine through the blood-brain barrier (BBB) to the central nervous system (CNS) in rats. The anesthetized animals received quinidine in the form of a retrograde intra-arterial bolus injection (15 s) into the right axillary artery 30 min after receiving a subcutaneous injection of caffeine (test group) or physiological solution (control group). Rats were decapitated at 30, 60, 90, 120, and 240 s after quinidine administration. Blood samples were taken from the left jugular vein. Upon washing, the brain, was divided into the brainstem, cerebellum, and cerebral hemispheres to determine the quinidine content in each section, using a standard spectrofluorimetric method. Quninidine attained maximal concentrations in the CNS with a latency compared with that in blood; the CNS values were higher. Quinidine kinetics showed two compartments in the CNS, one consisting of the brainstem and cerebellum, in which quinidine concentrations were higher, and the other the cerebral hemispheres. Caffeine caused a significant deceleration of quinidine transition through the BBB to the CNS.
Source : J Basic Clin Physiol Pharmacol 2007 vol.18 (1), pp 1 - 10 (not available on line)
Effect of chronic coffee consumption on aortic stiffness and wave reflections in hypertensive patients
Vlachopoulos, C. V.; Alexopoulos, N. A.
Aortic stiffness and wave reflections are important markers and prognosticators of cardiovascular risk. Caffeine increases acutely aortic stiffness and wave reflections. Furthermore, chronic coffee consumption is associated with increased aortic stiffness and wave reflections in normotensive subjects. This study assessed the association between chronic coffee consumption and aortic stiffness and wave reflections in hypertensive patients. 259 never-treated hypertensives (age 50 ± 12 yr, 165 males) without diabetes mellitus, who were asked to describe in detail the type and amount of coffee they consumed, were examined. Carotid-femoral pulse wave velocity (PWV) and augmentation index (AIx) were measured noninvasively as indices of aortic stiffness and wave reflections, respectively. Results showed that when controlled for gender, age, height, smoking status, heart rate, mean pressure, high density lipoprotein cholesterol and hsCRP, AIx was found to be higher with increasing daily coffee consumption. Post hoc analysis revealed that all groups of coffee consumption had higher AIx compared to no-consumption. PWV did not differ among groups of daily coffee consumption. Each participant had 35% higher relative risk of having high AIx for each cup (150 ml) of coffee per day, and 40% higher relative risk for each 10 cup-yr. It is concluded that coffee consumption is associated with increased wave reflections, but not aortic stiffness in never-treated hypertensive patients. This finding may have important clinical implications for cardiovascular health in hypertensive subjects.
Source : Eur J Clin Nutr 2007 vol.61(6), pp 796 - 802
Liver cancer risk, coffee, and hepatitis C virus infection: a nested case-control study in Japan
Wakai, K.; Kurozawa, Y.; Shibata, A.; Fujita, Y.; Kotani, K.; Ogimoto, I.; Naito, M.; Nishio, K.; Suzuki, H.; Yoshimura, T.; Tamakoshi, A.
We examined hepatocellular carcinoma mortality in relation to coffee consumption and anti-hepatitis C virus (HCV) antibody seropositivity in a nested case-control study involving 96 cases. The multivariateadjusted odds ratios (95% confidence interval) for daily coffee drinkers vs non-drinkers were 0.49 (0.25-0.96), 0.31 (0.11-0.85), and 0.75 (0.29-1.92) in all cases, in HCV-positive and in HCV-negative individuals, respectively.British Journal of Cancer (2007) 97, 426-428. doi:10.1038/sj.bjc.6603891 www.bjcancer.com Published online 17 July 2007.
Source : Br J Cancer 2007 vol.97 (3), pp 426 - 428
Caffeine attenuates the duration of coronary vasodilation and changes in hemodynamics induced by regadenoson (CVT-3146), a novel adenosine A2A receptor agonist
Zhao, G.; Messina, E.; Xu, X.; Ochoa, M.; Sun, H. L.; Leung, K.; Shryock, J.; Belardinelli, L.; Hintze, T. H.
Effects of caffeine on regadenoson-induced coronary vasodilation and changes in hemodynamics were examined in conscious dogs. Sixteen dogs were chronically instrumented for measurements of coronary blood flow (CBF), mean arterial pressure (MAP), and heart rate (HR). Regadenoson (5 microg/kg, IV) increased CBF from 34 +/- 2 to 191 +/- 7 mL/min. The duration of the 2-fold increase in CBF was 515 +/- 71 seconds. Regadenoson decreased MAP by 15 +/- 2% and increased HR by 114 +/- 14%. Regadenoson-induced maximum increases in CBF were not significantly lower in the presence of caffeine at 1, 2, 4, and 10 mg/kg (2 +/- 3, 0.7 +/- 3, 16 +/- 5, and 13 +/- 8%, respectively; all P > 0.05). Caffeine at 1, 2, 4, and 10 mg/kg significantly decreased the duration of the 2-fold increase in CBF induced by regadenoson by 17% +/- 4%, 48% +/- 8%, 62% +/- 5%, and 82% +/- 5%, respectively (all P < 0.05). Caffeine at 4 and 10 mg/kg significantly attenuated the effects of regadenoson on MAP and HR. The results indicate that 1 to 10 mg/kg caffeine dose-dependently reduced the duration, but not the peak increase of CBF caused by 5 microg/kg regadenoson.
