ASIC - ALERT - August 2008

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Coffee Science Alert n° 19

August 2008

AGRONOMY

An experimental study of habitat selection by birds in a coffee plantation

Cruz-Angon, A.; Sillett, T. S.; Greenberg, R.

Unique components of tropical habitats, such as abundant vascular epiphytes, influence the distribution of species and can contribute to the high diversity of many animal groups in the tropics. However, the role of such features in habitat selection and demography of individual species has not been established. Understanding the mechanisms of habitat selection requires both experimental manipulation of habitat structure and detailed estimation of the behavioral and demographic response of animals, e.g., changes in movement patterns and survival probabilities. Such studies have not been conducted in natural tropical forest, perhaps because of high habitat heterogeneity, high species diversity, and low abundances of potential target species. Agroforestry systems support a less diverse flora, with greater spatial homogeneity which, in turn, harbors lower overall species diversity with greater numerical dominance of common species, than natural forests. Furthermore, agroforestry systems are already extensively managed and lend themselves easily to larger scale habitat manipulations than protected natural forest. Thus, agroforestry systems provide a good model environment for beginning to understand processes underlying habitat selection in tropical forest animals. Here, we use multistate, capture-recapture models to investigate how the experimental removal of epiphytes affected monthly movement and survival probabilities of two resident bird species (Common Bush-Tanager [Chlorospingus ophthalmicus] and Golden-crowned Warbler [Basileuterus culicivorus]) in a Mexican shade coffee plantation. We established two paired plots of epiphyte removal and control. We found that Bush-Tanagers were at least five times more likely to emigrate from plots where epiphytes were removed compared to control plots. Habitatspecific movement patterns were not detected in the warbler. However, unlike the Golden-crowned Warbler, Common Bush-Tanagers depend upon epiphytes for nest sites and (seasonally) for foraging. These dispersal patterns imply that active habitat selection based on the presence or absence of epiphytes occurs in C. ophthalmicus on our study area. Survival rates did not vary with habitat in either species. Interestingly, in both species, survival was higher in the nonbreeding season, when birds were in mixed-species flocks. Movement by Common Bush-Tanagers into areas with epiphytes occurred mostly during the breeding season, when mortality-driven opportunity was greatest.

Source : Ecology 2008 vol.89 (4), pp 921 - 927

Spatial pattern and ecological process in the coffee agroforestry system

Perfecto, I.; Vandermeer, J.

The coffee agroforestry system provides an ideal platform for the study of spatial ecology. The uniform pattern of the coffee plants and shade trees allows for the study of pattern generation through intrinsic biological forces rather than extrinsic habitat patchiness. Detailed studies, focusing on a key mutualism between an ant (Azteca instabilis) and a scale insect (Coccus viridis), conducted in a 45-ha plot in a coffee agroforestry system have provided insights into (1) the quantitative evaluation of spatial pattern of the scale insect Coccus viridis on coffee bushes, (2) the mechanisms for the generation of patterns through the combination of local satellite ant nest formation and regional control from natural enemies, and (3) the consequences of the spatial pattern for the stability of predator-prey (host-parasitoid) systems, for a key coccinelid beetle preying on the scale insects and a phorid fly parasitoid parasitizing the ant.

Source : Ecology 2008 vol.89 (4), pp 915 - 920

Behavioral diversity of predatory arboreal ants in coffee agroecosystems

Philpott, S. M.; Perfecto, I.; Vandermeer, J.

Aspects of predator assemblages that alter predator effects on prey have received extensive recent attention. Among other mechanisms, differences in behavior or resource use within predator trophic levels may enhance predator effects on prey, especially if effects of each predator species differ with environmental conditions. We address whether three common ant species (Azteca instabilis F. Smith, Camponotus textor Forel, and Crematogaster spp.) are functionally unique in coffee agroecosystems, asking if each species differs in (1) cooperative foraging behavior, (2) responses to experimentally introduced herbivores, and (3) responses to pest outbreaks. Furthermore, we examined the behaviors and effects of each ant species under different conditions by varying herbivore species, herbivore size, and herbivore density and carrying out observations in different seasons. Ant species significantly differed in foraging behaviors, in effects on individual herbivores, and in responses to pest outbreaks in terms of both type and time of response to herbivores. The behaviors and effects of each ant species differed in the dry and wet seasons and for different herbivore species and sizes. Although A. instabilis generally removed more larvae and more quickly removed larvae, this was not the case under all conditions. The data presented thus support that common ant species in coffee agroecosystems are behaviorally diverse in their responses to herbivores under different conditions. We discuss the implications of these differences in ant behaviors for enhancement of predatory function in light of both multipredator effects and in terms of the potential importance of predator diversity.

Source : Environ Entomol 2008 vol.37 (1), pp 181 - 191

Caffeine inhibits UV-mediated NF-kappaB activation in A2058 melanoma cells: an ATM-PKCdelta-p38 MAPK-dependent mechanism

Ravi, D.; Muniyappa, H.; Das, K. C.

Mammalian ultraviolet (UV) radiation response is a gene induction cascade activated by several transcription factors, including NF-kappaB. Although NF-kappaB is induced by UV radiation, the signal transduction mechanism remains relatively unclear. In the present study, we show that UV-induced NF-kappaB activation is mediated by the activation of Ataxia telangiecia mutated (ATM) and protein kinase C (PKC). We also show that caffeine specifically inhibits UV-mediated NF-kappaB activation, but not TNFalpha-mediated NF-kappaB activation. In addition, our study shows that ATM, but not ATM-Rad3-related (ATR) or DNA-dependent protein kinase (DNA-PK) is involved in UV-induced NF-kappaB activation. Because SB203580 (a p38 MAPK inhibitor), or Calphostin C or rottlerin (PKC inhibitors) was able to inhibit UV-mediated NF-kappaB activation, we evaluated whether caffeine could inhibit p38 MAPK or PKC activity. Caffeine or rottlerin inhibited UV-induced phosphorylation of p38 MAPK, but not anisomycin-induced phosphorylation of p38 MAPK, suggesting that p38 MAPK is downstream of PKC. Additionally, caffeine could effectively inhibit UV-induced increases in PKC activity. Taken together, our study demonstrates that caffeine is a potent inhibitor of UV-induced NF-kappaB activation. Additionally, this inhibition occurs due to the inhibitory action of caffeine on ATM and PKC, resulting in the inhibition of p38 MAPK activation.

Source : Mol Cell Biochem 2008 vol.308 (1-2), pp 193 - 200

Rare and enigmatic genera (Dunnia, Schizocolea, Colletoecema), sisters to species-rich clades: Phylogeny and aspects of conservation biology in the coffee family

Rydin, C.; Razafimandimbison, S. G.; Bremer, B.

Despite extensive efforts, parts of the phylogeny of the angiosperm family Rubiaceae has not been resolved and consequently, character evolution, ancestral areas and divergence times of major radiations are difficult to estimate. Here, phylogenetic analyses of 149 taxa and five plastid gene regions show that three enigmatic genera are sisters to considerably species rich clades. The rare and endangered species Dunnia, endemic to southern Guangdong, China, is sister to a large clade in the Spermacoceae alliance; the rarely collected Schizocolea from western tropical Africa is sister to the Psychotrieae alliance; and Colletoecema from central tropical Africa is sister to remaining Rubioideae. The morphology of these taxa has been considered "puzzling". In combination with further morphological studies, our results may help understanding the apparently confusing traits of these plants. Phylogenetic, morphological, and geographical isolation of Dunnia, Schizocolea and Colletocema may indicate high genetic diversity. They are lone representatives of unique lineages and if extinct, the loss would not only mean loss of genetic diversity of a single species but of an entire lineage.

Source : Mol Phylogenet Evol 2008 vol.48 (1), pp 74 - 83

BIOCHEMISTRY / BIOTECHNOLOGY

Possible Role of Light and Polyamines in the Onset of Somatic Embryogenesis of Coffea canephora

De la Pena, C.; Galaz-Avalos, R. M.; Loyola-Vargas, V. M.

The concentration of free and bound polyamines was studied during the somatic embryogenesis induction process in Coffea canephora explants. In the present study we show that when the induction of somatic embryogenesis in C. canephora is carried out under light conditions and in the presence of the plant growth regulator, benzylaminopurine, a cytokinin, a faster response to induction is obtained. In the darkness, the response is delayed for more than 20 days, and the number of embryos is smaller. In the absence of benzylaminopurine no embryogenic response was observed. The pronounced changes in the levels of putrescine, spermidine, and spermine, both free and bound, found in C. canephora suggest that a close correlation exists between polyamine biosynthesis and somatic embryogenesis in C. canephora during a period of cellular differentiation associated with the induction of somatic embryogenesis.

Source : Mol Biotechnol 2008 vol.39 (3), pp 215 - 224

In vitro prooxidant effect of caffeine

Gulcin, I.

Caffeine is a methylxanthine compound that acts as a stimulant in humans. It is the most widely consumed behaviourally active substance in the western world and it affects calcium influx and release in living cells. Caffeine is present in various substances such as tea, coffee and some medications. This article is focused on the impact of caffeine on oxidation. Caffeine promoted the peroxidation of linoleic acid emulsions used by 32.5, 48.9, and 54.3%, respectively, at 15, 30 and 45 microg/mL concentrations. Standard antioxidants such as alpha-tocopherol and trolox, a water-soluble analogue of tocopherol, inhibited 76.2 and 93.2% peroxidation of linoleic acid emulsion at 45 microg/mL concentration. Also, PC(50) value (caffeine concentration that produced a 50% increase in linoleic acid peroxidation) of caffeine was found to be 185 microM.

Source : J Enzyme Inhib Med Chem 2008 vol.23 (1), pp 149 - 152

Dimerization of N-methyltransferases involved in caffeine biosynthesis

Kodama, Y.; Shinya, T.; Sano, H.

Caffeine is synthesized from the precursor xanthosine through three methylation and one nucleoside removal steps. Methylation is catalyzed by N-methyltransferases, designated as CaXMT1, CaMXMT1 and CaDXMT1, which, respectively, convert xanthosine into 7-methylxanthosine, 7-methylxanthine into 3,7-dimethylxanthine, and 3,7-dimethylxanthine into 1,3,7-trimethylxanthine (caffeine). In the present study, we examined their cytological and biochemical properties using fusion proteins with fluorescent proteins. All three enzymes were found to localize in cytosol as visualized by green fluorescence protein fusions. The possibility of dimer formation among these enzyme proteins was examined in vivo by transient expression of bimolecular fluorescence complementation of yellow fluorescent protein (YFP) using onion epidermal cell layers. Results showed that each enzyme protein formed a homo-dimer in cytosol as seen by a clear reconstituted YFP fluorescence. In addition, each enzyme also formed a hetero-dimer with each of the other two enzymes in cytosol. The biological significance of dimerization among structurally resembling methyltransferases involved in caffeine biosynthesis is discussed.

Source : Biochimie 2008 vol.90 (3), pp 547 - 551

Differential regulation of grain sucrose accumulation and metabolism in Coffea arabica (Arabica) and Coffea canephora (Robusta) revealed through gene expression and enzyme activity analysis

Privat, I.; Foucrier, S.; Prins, A.; Epalle, T.; Eychenne, M.; Kandalaft, L.; Caillet, V.; Lin, C.; Tanksley, S.; Foyer, C.; McCarthy, J.

* Coffea arabica (Arabica) and Coffea canephora (Robusta) are the two main cultivated species used for coffee bean production. Arabica genotypes generally produce a higher coffee quality than Robusta genotypes. Understanding the genetic basis for sucrose accumulation during coffee grain maturation is an important goal because sucrose is an important coffee flavor precursor. * Nine new Coffea genes encoding sucrose metabolism enzymes have been identified: sucrose phosphate synthase (CcSPS1, CcSPS2), sucrose phosphate phosphatase (CcSP1), cytoplasmic (CaInv3) and cell wall (CcInv4) invertases and four invertase inhibitors (CcInvI1, 2, 3, 4). * Activities and mRNA abundance of the sucrose metabolism enzymes were compared at different developmental stages in Arabica and Robusta grains, characterized by different sucrose contents in mature grain. * It is concluded that Robusta accumulates less sucrose than Arabica for two reasons: Robusta has higher sucrose synthase and acid invertase activities early in grain development - the expression of CcSS1 and CcInv2 appears to be crucial at this stage and Robusta has a lower SPS activity and low CcSPS1 expression at the final stages of grain development and hence has less capacity for sucrose re-synthesis. Regulation of vacuolar invertase CcInv2 activity by invertase inhibitors CcInvI2 and/or CcInvI3 during Arabica grain development is considered.

Source : New Phytol 2008 vol.178 (4), pp 781 - 797

New source of alpha-D-galactosidase: Germinating coffee

Wangyang, Shen; Zhengyu, Jin; Xueming, Xu; Jianwei, Zhao; Li, Deng; Hanqing, Chen; Chao, Yuan;
Dandan, Li; Xuehong, Li

Enzyme activities of alpha-Gal from dormant and germinating coffee beans (Coffea arabica) were studied and compared to develop one new source of alpha-D-galactosidase (alpha-Gal). During the germination, enzyme activity showed a continuous improvement: it increased slowly within 25 days and then rapidly increased. At the beginning of the germination, enzyme activity was lower than that from dormant coffee beans (DCB). It became higher than the latter around the 30th day, and rose to a maximum at the 35th day. The partially purified enzymes from germinating coffee beans (GCB) and DCB were obtained through ammonium sulphate precipitation, acetone precipitation and DEAE Sepharose ion exchange chromatography. The results showed that enzyme activity of purified alpha-Gal from GCB was 1.73 times greater than that from DCB. It was most stable for six weeks at its optimal pH (4.8) during the storage. GCB could become a new source of alpha-Gal instead of DCB.

Source : Food Chemistry 2008 vol.110 (4), pp 962 - 966

R-Coffee: a method for multiple alignment of non-coding RNA

Wilm, A.; Higgins, D. G.; Notredame, C.

R-Coffee is a multiple RNA alignment package, derived from T-Coffee, designed to align RNA sequences while exploiting secondary structure information. R-Coffee uses an alignment-scoring scheme that incorporates secondary structure information within the alignment. It works particularly well as an alignment improver and can be combined with any existing sequence alignment method. In this work, we used R-Coffee to compute multiple sequence alignments combining the pairwise output of sequence aligners and structural aligners. We show that R-Coffee can improve the accuracy of all the sequence aligners. We also show that the consistency-based component of T-Coffee can improve the accuracy of several structural aligners. R-Coffee was tested on 388 BRAliBase reference datasets and on 11 longer Cmfinder datasets. Altogether our results suggest that the best protocol for aligning short sequences (less than 200 nt) is the combination of R-Coffee with the RNA pairwise structural aligner Consan. We also show that the simultaneous combination of the four best sequence alignment programs with R-Coffee produces alignments almost as accurate as those obtained with R-Coffee/Consan. Finally, we show that R-Coffee can also be used to align longer datasets beyond the usual scope of structural aligners. R-Coffee is freely available for download, along with documentation, from the T-Coffee web site (http://www.tcoffee.org

Source : Nucleic Acids Res 2008 vol.36 (9), pp e52

MICROBIOLOGY

Genetic structure and biology of Xylella fastidiosa strains causing disease in citrus and coffee in Brazil

Almeida, R. P.; Nascimento, F. E.; Chau, J.; Prado, S. S.; Tsai, C. W.; Lopes, S. A.; Lopes, J. R.

Xylella fastidiosa is a vector-borne, plant-pathogenic bacterium that causes disease in citrus (citrus variegated chlorosis [CVC]) and coffee (coffee leaf scorch [CLS]) plants in Brazil. CVC and CLS occur sympatrically and share leafhopper vectors; thus, determining whether X. fastidiosa isolates can bedispersed from one crop to another and cause disease is of epidemiological importance. We sought to clarify the genetic and biological relationships between CVC- and CLS-causing X. fastidiosa isolates. We used cross-inoculation bioassays and microsatellite and multilocus sequence typing (MLST) approaches to determine the host range and genetic structure of 26 CVC and 20 CLS isolates collected from different regions in Brazil. Our results show that citrus and coffee X. fastidiosa isolates are biologically distinct. Cross-inoculation tests showed that isolates causing CVC and CLS in the field were able to colonize citrus and coffee plants, respectively, but not the other host, indicating biological isolation between the strains. The microsatellite analysis separated most X. fastidiosa populations tested on the basis of the host plant from which they were isolated. However, recombination among isolates was detected and a lack of congruency among phylogenetic trees was observed for the loci used in the MLST scheme. Altogether, our study indicates that CVC and CLS are caused by two biologically distinct strains of X. fastidiosa that have diverged but are genetically homogenized by frequent recombination.

Source : Appl Environ Microbiol 2008 vol.74 (12), pp 3690 - 3701

In vitro evaluation of the effect of nicotine, cotinine, and caffeine on oral microorganisms

Cogo, K.; Montan, M. F.; Bergamaschi, Cde C.; Andrade, E.; Rosalen, P. L.; Groppo, F. C.

The aim of this in vitro study was to evaluate the effects of nicotine, cotinine, and caffeine on the viability of some oral bacterial species. It also evaluated the ability of these bacteria to metabolize those substances. Single-species biofilms of Streptococcus gordonii, Porphyromonas gingivalis, or Fusobacterium nucleatum and dual-species biofilms of S. gordonii - F. nucleatum and F. nucleatum - P. gingivalis were grown on hydroxyapatite discs. Seven species were studied as planktonic cells, including Streptococcus oralis, Streptococcus mitis, Propionibacterium acnes, Actinomyces naeslundii, and the species mentioned above. The viability of planktonic cells and biofilms was analyzed by susceptibility tests and time-kill assays, respectively, against different concentrations of nicotine, cotinine, and caffeine. High-performance liquid chromatography was performed to quantify nicotine, cotinine, and caffeine concentrations in the culture media after the assays. Susceptibility tests and viability assays showed that nicotine, cotinine, and caffeine cannot reduce or stimulate bacterial growth. High-performance liquid chromatography results showed that nicotine, cotinine, and caffeine concentrations were not altered after bacteria exposure. These findings indicate that nicotine, cotinine, and caffeine, in the concentrations used, cannot affect significantly the growth of these oral bacterial strains. Moreover, these species do not seem to metabolize these substances.

Source : Can J Microbiol 2008 vol.54 (6), pp 501 - 508

Antiviral activities of coffee extracts in vitro

Utsunomiya, H.; Ichinose, M.; Uozaki, M.; Tsujimoto, K.; Yamasaki, H.; Koyama, A. H.

Both hot water extracts of coffee grinds and instant coffee solutions inhibited the multiplication of herpes simplex virus type 1, a representative enveloped DNA virus, when they were added to the culture medium of the virus-infected cells at a dose of one fifth the concentration suitable for drinking. The antiherpetic activity was independent of the suppliers (companies) of the coffee grinds and of the locations where the coffee beans were produced. Further characterization revealed that there are two different mechanisms, by which the coffee extracts exert inhibitory activities on the virus infection; (1) a direct inactivation of the infectivity of virus particle (i.e., a virucidal activity) and (2) the inhibition of progeny infectious virus formation at the late stage of viral multiplication in the infected cells. Caffeine, but not quinic acid and chlorogenic acid, inhibited the virus multiplication to some extent, but none of them showed the virucidal activity, suggesting that other component(s) in the coffee extracts must play a role in the observed antiviral activity. In addition, the coffee extracts inhibited the multiplication of poliovirus, a non-enveloped RNA virus, but showed no virucidal effect on this virus.

Source : Food Chem Toxicol 2008 vol.46 (6), pp 1919 - 1924

PROCESSING

Moisture measurement important throughout the value chain

Anon

Water content is an important parameter at every stage of coffee processing, being used to determine the best time for harvesting, optimise drying times, set prices for green coffee beans, and optimise roasting and grinding conditions. This paper describes some of the techniques and equipment used for determining the water content of coffee, including capacitance analysers, near-infrared (NIR) spectrophotometers, and halogen-lamp moisture analysers.