Source : J Cardiovasc Pharmacol 2007 vol.49 (6), pp 369 - 375
Influence of sodium fluoride and caffeine on the concentration of fluoride ions, glucose, and urea in blood serum and activity of protein metabolism enzymes in rat liver
Birkner, E.; Grucka-Mamczar, E.; Zalejska-Fiolka, J.; Chlubek, D.; Kasperczyk, S.; Stawiarska-Pięta, B.; Błaszczyk, U.
The aim of the study was examining the effect of fluoride ions and caffeine administration on glucose and urea concentration in blood serum and the activity of protein metabolism enzymes and selected enzymes of the urea cycle in rat liver. The study was carried out using 18 male Sprague-Daowley rats (4.5 mo old). Rats were divided into three groups. Group I received distilled water ad libitum. Group II received 4.9 mg F−/kg body mass/d of sodium fluoride in the water, and group III received sodium fluoride (in the above-mentioned dose) and 3 mg/kg body mass/d of caffeine in the water. After 50 d, the rats were anesthetized with thiopental and fluoride ions, glucose, and urea concentration in blood serum were determined. Also determined were the activities of aspartate aminotransferase, alanine aminotransferase glutamate dehydrogenase, ornithine carbamoylotransferase and arginase in liver homogenates. Liver was taken for pathomorphological examinations. The applied doses of F− (4.9 mg/kg body mass/d) and F−+ caffeine (4.9 mg F−/kg body mass/d+3 mg caffeine/kg body mass/d) resulted in a statistically significant increase of fluoride ion concentration in blood serum, a slight increase of the glucose concentration, and no changes in the concentration of urea in blood serum. This might testify to the absence of kidney lesions for the applied concentrations of F−. No change in the functioning of hepatocytes was observed; however, slight disturbances have been noted in the functioning of the liver, connected with the activation of urea cycle, increase of arginase activity, and accumulation of F− in this organ. There was no observed significant influence of caffeine supplementation on the obtained results.
Source : Biological Trace Element Research 2006 vol. 112 (2), pp 169-174
Multinutrient supplement containing ephedra and caffeine causes weight loss and improves metabolic risk factors in obese women: a randomized controlled trial
Hackman, R. M.; Havel, P. J.; Schwartz, H. J.; Rutledge, J. C.; Watnik, M. R.; Noceti, E. M.; Stohs, S. J.; Stern, J. S.; Keen, C. L.
To determine the safety and efficacy of a dietary supplement with a low dose of ephedra and caffeine in overweight/obese premenopausal female subjects. DESIGN: A 9-month, double-blind, randomized control study compared the efficacy and safety of a dietary supplement with ephedra and caffeine to a control supplement. SUBJECTS: Sixty-one healthy, premenopausal women with body mass index (BMI) from 27 to 39 kg/m2 were randomly assigned and received a dietary supplement (40 mg/day ephedra alkaloids, 100 mg/day caffeine, high potency mixture of vitamins, minerals, omega-3 fatty acids) or a control supplement for 9 months. MEASUREMENTS: Efficacy: changes in body weight, body composition, lipids, insulin, leptin, adiponectin, ghrelin, and self-reports of physical activity, diet and quality of life indices. Safety: blood pressure, heart rate, electrocardiograms, urinalysis, blood histology, serum chemistry measures and self-reported symptoms. RESULTS: Forty-one women completed the study. The treatment group lost significantly more body weight (-7.18 kg) and body fat (-5.33 kg) than the control group (-2.25 and -0.99 kg, respectively), and showed significant declines in heart rate, serum cholesterol, triglycerides, cholesterol to high-density lipoprotein ratio, glucose, fasting insulin, and leptin. Blood pressure, electrocardiograms, other clinical chemistry measures, blood histology, urinalysis, and self reported physical activity were similar in the groups. Minor symptoms included dry mouth, insomnia, nervousness and palpitations. The treatment group reported more energy and decreased appetite compared to controls and scored higher on a quality of life domain assessing vitality.
CONCLUSION: A dietary supplement containing a low potency ephedra/caffeine mixture appeared safe and effective in causing loss of weight and body fat, and improving several metabolic parameters, including insulin sensitivity and lipid profiles when tested under physician supervision. Such supplements could be a useful tool to assist with weight loss.
Source : Int J Obes (Lond) 2006 vol.30 (10), pp 1545 - 1556
Differences in microbiological composition of saliva and dental plaque in subjects with different drinking habits
Signoretto, C.; Burlacchini, G.; Bianchi, F.; Cavalleri, G.; Canepari, P.