Source : Coffee Cocoa Intern 2008 (March) vol. 35 (1), pp (not vailable on line)

Ultrastructural analysis of drying damage in parchment Arabica coffee endosperm cells

Borem, F. M.; Marques, E. R.; Alves, E.

Effects of temp. (40, 50, 60°C) on the structure of parchment Arabica coffee endosperm cells during drying (airflow = 0.33 m3 s-1 m-2) were determined. Drying coffee beans at 60°C resulted in coalescence and rupture of vesicles and membranes, causing occlusion of intercellular spaces. Drying at 50°C caused disorganization in the membrane system followed by quality loss. At 40°C, the integrity of the plasma membrane was preserved and putative oil bodies remained uniformly distributed in coffee bean cells.

Source : Biosystems Engineering 2008 vol.99 (1), pp 62 - 66

COD and BOD reduction from coffee processing wastewater using Avacado peel carbon

Devi, R.; Singh, V.; Kumar, A.

The aim of this study was the assessment of reduction of chemical oxygen demand (COD) and biological oxygen demand (BOD) of wastewater from coffee processing plant using activated carbon made up of Avacado Peels. The complete study was done in batch mode to investigate the effect of operating parameters. The results of the COD and BOD concentration reduction with avocado peel carbon (APC) and commercial activated carbon (CAC) were compared and optimum operating conditions were determined for maximum reduction. Adsorption isotherm was also studied besides the calculation of optimum treatment parameters for maximum reduction of COD and BOD concentration from effluent of the coffee processing plant. The maximum percentage reduction of COD and BOD concentration under optimum operating conditions using APC was 98.20% and 99.18% respectively and with CAC this reduction was 99.02% and 99.35% respectively. As the adsorption capacity of APC is comparable with that of CAC for reduction of COD and BOD concentration, it could be a lucrative technique for treatment of domestic wastewater generated in decentralized sectors.

Source : Bioresour Technol 2008 vol.99 (6), pp 1853 - 1860

How does roasting process influence the retention of coffee aroma compounds by lyophilized coffee extract?

Lopez-Galilea, I.; Andriot, I.; Pena, M.-P. de; Cid, C.; Guichard, E.

The aims of this study were: to study the effects of lyophilized coffee extract on the retention of aroma compounds; and to determine whether aroma compound composition differs between lyophilized coffee extracts obtained from conventional and Torrefacto coffee brews prepared by filter coffeemaker and by espresso coffee machine. Variable amounts of lyophilized coffee extracts, relative to coffee powder, containing different percentages of high mol. wt. compounds, mainly melanoidins (value given in parentheses), were obtained: 20.9% (14.8) and 24.9% (23.3), respectively, for conventional and Torrefacto coffee brew prepared by filter coffeemaker and 18.1% (18.8) and 20.7% (57.5), respectively, for conventional and Torrefacto coffee brew prepared by espresso coffee machine. Retention of aroma compounds increased with increases in the lyophilized coffee extract concn. and varied between different aroma compounds. Retention of aroma compounds was found to be slightly different depending on the brewing procedure employed; lyophilized coffee extracts obtained with the espresso coffee machine had higher retention values that those extracted by the filter coffeemaker. Retention capacity of lyophilized coffee extracts obtained from the conventional and the Torrefacto roasted coffee did not show differences except in the case of ethyl nonanoate.

Source : J Food Sci 2008 vol.73 (3), pp S165 - S171

Design and implementation of an integrated management system for ochratoxin A in the coffee production chain

Lopez, Garcia R.; Mallmann, C. A.; Pineiro, M.

Mycotoxins such as ochratoxin A are known to survive the coffee roasting process and remain as a potential hazard. In Ecuador, an important coffee exporter, regulatory limits for ochratoxin A have been implemented. The potential for mycotoxin contamination is influenced by different environmental conditions and differences in harvesting, storage, processing and commercialisation. The main factors contributing to mycotoxin contamination in Ecuador coffee production are considered to be lack of selection during harvesting, delayed drying or rewetting, lack of proper drying and storage conditions, mixing of products with different moisture levels, and potential for cross contamination. An integrated mycotoxin management system using HACCP principles has been developed to prevent mycotoxin contamination at each stage of coffee production. Different demonstrative models specific for each production regions at all production levels have been developed to show the application of prevention mechanisms using limited resources and demonstrate the increased commercial value of coffee produced using good practices throughout the chain.

Source : Food Addit Contam 2008 vol.25 (2), pp 231-240

Influence of preparation conditions in the textural and chemical properties of activated carbons from a novel biomass precursor: The coffee endocarp

Nabais, J. V.; Carrott, P.; Ribeiro-Carrott, M. M.; Luz, V.; Ortiz, A. L.

In this work a novel biomass precursor for the production of activated carbons (AC) was studied. The lignocellulosic material used as precursor is the coffee bean endocarp, which constitutes an industrial residue from the Portuguese coffee industry. Activation by carbon dioxide and potassium hydroxide produces activated carbons with small external areas and pore volumes up to 0.22 and 0.43cm(3)g(-1), respectively, for CO(2) and KOH activation. All the AC's produced are very basic in nature with point of zero charge higher than 8. SEM/EDX studies indicate the presence of K, O, Ca and Si. By FTIR it was possible to identify the formation on the AC's surface of several functional groups, namely phenol, alcohol, quinone, lactone, pyrone and ether as well as SiH groups. The tailoring of the porous and chemical structure of the activated carbons produced is possible by selecting the appropriate production conditions.

Source : Bioresour Technol. 2008 vol.99 (15), pp 7224 - 7231

Evaluation of untreated coffee husks as potential biosorbents for treatment of dye contaminated waters

Oliveira, L. S.; Franca, A. S.; Alves, T. M.; Rocha, S. D.

The objective of this work was to propose an alternative use for coffee husks (CH), a coffee processing residue, as untreated sorbents for the removal of methylene blue (MB) from aqueous solutions. The effects of solution temperature, pH, biosorbent dosage and contact time on MB removal were investigated. The experimental adsorption equilibrium data were fitted to both Langmuir and Freundlich adsorption models. The biosorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, with the second-order model providing the best description of MB adsorption onto coffee husks. pH variations did not present a significant effect on MB removal. Evaluation of thermodynamics parameters indicated that the adsorption is spontaneous and endothermic. The experimental data obtained in the present study demonstrated coffee husks to be suitable candidates for use as biosorbents in the removal of cationic dyes.

Source : J Hazard Mater 2008 vol.155 (3), pp 507 - 512

Coffee oil as a potential feedstock for biodiesel production

Oliveira, L. S.; Franca, A. S.; Camargos, R. R.; Ferraz, V. P.

A preliminary evaluation of the feasibility of producing biodiesel using oil extracted from defective coffee beans was conducted as an alternative means of utilizing these beans instead of roasting for consumption of beverage with depreciated quality. Direct transesterifications of triglycerides from refined soybean oil (reference) and from oils extracted from healthy and defective coffee beans were performed. Type of alcohol employed and time were the reaction parameters studied. Sodium methoxide was used as alkaline catalyst. There was optimal phase separation after reactions using both soybean and healthy coffee beans oils when methanol was used. This was not observed when using the oil from defective beans which required further processing to obtain purified alkyl esters. Nevertheless, coffee oil was demonstrated to be a potential feedstock for biodiesel production, both from healthy and defective beans, since the corresponding oils were successfully converted to fatty acid methyl and ethyl esters.

Source : Bioresour Technol 2008 vol.99 (8), pp 3244 - 3250

Untreated coffee husks as biosorbents for the removal of heavy metals from aqueous solutions

Oliveira, W. E.; Franca, A. S.; Oliveira, L. S.; Rocha, S. D.

The objective of this work was to propose an alternative use for coffee husks (CH), a coffee processing residue, as untreated sorbents for the removal of heavy metal ions from aqueous solutions. Biosorption studies were conducted in a batch system as a function of contact time, initial metal ion concentration, biosorbent concentration and pH of the solution. A contact time of 72 h assured attainment of equilibrium for Cu(II), Cd(II) and Zn(II). The sorption efficiency after equilibrium was higher for Cu(II) (89-98% adsorption), followed by Cd(II) (65-85%) and Zn(II) (48-79%). Even though equilibrium was not attained in the case of Cr(VI) ions, sorption efficiency ranged from 79 to 86%. Sorption performance improved as metal ions concentrations were lowered. The experimental sorption equilibrium data were fitted by both Langmuir and Freundlich sorption models, with Langmuir providing the best fit (R2>0.95). The biosorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, being better described by the pseudo-second-order model (R2>0.99). The amount of metal ions sorbed increased with the biosorbent concentration in the case of Cu(II) and Cr(VI) and did not present significant variations for the other metal ions. The effect of the initial pH in the biosorption efficiency was verified in the pH range of 4-7, and the results showed that the highest adsorption capacity occurred at distinct pH values for each metal ion. A comparison of the maximum sorption capacity of several untreated biomaterial-based residues showed that coffee husks are suitable candidates for use as biosorbents in the removal of heavy metals from aqueous solutions.

Source : J Hazard Mater 2008 vol.152 (3), pp 1073 - 1081

Equilibrium data for the extraction of coffee and sunflower oils with ethanol

Pereira-Freitas, S.; Araujo-Lago, R. C.

The extraction of vegetable oils using ethanol may be a good solution for countries where small oil mills are economically feasible. Furthermore, ethanol is environmentally more attractive than the conventionally-used solvent hexane. Experimental solid-liquid equilibrium data for vegetable oil extraction with ethanol were investigated as a function of the oil content in the raw material and the sample to ethanol mass ratio. The max. solute concn. obtained in the micelle were 11.4 and 18.6%, respectively, for coffee oil prepared from green coffee beans (Robusta) and sunflower oil. These results are inferior to the typical values of between 20 and 30% obtained with countercurrent flow processes used in the food industry, using hexane as the solvent. To estimate the theoretical stages, the tie lines can be ascertained using distribution curves and solubility diagrams simultaneously.

Source : Brazil J Food Technol 2007 vol.10 (3), pp 220 - 224 (full text)

CHEMISTRY / SENSORICS

Fate of 14C-acrylamide in roasted and ground coffee during storage

Baum, M.; Bohm, N.; Gorlitz, J.; Lantz, I.; Merz, K. H.; Ternite, R.; Eisenbrand, G.

Fate of acrylamide (AA) in stored ground roasted coffee was studied for coffee samples spiked with [2,3-14C]-acrylamide (14C-AA) and stored at room temp. or 37°C for <less than or equal to>48 wk. Total radiolabel, 14C-AA contents and potential formation of 14C-AA-derived reaction products were investigated after various storage intervals for brewed coffee, filter residue and volatiles. Total 14C label decreased during coffee storage, with free 14C-AA the only 14C-associated water-extractable compound detected by radio-HPLC in brewed samples. No accumulation of other low-mol.-wt. water soluble compounds was detected and radiolabel accumulated in filter residue concomintantly with decrease of AA in coffee brew. No evidence of formation of volatile AA reaction products was observed during coffee storage or brewing and binding of radiolabel to constituents of filter residue remained largely resistant to sequential polyenzymic digestion or solvent extraction. No formation of AA furfurylthiol adducts from furanthiols (roasted coffee aroma compounds) was noted.

Source : Molecul Nutr Food Res 2008 vol.52 (5), pp 600 - 608

Modeling the formation of some polycyclic aromatic hydrocarbons during the roasting of Arabica coffee samples

Houessou, J. K.; Goujot, D.; Heyd, B.; Camel, V.

Roasting is a critical process in coffee production, as it enables the development of flavor and aroma. At the same time, roasting may lead to the formation of nondesirable compounds, such as polycyclic aromatic hydrocarbons (PAHs). In this study, Arabica green coffee beans from Cuba were roasted under controlled conditions to monitor PAH formation during the roasting process. Roasting was performed in a pilot-spouted bed roaster, with the inlet air temperature varying from 180 to 260 degrees C, for roasting conditions ranging from 5 to 20 min. Several PAHs were determined in both roasted coffee samples and green coffee samples. Different models were tested, with more or less assumptions on the chemical phenomena, with a view to predict the system global behavior. Two kinds of models were used and compared: kinetic models (based on Arrhenius law) and statistical models (neural networks). The numbers of parameters to adjust differed for the tested models, varying from three to nine for the kinetic models and from five to 13 for the neural networks. Interesting results are presented, with satisfactory correlations between experimental and predicted concentrations for some PAHs, such as pyrene, benz[a]anthracene, chrysene, and anthracene.

Source : J Agric Food Chem 2008 vol.56 (10), pp 3648 - 3656

Electron Spin Resonance (ESR) Studies on the Formation of Roasting-Induced Antioxidative Structures in Coffee Brews at Different Degrees of Roast

Bekedam, E. K.; Schols, H. A.; Cammerer, B.; Kroh, L. W.; van Boekel, M. A.; Smit, G.

The antioxidative properties of coffee brew fractions were studied using electron spin resonance spectroscopy using 2,2,6,6-tetramethyl-1-piperidin-1-oxyl (TEMPO) and Fremy's salt (nitrosodisulfonate) as stabilized radicals. TEMPO was scavenged by antioxidants formed during roasting and not by chlorogenic acid, whereas Fremy's salt was scavenged by all antioxidants tested including chlorogenic acid. The stabilized radical TEMPO allowed the exclusive measurement of roasting-induced antioxidants. The roasting-induced antioxidant activity of coffee brews increased with increasing degree of roast, and most of these antioxidants were formed during the initial roasting stage. The majority of these roasting induced antioxidants were present in the high molecular weight fractions, indicating that the formation of these antioxidants preferably occurs at specific high molecular weight structures, likely being arabinogalactan and/or protein moieties which might be part of the melanoidin complex. It was found that chlorogenic acids most probably do not lose their antioxidant activity and phenolic characteristics upon incorporation in coffee melanoidins. The parameter fast reacting antioxidants (FRA) was introduced as an alternative for the antioxidative potential. FRA levels showed that coffee fractions rich in roasting-induced antioxidants exposed their antioxidant activity relatively slowly, which must be a consequence of its complex structure. Finally, the melanoidin content and the roasting-induced antioxidant activity showed a positive and linear correlation for the coffee brew fractions, showing that roasting-induced antioxidants are present within melanoidins. This is the first time that the formation of roasting-induced antioxidants could be directly correlated with the extent of Maillard reaction and melanoidin formation in a complex product such as coffee.

Source : J Agric Food Chem 2008 vol.56 (12), pp 4597 - 4604

Comparison of the effectiveness of fatty acids, chlorogenic acids, and elements for the chemometric discrimination of coffee (Coffea arabica L.) varieties and growing origins

Bertrand, B.; Villarreal, D.; Laffargue, A.; Posada, H.; Lashermes, P.; Dussert, S.

The objective of this work was to compare the effectiveness of 3 chemical families, namely, chlorogenic acids, fatty acids, and elements, for the discrimination of Arabica varieties (traditional versus modern introgressed lines) and potential terroirs within a given coffee-growing area. The experimental design included 3 Colombian locations in full combination with 5 (1 traditional and 4 introgressed) Arabica varieties and 2 field replications. Chlorogenic acids, fatty acids, and elements were analysed in coffee bean samples by HPLC, GC, and ICP-AES, respectively. Principal component analysis and discriminant analysis were carried out to compare the 3 methods. Although elements provided an excellent classification of the 3 locations studied, this chemical class was useless for Arabica variety discrimination. Chlorogenic acids gave satisfactory results, but fatty acids clearly offered the best results for the determination of both varieties and environments, with very high percentages of correct classification (79 and 90%, respectively).

Source : J Agric Food Chem 2008 vol.56 (6), pp 2273 - 2280

Sediments in coffee extracts: Composition and control by enzymatic hydrolysis

Delgado, P. A.; Vignoli, J. A.; Siika-aho, M.; Franco, T. T.

The water-insolubility of some coffee extract components is one of the major limitations in the production of instant coffee. In this work, fractions from coffee extracts and sediments were prepared, and their chemical composition determined. Based on the carbohydrate analysis, galactomannan was found to be the main polysaccharide component of the insoluble fractions and probably responsible for sediment formation. The suitability of twelve commercial enzymes for the hydrolysis of the insoluble fractions was investigated. Pectinase 444L was the most effective enzyme in releasing sugars, mainly mannose and galactose, from these substrates. Biopectinase CCM, Rohapect B1L, Pectinase 444L and Galactomannanase ACH were found to be the most effective enzymes for reducing the sediment of coffee extracts. The highest sediment reduction was obtained using Rohapect B1L and Galactomannanase ACH, at enzyme concentrations of 0.3 and 0.1 mg protein/g substrate, respectively.

Source : Food Chem 2008 vol.110 (1), pp 168 - 176

Evaluation of moisture testing instrument of coffee

Gopinandhan, T. N.; Pannerselvam, P.; Velmourougane, K.; Raghuramulu, Y.; Jayarama

Due to the high cost of moisture meters suitable for use with coffee, coffee planters generally use traditional methods of moisture determination which results in deterioration of coffee quality at the estate level. A relatively low cost multi-channel portable moisture meter (model QCS-3Z, produced by Jranhua Electronic Instruments Co. Ltd., China), originally intended for determination of the moisture content of grains (including rice, wheat, rapeseed and other pellet grains) was evaluated for its suitability for use with coffee bean samples. Moisture contents of coffee samples were evaluated using the QCS-3Z meter, a Sinar moisture analyzer and the oven drying method set out in ISO 6673. The QCS-3Z meter was found to be user friendly and to give comparable results to the other methods in terms of accuracy and repeatability.

Source : Indian Food Industry 2008 vol.27 (1), pp 60 - 63

Development of a method for the determination of caffeine anhydrate in various designed intact tables by near-infrared spectroscopy: A comparison between reflectance and transmittance technique

Ito, M.; Suzuki, T.; Yada, S.; Kusai, A.; Nakagami, H.; Yonemochi, E.; Terada, K.

Using near-infrared (NIR) spectroscopy, an assay method which is not affected by such elements of tablet design as thickness, shape, embossing and scored line was developed. Tablets containing caffeine anhydrate were prepared by direct compression at various compression force levels using different shaped punches. NIR spectra were obtained from these intact tablets using the reflectance and transmittance techniques. A reference assay was performed by high-performance liquid chromatography (HPLC). Calibration models were generated by the partial least-squares (PLS) regression. Changes in the tablet thickness, shape, embossing and scored line caused NIR spectral changes in different ways, depending on the technique used. As a result, noticeable errors in drug content prediction occurred using calibration models generated according to the conventional method. On the other hand, when the various tablet design elements which caused the NIR spectral changes were included in the model, the prediction of the drug content in the tablets was scarcely affected by those elements when using either of the techniques. A comparison of these techniques resulted in higher predictability under the tablet design variations using the transmittance technique with preferable linearity and accuracy. This is probably attributed to the transmittance spectra which sensitively reflect the differences in tablet thickness or shape as a result of obtaining information inside the tablets.

Source : J Pharm Biomed Anal 2008 vol.47 (4-5), pp 819 - 827

A caffeine-sensitive membrane electrode: previous misleading report and present approach

Katsu, T.; Tsunamoto, Y.; Hanioka, N.; Komagoe, K.; Masuda, K.; Narimatsu, S.

Although a previous study [S.S.M. Hassan, M.A. Ahmed, M.M. Saoudi, Anal. Chem. 57 (1985) 1126] had shown that a caffeine-sensitive electrode made with picrylsulfonate and 1-octanol as a cation-exchanger and a solvent mediator, respectively, had a wide working pH range (5.5-9.5) and exhibited a Nernstian response, we could not find such response in this electrode. The present result was reasonable, because the pK(a) value of caffeinium ion was reported to be around 0.7 and the neutral form of caffeine was predominant in the pH range examined. Thus, we reinvestigated the response characteristics of a caffeine electrode, taking into consideration the pK(a) value, and constructed a new electrode with a combination of the lipophilic cation-exchanger, tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate (HFPB), and the solvent mediator with high degree of dielectric constant, 2-fluoro-2'-nitrodiphenyl ether (FNDPE). This electrode showed a pH-dependent response to caffeinium ion and gave a detection limit of 50muM with a slope of 55mV per concentration decade at pH 2. The use of other solvent mediators was less effective than that of FNDPE. The electrode was applied for the determination of caffeine in some central stimulants.