Several foods have been shown to contain natural components (especially polyphenols) which display anti-adhesive properties against Streptococcus mutans, the aetiological agent responsible for dental crown caries, as well as inhibition of glucosyltransferases, which are the S. mutans enzymes involved in the synthesis of an adherent, water-insoluble glucan from sucrose. Other studies have demonstrated an in vitro action on oral plaque biofilm formation and desorption. This study evaluated whether the activity displayed in vitro by drink compounds could affect the microbiological composition of saliva and dental plaque of subjects with a diet rich in these drinks, comparing the results with those obtained from subjects with a different diet. The beverages considered were coffee, barley coffee, tea and wine. A total of 93 subjects were recruited into the study. 6 samples of both plaque and saliva were collected from each subject at roughly 1-monthly intervals. Total bacteria, total streptococci, S. mutans and Lactobacillus counts were determined by culture in both saliva and dental plaque. The highest bacterial titres were recorded for the control population, while each drinking habit subgroup showed counts roughly one log lower than the controls. These differences in bacterial counts proved statistically significant (P < 0.05). As far as dental plaque was concerned, while total counts did not significantly vary per mg of plaque in the subjects belonging to the different drinking habit subgroups, a significant decrease (P < 0.05) was observed in those subjects drinking coffee, tea, barley coffee and wine when mutans streptococci and lactobacilli were evaluated. In several cases a >1 log decrease was observed. Plaque indices were also determined, and a significant (P < 0.05) reduction in values was recorded in the subjects belonging the specific drinking habit subgroups compared to the control group. Results suggest that a correlation exists between consumption of specific foods and oral health in terms of reduced plaque deposition and lower counts of odontopathogens.
Source : Microbiologica.2006 vol.29(4), 4 pp 293 - 302
Acute effects of caffeine and tobacco on arterial function and wave travel
Swampillai, J.; Rakebrandt, F.; Morris, K.; Jones, C. J.; Fraser, A. G.
Caffeine and tobacco consumption are risk factors for heart failure, but their effects remain controversial. It has been hypothesized that they cause alterations in arterial stiffness and arterial wave travel which may increase ventricular loading. In this study the authors examined the influence of these widely used stimulants on wave intensity and arterial stiffness parameters using carotid wave intensity analysis. MATERIALS AND METHODS: A new Doppler-based ultrasound method was used to measure the acute effects of caffeine and tobacco on wave intensity in the right common carotid artery. The measurements enabled changes in arterial stiffness parameters to be recorded. RESULTS: In 17 subjects compared with 10 controls, caffeine increased blood pressure, early systolic wave intensity and wave speed, but late-systolic wave intensity and mid-systolic reflections were unchanged. In 11 smokers studied before and after smoking one cigarette, blood pressure and arterial stiffness increased but wave intensity was unchanged. No changes were observed in the controls.
CONCLUSIONS: Increased wave intensity during ejection after caffeine suggested sympathomimetic effects on the left ventricular function. Increased wave speed in the common carotid artery implied augmented central loading after caffeine, but the absence of measurable changes in local arterial stiffness in the carotid artery suggested more complex and regional effects. Cigarette smoking acutely increased local arterial stiffness in the common carotid artery. These changes can be detected using wave intensity analysis.
Source : Eur J Clin Invest 2006 vol.36 (12), pp 844 - 849
Direct effects of caffeine on osteoblastic cells metabolism: the possible causal effect of caffeine on the formation of osteoporosis
Tsuang, Y. H.; Sun, J. S.; Chen, L. T.; Sun, S. C.; Chen, S. C.
: Caffeine consumption has been reported to decrease bone mineral density (BMD), increase the risk of hip fracture, and negatively influence calcium retention. In this study, we investigated the influence of caffeine on the osteoblasts behaviour. METHOD: Osteoblasts derived from newborn Wistar-rat calvaria was used in this study. The effects of various concentrations of caffeine on bone cell activities were evaluated by using MTT assay. Alkaline phosphatase (ALP) staining, von Kossa staining and biochemical parameters including ALP, lactate dehydrogenase (LDH), prostaglandin E2 (PGE2) and total protein were performed at day 1, 3, and 7. DNA degradation analysis under the caffeine influence was also performed. RESULTS AND DISCUSSION: The results showed that the viability of the osteoblasts, the formation of ALP positive staining colonies and mineralization nodules formation in the osteoblasts cultures decreased significantly in the presence of 10 mM caffeine. The intracellular LDH, ALP and PGE2 content decreased significantly, the LDH and PGE2 secreted into the medium increased significantly. The activation of an irreversible commitment to cell death by caffeine was clearly demonstrated by DNA ladder staining. CONCLUSION: In summary, our results suggest that caffeine has potential deleterious effect on the osteoblasts viability, which may enhance the rate of osteoblasts apoptosis.
Source : J Orthop Surg 2006 vol.1 pp 7