Source : Anal Chim Acta 2008 vol.620 (1-2), pp 50 - 54

Modification of the bitterness of caffeine

Keast, R.-S. J.

Caffeine is the worlds most consumed psychoactive chemical and as such is a valuable commodity to the food and beverage industry. Caffeine also activates the bitter taste system causing a potential problem for manufacturers wanting to develop products containing caffeine. In the present study both oral peripheral and central cognitive strategies were used in an attempt to suppress the bitterness of caffeine. Subjects (n=33) assessed the influence of sodium gluconate (100mM), zinc lactate (5mM), sucrose (125mM and 250mM), milk (0%, 2% and 4% milk fat), and aromas (coffee, chocolate, mocha) on the bitterness of caffeine (1.5, 3 and 4.5mM). The oral peripheral strategies proved most effective at suppressing the bitterness of caffeine: zinc lactate (-71%, p<0.05), non-fat milk (-49%, p<0.05), and sodium gluconate (-31%). Central cognitive strategies were partially effective: 250mM sucrose (-47%, p<0.05) and mocha aroma (-10%) decreased bitterness, while chocolate (+32%) and coffee (+17%) aromas increased perceived bitterness. Overall, zinc lactate was the most effective bitterness inhibitor, however the utility of zinc in foods is negated by its ability to inhibit sweetness.

Source : Food Quality and Preference 2008 vol.19 (5), pp465 - 472

Molecular beam resonant two-photon ionization study of caffeine and its hydrated clusters

Kim, D.; Kim, H. M.; Yang, K. Y.; Kim, S. K.; Kim, N. J.

We investigated electronically excited states of caffeine and its 1:1 complex with water by using resonant two-photon ionization (R2PI) and UV-UV hole-burning techniques. Strong vibronic coupling between a pair of close-lying pi-pi* and n-pi* transitions is proposed to be responsible for the broad spectral feature observed. By comparing the experimental results with those of theoretical calculations, both the O-bonded and N-bonded forms were suggested to be initially produced for the 1:1 complex. The electronic transitions of the O-bonded complex were blueshifted in the R2PI spectrum. For the N-bonded complex, the excited state undergoes an ultrafast decay process, followed by dissociation on a repulsive potential energy surface, which gives rise to a characteristically anomalous cluster distribution in nanosecond experiments.

Source : J Chem Phys 2008 vol.128 (13), pp 134310

Incorporation of chlorogenic acids in coffee brew melanoidins

Koen-Bekedam, E.; Schols, H. A.; Boekel, M.-A. J. S.; Smit, G.

The incorporation of chlorogenic acids (CGA) and their subunits quinic and caffeic acids (QA and CA) in coffee brew melanoidins was studied. Fractions with different mol. wt., ionic charges and ethanol solubilities were isolated from coffee brew. Fractions were saponified and the released QA and CA were quantified. For all melanoidin fractions, more QA than CA was released. QA levels correlated with melanoidin levels, indicating that QA was incorporated in melanoidins. QA level was correlated with increasing ionic charge of the melanoidin populations, suggesting that QA may contribute to the negative charge and consequently is, most likely, not linked via its carboxyl group. The QA level correlated with the phenolic acid group level, as determined by Folin-Ciocalteu, indicating that QA was incorporated to a similar extent as the polyphenolic moiety from CGA. QA and CA released from brew fractions by enzymes confirmed the incorporation of intact CGA. Intact CGA were proposed to be incorporated in melanoidins upon roasting via CA through mainly nonester linkages. This complex could be written as Mel=CA-QA, in which Mel represents the melanoidin backbone, =CA represents CA nonester-linked to the melanoidin backbone and -QA represents QA ester-linked to CA. Additionally, a total of 12% of QA was identified in coffee brew, whereas approx. 6% has been reported in the literature so far. The relevance of the additional QA on coffee brew stability is discussed.

Source : J Agric Food Chem 2008 vol.56 (6), pp 2055 - 2063

When machine tastes coffee: instrumental approach to predict the sensory profile of espresso coffee

Lindinger, C.; Labbe, D.; Pollien, P.; Rytz, A.; Juillerat, M. A.; Yeretzian, C.; Blank, I.

A robust and reproducible model was developed to predict the sensory profile of espresso coffee from instrumental headspace data. The model is derived from 11 different espresso coffees and validated using 8 additional espressos. The input of the model consists of (i) sensory profiles from a trained panel and (ii) on-line proton-transfer reaction mass spectrometry (PTR-MS) data. The experimental PTR-MS conditions were designed to simulate those for the sensory evaluation. Sixteen characteristic ion traces in the headspace were quantified by PTR-MS, requiring only 2 min of headspace measurement per espresso. The correlation is based on a knowledge-based standardization and normalization of both datasets that selectively extracts differences in the quality of samples, while reducing the impact of variations on the overall intensity of coffees. This work represents a significant progress in terms of correlation of sensory with instrumental results exemplified on coffee.

Source : Anal Chem 2008 vol.80 (5), pp 1574 - 1581

Application of multivariate analysis to investigate potential antioxidants in conventional and torrefacto roasted coffee

Lopez-Galilea, I.; Paz-de-Pena, M.; Cid, C.

Multivariate statistical techniques were applied to investigate potential antioxidant compounds in commercially available conventional and torrefacto roasted coffees. Statistical analyses showed significant correlations between contents of browned compounds, trigonelline, 5-caffeoylquinic acid and caffeic acid, and antioxidative activity measured by both DPPH- and redox potential methods. Trigonelline solutions showed an antioxidative activity close to zero and should not be considered as potential antioxidant compounds. Principal component analysis (PCA) was applied to evaluate the correlations between antioxidant capacity and coffee chemical compounds. Conventional and torrefacto roasted coffees were separated by PC1 (62.5% of the total variance), characterized by antioxidant capacity and chemical compounds highly correlated with antioxidant capacity. A descriptive chemical characterization of conventional and torrefacto ground roasted coffee was also performed. 69 volatile compounds were identified and quantified. Their negative correlations with antioxidant capacity suggest the occurrence of pro-oxidative activity that should be investigated further.

Source : Eur Food Res Technol 2008 vol.227 (1), pp 141 - 149

Studies on extraction and antioxidant potential of green coffee

Madhava, Naidu M.; Sulochanamma, G.; Sampathu, S. R.; Srinivas, P.

The coffee industry in India is reported to have excess supply over demand, and the development of value-added products from coffee is of interest. The antioxidant and antineoplastic properties of coffee extracts have been reported, but there is limited information on the antioxidant activity of coffee conserve from green coffee. In this study, the extraction conditions for obtaining an antioxidant-rich conserve were optimised, and the antioxidant activities of the conserves were evaluated; the chlorogenic acid of the conserves was also purified and characterised. The green coffee was found to contain polyphenols and chlorogenic acid with high antioxidant properties. Chlorogenic acid was the main compound in the purified conserve, and the potential use of conserves from green coffee as nutraceuticals and preservatives in food formulations is suggested.

Source : Food Chem 2008 vol.107 (1), pp 377-384

Determination of moisture in raw coffee by near infra-red reflectance spectroscopy and multivariate regression

Morgano, M. A.; Gomes-Faria, C.; Flores-Ferrao, M.; Bragagnolo, N.; Castro-Ferreira, M.-M. de

: NIR spectroscopy was used to measure the moisture content of raw coffee. Different models using partial least squares (PLS) with data pre-processing were employed. Regression models were constructed with 157 spectra of the samples of raw coffee collected between 4500 and 10 000 cm-1. The original NIR spectra underwent different transformations and mathematical pretreatments, such as the Kubelka-Munk transformation, multiplicative signal correction, spline smoothing and movable average, and the data were scaled by variance. The regression model permitted the determination of the moisture content of the raw coffee samples with a s.e. of calibration (SEC) = 0.569 g/100 g, s.e. of validation = 0.298 g/100 g, correlation coeff. (r) for calibration and validation of 0.712 and 0.818, respectively, and average relative error of 4.1% for validation samples.

Source : Ciencia e Tecnologia de Alimentos.2008 vol.28 (1), pp 12 - 17 (full text in Portuguese)

Rhamnoarabinosyl and rhamnoarabinoarabinosyl side chains as structural features of coffee arabinogalactans

Nunes, F. M.; Reis, A.; Silva, A.-M. S.; Domingues, M.-R. M.; Coimbra, M. A.

1H and 13C NMR was used to characterize arabinogalactans in hot water extracts of green coffee beans. Rhamnoarabinosyl and rhamnoarabinoarabinosyl side chains were identified as structural features of arabinogalactans, and are described.

Source : Phytochemistry 2008 vo/.69 (7), pp 1573 - 1585

Fast simultaneous analysis of caffeine, trigonelline, nicotinic acid and sucrose in coffee by liquid chromatography-mass spectrometry

Perrone, D.; Donangelo, C. M.; Farah, A.

A rapid liquid chromatography-mass spectrometry method for the simultaneous quantification of caffeine, trigonelline, nicotinic acid and sucrose in coffee was developed and validated. The method involved extraction with hot water, clarification with basic lead acetate and membrane filtration, followed by chromatographic separation using a Spherisorb S5 ODS2, 5mum chromatographic column and gradient elution with 0.3% aqueous formic acid/methanol at a flow rate of 0.2 ml/min. The electrospray ionization source was operated in the negative mode to generate sucrose ions and in the positive mode to generate caffeine, trigonelline and nicotinic acid ions. Ionization suppression of all analytes was found due to matrix effect. Calibrations curves prepared in green and roasted coffee extracts were linear with r2 >0.999. Roasted coffee was spiked and recoveries ranged from 93.0% to 105.1% for caffeine, from 85.2% to 116.2% for trigonelline, from 89.6% to 113.5% for nicotinic acid and from 94.1% to 109.7% for sucrose. Good repeatibilities (RSD <5%) were found for all analytes in the matrix. The limit of detection (LOD), calculated on the basis of signal-to-noise ratios of 3:1, was 11.9, 36.4, 18.5 and 5.0 ng/ml for caffeine, trigonelline, nicotinic acid and sucrose, respectively. Analysis of 11 coffee samples (regular or decaffeinated green, ground roasted and instant) gave results in agreement with the literature. The method showed to be suitable for different types of coffee available in the market thus appearing as a fast and reliable alternative method to be used for routine coffee analysis.

Source : Food Chem 2008 vol.110 (4), pp 1030 - 1035

Study on extraction efficiency of natural antioxidant in coffee by capillary electrophoresis with amperometric detection

Qingcui, Chu; Miao, Lin; Xueqin, Yu; Jiannong, Ye

Capillary electrophoresis with amperometric detection (CE-AD) was investigated for the determination of catechin, rutin, ferulic acid, o-dihydroxybenzene, chlorogenic acid, caffeic acid, gallic acid and protocatechuic acid in coffee. Comparison of the extraction efficiency of antioxidants using different polar solvents was also conducted by this method. Effects of several important factors, including the acidity and concn. of the running buffer, separation voltage and working electrode potential, were evaluated to obtain the optimum analysis conditions. The working electrode was a 300 mum carbon disc electrode at an applied potential of +0.95 V (vs. a saturated calomel reference electrode). Under optimal conditions, the analytes could be well separated within 26 min in a 75 cm length fused-silica capillary (i.d. 2.5 x 10-5 m). The current response was linear over 3 orders of magnitude with detection limits (S/N = 3) ranging from 6.0 x 10-8 to 3.6 x 10-7 g/ml for all analytes.

Source : Eur Food Res Technol 2008 vol.226 (6), pp 1373 - 1378

Headspace solid-phase microextraction-gas chromatographic-time-of-flight mass spectrometric methodology for geographical origin verification of coffee

Risticevic, S.; Carasek, E.; Pawliszyn, J.

Increasing consumer awareness of food safety issues requires the development of highly sophisticated techniques for the authentication of food commodities. The food products targeted for falsification are either products of high commercial value or those produced in large quantities. For this reason, the present investigation is directed towards the characterization of coffee samples according to the geographical origin. The conducted research involves the development of a rapid headspace solid-phase microextraction (HS-SPME)-gas chromatography-time-of-flight mass spectrometry (GC-TOFMS) method that is utilized for the verification of geographical origin traceability of coffee samples. As opposed to the utilization of traditional univariate optimization methods, the current study employs the application of multivariate experimental designs to the optimization of extraction-influencing parameters. Hence, the two-level full factorial first-order design aided in the identification of two influential variables: extraction time and sample temperature. The optimum set of conditions for the two variables was 12 min and 55 degrees C, respectively, as directed by utilization of Doehlert matrix and response surface methodology. The high-throughput automated SPME procedure was completed by implementing a single divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) 50/30 microm metal fiber with excellent durability properties ensuring the completion of overall sequence of coffee samples. The utilization of high-speed TOFMS instrument ensured the completion of one GC-MS run of a complex coffee sample in 7.9 min and the complete list of benefits provided by ChromaTOF software including fully automated background subtraction, baseline correction, peak find and mass spectral deconvolution algorithms was exploited during the data evaluation procedure. The combination of the retention index (RI) system using C(8)-C(40) alkanes and the mass spectral library search was utilized for the confirmation of analyte identity in the reference authentic Brazilian coffee sample. The semi-quantitative results were then submitted to statistical evaluation, namely principal component analysis (PCA) for the establishment of geographical origin discriminations.

Source : Anal Chim Acta 2008 vol.617 (1-2), pp 72 - 84

Reduction of nitrous acid to nitric oxide by coffee melanoidins and enhancement of the reduction by thiocyanate: possibility of its occurrence in the stomach

Takahama, U.; Hirota, S.

Reactions of nitrous acid with freeze-dried instant coffee and its methanol-insoluble melanoidin fractions were studied at pH 2 in the presence and absence of thiocyanate (SCN (-)), simulating the mixture of coffee, saliva, and gastric juice. Coffee contained stable radicals, and the radical concentration increased by ferricyanide and decreased by ascorbic acid. This result indicates that the radical concentration was affected by the redox state of coffee and that the nature of the radical was due to quinhydrone structure that might be included in coffee melanoidins. Nitrite also increased the electron spin resonance (ESR) signal intensity at pH 2, suggesting that nitrite oxidized melanoidins producing nitric oxide (NO). The formation of NO could be detected by oxygen uptake due to the autoxidation of NO and using an NO-trapping agent. SCN (-) largely enhanced NO formation in coffee and methanol-insoluble melanoidin fractions but only slightly in a methanol-soluble fraction, and the enhancement accompanied the consumption of SCN (-) but did not accompany the formation of a stable ESR signal. The enhancement was explained by the reduction of NOSCN by melanoidins in methanol-insoluble fractions and that the consumption was due to binding of SCN (-) to melanoidins during their oxidation by nitrous acid. The result obtained in this study suggests that when coffee is ingested, in addition to chlorogenic acid and its isomers, melanoidins can also react with salivary nitrite and SCN (-) in the gastric lumen, producing NO.

Source : J Agric Food Chem 2008 vol.56 (12), pp 4736 - 4744

Determination of ochratoxin A in green coffee beans by solid-phase microextraction and liquid chromatography with fluorescence detection

Vatinno, R.; Aresta, A.; Zambonin, C. G.; Palmisano, F.

Development of an LC technique for determination of ochratoxin A (OTA) in green coffee beans is described. The method is based on: extraction into 5% NaHCO3 solution; clean up by chloroform partition; acidification; solid phase microextraction; and OTA determination by LC with fluorescence detection. Detection and quantitation limits obtained for OTA (calculated at signal-to-noise ratio of 3 and 10) were 0.3 and 2 ng/g, respectively.

Source : J Chromatography A 2008 vol.1187 (1-2). pp 145 - 150

Low molecular weight melanoidins in coffee brew

Bekedam, E. K.; Roos, E.; Schols, H. A.; van Boekel, M. A.; Smit, G.

Analysis of low molecular weight (LMw) coffee brew melanoidins is challenging due to the presence of many non-melanoidin components that complicate analysis. This study focused on the isolation of LMw coffee brew melanoidins by separation of melanoidins from non-melanoidin components that are present in LMw coffee brew material. LMw coffee fractions differing in polarity were obtained by reversed-phase solid phase extraction and their melanoidin, sugar, nitrogen, caffeine, trigonelline, 5-caffeoylquinic acid, quinic acid, caffeic acid, and phenolic groups contents were determined. The sugar composition, the charge properties, and the absorbance at various wavelengths were investigated as well. The majority of the LMw melanoidins were found to have an apolar character, whereas most non-melanoidins have a polar character. The three isolated melanoidin-rich fractions represented 56% of the LMw coffee melanoidins and were free from non-melanoidin components. Spectroscopic analysis revealed that the melanoidins isolated showed similar features as high molecular weight coffee melanoidins. All three melanoidin fractions contained approximately 3% nitrogen, indicating the presence of incorporated amino acids or proteins. Surprisingly, glucose was the main sugar present in these melanoidins, and it was reasoned that sucrose is the most likely source for this glucose within the melanoidin structure. It was also found that LMw melanoidins exposed a negative charge, and this negative charge was inversely proportional to the apolar character of the melanoidins. Phenolic group levels as high as 47% were found, which could be explained by the incorporation of chlorogenic acids in these melanoidins.

Source : J.Agric Food Chem 2008 vol.56 (11), pp 4060 - 4067

COFFEE & HEALTH

Placebo response to caffeine improves reaction time performance in sleepy people

Anderson, C.; Horne, J. A.

Caffeine is the most widely used stimulant to counteract sleepiness. However, little is known about any placebo effect of caffeine in sleepy people and the effect of suggestibility. Over a 95 min test period, and in a counterbalanced design, 16 young healthy adults underwent 3 x 30 min sessions at the psychomotor vigilance test (PVT), during an early afternoon 'dip' enhanced by a prior night's sleep restriction (5 h). On both occasions they were given a cup of a decaffeinated coffee; once when the participant was verbally primed to suggest the coffee was caffeinated (Placebo) and on the other under neutral priming (Control). There were significantly fewer lapses and shorter reaction times following Placebo, for the initial two 30 min sessions, indicating that suggestion about consuming caffeine was effective in improving performance in moderately sleepy people.

Source : Hum Psychopharmacol 2008 vol.23 (4), pp 333 - 336

Coffee consumption and mortality in a 14-year follow-up of an elderly northern Finnish population

Happonen, P.; Laara, E.; Hiltunen, L.; Luukinen, H.

The relationship between coffee consumption and mortality in a home-dwelling elderly population was examined. A population-based cohort of 817 men and women born in 1920 or earlier and living in northern Finland provided complete data on daily coffee consumption and other variables at the baseline examination in 1991-1992. Deaths were monitored through to the end of 2005 by national death certificates, resulting in 6960 person-yr of follow-up. Hazard rate ratios for mortality by daily coffee intake were estimated by Poisson regression models adjusted for some known predictors of mortality. During 14.5 yr of follow-up, 623 deaths occurred. The total mortality rate was inversely related to the number of cups (average vol., 125 ml) of coffee consumed daily. After adjustment for age, sub-period of follow-up, sex, marital status, basic educational level, previous occupational group, current smoking, BMI, history of myocardial infarction, self-rated health and presence of diabetes, cognitive impairment or physical disability, the estimated relative risk reduction of total mortality per an increment of 1 more cup of coffee
per day reported at baseline was 4 (95% CI 0, 8)%. The observed associations between coffee consumption and mortality from CVD, cancer and other or unknown causes, respectively, were qualitatively similar to that of total mortality but the estimates were less precise. The effect of coffee consumption at baseline appeared to attenuate after 10 yr since the start of follow-up. This study provides evidence for daily (caffeine-containing) coffee intake being inversely associated with mortality in the elderly .

Source : J Nutrition 2008 vol.99 (6), pp 1354 - 1361

Effects of oral administration of caffeine and D-ribose on mental fatigue

Ataka, S.; Tanaka, M.; Nozaki, S.; Mizuma, H.; Mizuno, K.; Tahara, T.; Sugino, T.; Shirai, T.; Kajimoto, Y.; Kuratsune, H.; Kajimoto, O.; Watanabe, Y.

Effects of caffeine and D-ribose on mental fatigue were studied in 17 subjects (average age 36.5 yr) in a double-blind trial. Subjects consumed caffeine (200 mg/day), D-ribose (2000 mg/day) or placebo for 8 days prior to performing fatigue inducing mental tasks (advanced trail-making and Uchida-Kraepelin psychodiagnostic tests) on 4 occasions. Oral administration of caffeine improved task performance without increased sensation of fatigue, motivation or sleepiness. However, plasma levels of branched chain amino acids (a biomarker of mental fatigue) were lower in the caffeine group than the placebo group. Oral administration of D-ribose had no effect at the dosage used.

Source : Nutrition 2008 vol.24 (3), pp 233 - 238 (not available on line)

A two-gate model for the ryanodine receptor with allosteric modulation by caffeine and quercetin

Baran, I.; Ganea, C.; Baran, V.

We have developed a model of the tetrameric ryanodine receptor-the calcium channel of the sarcoplasmic reticulum. The model accurately describes published experimental data on channel activity at various concentrations of Ca(2+), caffeine and quercetin. The proposed mechanisms involve allosteric regulation of Ca(2+) affinity by both caffeine and quercetin, and the existence of two independent, A- and I-gates controlled by Ca(2+) binding to an activating and an inhibitory module of the receptor. There are four different configurations of the receptor that affect ligand binding to the activation module, but not to the inhibition module. Consequently, there are four kinetic modes for the A-gate and one mode for the I-gate. At a certain moment, the receptor can be in any of the four possible conformations with equal probability. By fitting the data we are able to derive ligand affinities and Hill coefficients, to describe the observation that quercetin is an activating agent stronger than caffeine, and that caffeine and quercetin activate the channel at very low Ca(2+) concentration ( approximately 10(-11) M). We predict that the activation regime at saturating caffeine or quercetin should present four distinct regions at increasing Ca(2+) corresponding to the four different gating modes. Another interesting prediction is the enlargement of the activity domain toward higher Ca(2+) concentrations in the presence of caffeine or quercetin.

Source : Eur Biophys J 2008 vol.37 (6), pp 793 - 806

Dose effect of caffeine on testosterone and cortisol responses to resistance exercise

Beaven, C. M.; Hopkins, W. G.; Hansen, K. T.; Wood, M. R.; Cronin, J. B.; Lowe, T. E.

Interest in the use of caffeine as an ergogenic aid has increased since the International Olympic Committee lifted the partial ban on its use. Caffeine has beneficial effects on various aspects of athletic performance, but its effects on training have been neglected. PURPOSE: To investigate the acute effect of caffeine on the exercise-associated increases in testosterone and cortisol in a double-blind crossover study. METHODS: Twenty-four professional rugby-league players ingested caffeine doses of 0,200, 400, and 800 mg in random order 1 hr before a resistance-exercise session. Saliva was sampled at the time of caffeine ingestion, at 15-min intervals throughout each session, and 15 and 30 min after the session. Data were log-transformed to estimate percent effects with mixed modeling, and effects were standardized to assess magnitudes. RESULTS: Testosterone concentration showed a small increase of 15% (90% confidence limits, +/- 19%) during exercise. Caffeine raised this concentration in a dosedependent manner by a further small 21% (+/- 24%) at the highest dose. The 800-mg dose also produced a moderate 52% (+/- 44%) increase in cortisol. The effect of caffeine on the testosterone:cortisol ratio was a small decline (14%; +/- 21%).

CONCLUSION: Caffeine has some potential to benefit training outcomes via the anabolic effects of the increase in testosterone concentration, but this benefit might be counteracted by the opposing catabolic effects of the increase in cortisol and resultant decline in the testosterone:cortisol ratio.

Source : Int J Sport Nutr Exerc Metab 2008 vol.18 (2), pp 131 - 141 (not avvailable on line)

Altered intestinal absorption of L-thyroxine caused by coffee

Benvenga, S.; Bartolone, L.; Pappalardo, M. A.; Russo, A.; Lapa, D.; Giorgianni, G.; Saraceno, G.;
Trimarchi, F.

OBJECTIVE: To report eight case histories, and in vivo and in vitro studies showing coffee's potential to impair thyroxine (T4) intestinal absorption. DESIGN: Of eight women with inappropriately high or nonsuppressed thyroid-stimulating hormone (TSH) when T4 was swallowed with coffee/espresso, six consented to the evaluation of their T4 intestinal absorption. This in vivo test was also administered to nine volunteers. In three separate tests, two 100 microg T4 tablets were swallowed with coffee, water, or water followed, 60 minutes later, by coffee. Serum T4 was assayed over the 4-hour period of the test. Two patients and two volunteers also agreed on having tested the intestinal absorption of T4 swallowed with solubilized dietary fibers. In the in vitro studies, classical recovery tests on known concentrations of T4 were performed in the presence of saline, coffee, or known T4 sequestrants (dietary fibers, aluminium hydroxide, and sucralfate). MAIN OUTCOME: For the in vivo test, average and peak incremental rise of serum T4 (AIRST4 and PIRST4), time of maximal incremental rise of serum T4 (TMIRST4), and area under the curve (AUC) were determined. In patients and volunteers, the four outcome measures were similar in the water and water + coffee tests. In patients and volunteers, compared to water, coffee lowered AIRST4 (by 36% and 29%), PIRST4 (by 30% and 19%), and AUC (by 36% and 27%) and delayed TMIRST4 (by 38 and 43 minutes); bran was a superior interferer. In the in vitro studies, coffee was weaker than known T4 sequestrants.

CONCLUSION: Coffee should be added to the list of interferers of T4 intestinal absorption, and T4 to the list of compounds whose absorption is affected by coffee.

Source : Thyroid 2008 vol.18 (3), pp 293 - 301

Altered intestinal absorption of L-thyroxine caused by coffee

Benvenga, S.; Bartolone, L.; Pappalardo, M. A.; Russo, A.; Lapa, D.; Giorgianni, G.; Saraceno, G.;
Trimarchi, F.

CONCLUSION: Coffee should be added to the list of interferers of T4 intestinal absorption, and T4 to the list of compounds whose absorption is affected by coffee.

Source : Thyroid 2008 vol.18 (3), pp 293 - 301

Percutaneous release of caffeine from microemulsion, emulsion and gel dosage forms

Bolzinger, M. A.; Briancon, S.; Pelletier, J.; Fessi, H.; Chevalier, Y.

The transport of caffeine to the hypodermis by an alcohol-free o/w microemulsion was investigated and compared with an aqueous gel and an o/w emulsion. The microemulsion was well characterized and in vitro diffusion measurements through pig skin having the hypodermis either kept or removed were performed in static Franz cells. The microemulsion allowed delivery of a large fraction of the caffeine in the hypodermis: 23% of caffeine reached the hypodermis after 24h diffusion, 1.3-fold larger than from the emulsion and gel dosage forms. Half this amount was stored in the hypodermis, the other half continuing its diffusion to the receptor compartment of the Franz cell.

Source : Eur J Pharm Biopharm 2008 vol.68 (2), pp 446 - 451

Caffeine stimulates ventilation in athletes with exercise-induced hypoxemia

Chapman, R. F.; Stager, J. M.

Many athletes with exercise-induced hypoxemia (EIH) show an insufficient ventilatory response to exercise and low resting ventilatory responsiveness. The purpose of this project was to determine whether a moderate dosage of caffeine, a common ventilatory stimulant, could augment resting ventilatory responsiveness, exercise ventilation (V E), end-tidal O2 partial pressure (PetO2), and arterial oxyhemoglobin saturation (HbSaO2) in athletes with EIH. METHODS:: Eight highly trained males (V O2max, 69.2 +/- 4.0 mL.[kg.min]) who demonstrated EIH at V O2max (HbSaO2, 88.0 +/- 1.7%), ingested in a randomized design a placebo or caffeine (CAF, 8 mg.kg body wt) 1 h before testing. Ventilatory responsiveness at rest was assessed via the isocapnic hypoxic and hyperoxic hypercapnic ventilatory responses (HVR and HCVR, respectively). Dependent measures of metabolic variables, ventilation, and saturation were determined during progressive treadmill exercise to exhaustion. RESULTS:: V E was higher at 75%, 80%, and 100% of V O2max with CAF (P < 0.05). V E/V O2, PetO2, and HbSaO2 were increased at 75%, 80%, and 90% of V O2max with CAF but were not different at V O2max despite an increase in V e. No change in V O2max was observed between treatments. HVR and HCVR were not different between the two conditions, indicating that the increased V E likely came from central stimulation or secondary effects of CAF.

CONCLUSION:: The failure of HbSaO2 to increase at V O2max despite an increase in V E suggests that mechanisms influencing HbSaO2 other than an inadequate hyperventilatory response may operate to different degrees across individuals as V O2max is approached.

Source : Med Sci Sports Exerc 2008 vol.40 (6), pp 1080 - 1086

Caffeine blocks disruption of blood brain barrier in a rabbit model of Alzheimer\'s disease

Chen, X.; Gawryluk, J. W.; Wagener, J. F.; Ghribi, O.; Geiger, J. D.

High levels of serum cholesterol and disruptions of the blood brain barrier (BBB) have all been implicated as underlying mechanisms in the pathogenesis of Alzheimer's disease. Results from studies conducted in animals and humans suggest that caffeine might be protective against Alzheimer's disease but by poorly understood mechanisms. Using rabbits fed a cholesterol-enriched diet, we tested our hypothesis that chronic ingestion of caffeine protects against high cholesterol diet-induced disruptions of the BBB. New Zealand rabbits were fed a 2% cholesterol-enriched diet, and 3 mg caffeine was administered daily in drinking water for 12 weeks. Total cholesterol and caffeine concentrations from blood were measured. Olfactory bulbs (and for some studies hippocampus and cerebral cortex as well) were evaluated for BBB leakage, BBB tight junction protein expression levels, activation of astrocytes, and microglia density using histological, immunostaining and immunoblotting techniques. We found that caffeine blocked high cholesterol diet-induced increases in extravasation of IgG and fibrinogen, increases in leakage of Evan's blue dye, decreases in levels of the tight junction proteins occludin and ZO-1, increases in astrocytes activation and microglia density where IgG extravasation was present. Chronic ingestion of caffeine protects against high cholesterol diet-induced increases in disruptions of the BBB, and caffeine and drugs similar to caffeine might be useful in the treatment of Alzheimer's disease.

Source : J.Neuroinflammation. 2008 vol.5, pp 12

Caffeine prevents age-associated recognition memory decline and changes brain-derived neurotrophic factor and tirosine kinase receptor (TrkB) content in mice

Costa, M. S.; Botton, P. H.; Mioranzza, S.; Souza, D. O.; Porciuncula, L. O.

The beneficial effects of caffeine on cognition are controversial in humans, whereas its benefit in rodents had been well characterized. However, most studies were performed with acute administration of caffeine and the tasks used to evaluate cognition had aversive components. Here, we evaluated adulthood administration of caffeine up to old age on recognition memory in mice using the object recognition task (ORT) and on brain-derived neurotrophic factor (BNDF) and tirosine kinase receptor (TrkB) immunocontent in the hippocampus. Adult mice (6 months old) received either drinking water or caffeine (1 mg/mL) during 12 months. At 18 months of age both groups were tested for ORT. Our results showed that aged mice exhibited lower performance in the recognition memory compared with adults (6 months old). Furthermore, caffeine-treated mice showed similar performance to adult mice in the ORT and an improvement compared with their age-matched control mice. Caffeine also counteracted the age-related increase in BDNF and TrkB immunocontent. Our results corroborate with other studies and reinforce that caffeine consumed in adulthood may prevent recognition memory decline with aging. This preventive effect may involve a decrease in the hippocampal BDNF and TrkB immunocontent.

Source : Neuroscience 2008 vol.153 (4), pp 1071 - 1078

Caffeine effects on short-term performance during prolonged exercise in the heat

Del Coso, J.; Estevez, E.; Mora-Rodriguez, R.

PURPOSE: To determine the effect of water, carbohydrate, and caffeine ingestion on fatigue during prolonged exercise in the heat. METHODS: Seven endurance-trained cyclists (V O2max = 61 +/- 8 mL.kg.min) pedaled for 120 min at 63% V O2max in a hot-dry environment (36 degrees C; 29% humidity), ingesting either no fluid (NF), water (WAT) to replace 97% fluid losses, the same volume of a 6% carbohydrate-electrolyte solution (CES), or each of these treatments along with ingestion of 6 mg of caffeine per kilogram of body weight (NF + CAFF, WAT + CAFF, and CES + CAFF). At regular intervals during exercise, maximal cycling power (PMAX) was measured. Before and after exercise, maximal voluntary contraction (MVC), voluntary activation (VA), and electrically evoked contractile properties of the quadriceps were determined. RESULTS: Without fluid replacement (NF and NF + CAFF), subjects were dehydrated by 3.8 +/- 0.3%, and rectal temperature reached 39.4 +/- 0.3 degrees C, while it was maintained at 38.7 +/- 0.3 degrees C in trials with rehydration (P < 0.05). Trials with caffeine ingestion increased PMAX by 3% above trials without caffeine (P < 0.05). MVC reductions after exercise were larger with NF (-11 +/- 5%) than for the rest of the trials (P < 0.05). MVC was reduced in WAT compared with CES + CAFF (-6 +/- 4 vs 2 +/- 4%; P < 0.05). However, NF + CAFF maintained MVC at the level of the CES trial. VA showed the same treatment response pattern as MVC. There were no differences in electrically evoked contractile properties among trials.

CONCLUSION: During prolonged exercise in the heat, caffeine ingestion (6 mg.kg body weight) maintains MVC and increases PMAX despite dehydration and hyperthermia. When combined with water and carbohydrate, caffeine ingestion increases maximal leg force by increasing VA (i.e., reducing central fatigue).

Source : Med.Sci.Sports Exerc. vol.40 Issue 4 pp 744 - 751

An update on the mechanisms of the psychostimulant effects of caffeine

Ferre, S.

There has been a long debate about the predominant involvement of the different adenosine receptor subtypes and the preferential role of pre- versus post-synaptic mechanisms in the psychostimulant effects of the adenosine receptor antagonist caffeine. Both striatal A(1) and A(2A) receptors are involved in the motor-activating and probably reinforcing effects of caffeine, although they play a different role under conditions of acute or chronic caffeine administration. The present review emphasizes the key integrative role of adenosine and adenosine receptor heteromers in the computation of information at the level of the striatal spine module (SSM). This local module is mostly represented by the dendritic spine of the medium spiny neuron with its glutamatergic and dopaminergic synapses and astroglial processes that wrap the glutamatergic synapse. In the SSM, adenosine acts both pre- and post-synaptically through multiple mechanisms, which depend on heteromerization of A(1) and A(2A) receptors among themselves and with D(1) and D(2) receptors, respectively. A critical aspect of the mechanisms of the psychostimulant effects of caffeine is its ability to release the pre- and post-synaptic brakes that adenosine imposes on dopaminergic neurotransmission by acting on different adenosine receptor heteromers localized in different elements of the SSM.

Source : J Neurochem 2008 vol.105 (4), pp 1067 - 1079

Effect of caffeine on leg-muscle pain during intense cycling exercise: possible role of anxiety sensitivity

Gliottoni, R. C.; Motl, R. W.

This experiment examined the effect of a moderate dose of caffeine on perceptions of leg-muscle pain during a bout of high-intensity cycling exercise and the role of anxiety sensitivity in the hypoalgesic effect of caffeine on muscle pain during exercise. Sixteen college-age women ingested caffeine (5 mg/kg body weight) or a placebo and 1 hr later completed 30 min of cycling on an ergometer at 80% of peak aerobic capacity. The conditions were completed in a counterbalanced order, and perceptions of leg-muscle pain were recorded during the bouts of exercise. Caffeine resulted in a large reduction in leg-muscle pain-intensity ratings compared with placebo (d = -0.95), and the reduction in leg-muscle pain-intensity ratings was larger in those with lower anxiety-sensitivity scores than those with higher anxiety-sensitivity scores (d = -1.28 based on a difference in difference scores). The results support that caffeine ingestion has a large effect on reducing leg-muscle pain during high-intensity exercise, and the effect is moderated by anxiety sensitivity.

Source : Int J Sport Nutr Exerc Metab 2008 vol.18 (2), pp 103 - 115

Prenatal caffeine assessment: fetal and maternal biomarkers or self-reported intake?

Grosso, L. M.; Triche, E.; Benowitz, N. L.; Bracken, M. B.

We sought to examine associations among measures of caffeine exposure, including maternal urine, umbilical cord blood, and maternal self report. METHODS: Pregnant women were recruited from 56 obstetric practices and 15 clinics associated with six hospitals in Connecticut and Massachusetts between September 1996 and January 2000; 3633 women were enrolled. Maternal urine throughout pregnancy and umbilical cord blood samples were analyzed for caffeine, paraxanthine, theophylline, and theobromine. Maternal caffeine intake was assessed throughout pregnancy. RESULTS: Urinary and cord blood biomarkers were correlated with reported intake throughout pregnancy (range r = 0.35-0.66; p < 0.0001). Infants of smokers had greater cord blood concentrations of paraxanthine, reflecting faster caffeine metabolism in smokers, and cord blood paraxanthine levels were more strongly correlated with intake in smokers. CONCLUSION: Maternal self reported intake may still be the optimal and most valid measure of antenatal caffeine exposure, since biomarkers do not reflect exposure over pregnancy.

Source : Ann Epidemiol 2008 vol.18 (3), pp 172 - 178

Lack of association of the Trp64Arg polymorphism of beta3-adrenergic receptor gene with energy

Hamada, T.; Kotani, K.; Higashi, A.; Ikeda, J.; Tagaki, E.; Igarashi, A.; Matsubara, C.; Yoshida, T.; Sakane,
N.

A close relationship between coffee intake and certain metabolic disorders is known. Caffeine, one of coffee components, can increase energy expenditure (EE), but there are considerable individual differences in the caffeine effects on EE, and the causes have not been fully established in humans. The Arg allele in the beta(3)-adrenergic receptor gene (beta(3)-AR), a marker for obesity-related traits, may be a contributor to individual variations in EE. This study investigated the effect of the Arg allele of beta(3)-AR on caffeine-induced increases in EE. In 44 healthy young women (21 +/- 1 years), physical characteristics, blood pressure, biochemical profiles and dietary nutritional intake were measured. A caffeine-loading test was conducted at a dosage of 4 mg per body weight (kg). EE was measured using an indirect open-circuit calorimeter for a 10-min period before, and at 30 min and 60 min after the caffeine-loading test. The beta(3)-AR Trp64Arg polymorphism was detected with a PCR-restriction fragment length polymorphism method. The frequency of the Arg allele was 24%. The distribution of the Trp/Trp, Trp/Arg, and Arg/Arg genotypes was 58%, 36%, and 6%, respectively. At the baseline, subjects with the Arg/Arg genotype had a significantly lower EE level than those with the Trp/Trp or Trp/Arg genotype. After the caffeine-loading test, there were caffeine-induced increases in EE in all genotypes, but there were no differences in the levels of increase among the genotypes. These findings suggest that the genotypes of beta(3)-AR Trp64Arg polymorphism might be not associated with caffeine-induced increases in EE levels.

Source : Tohoku J Exp Med 2008 vol.214 (4), pp 365 - 370

Protein phosphatase Siw14 controls intracellular localization of Gln3 in cooperation with Npr1 kinase in

Hirasaki, M.; Kaneko, Y.; Harashima, S.

Saccharomyces cerevisiae Deltasiw14 disruptant exhibits caffeine sensitivity. To understand the function of Siw14, double disruptants for SIW14 and each of 102 viable protein kinases (PKase) genes were constructed and examined for suppression of caffeine sensitivity based on the premise that the sensitivity was caused either by accumulation of an unknown phosphorylated Siw14 substrate(s) or by depletion of an unphosphorylated substrate(s) of Siw14 in the Deltasiw14 disruptant. Among 102 pkase disruptions, only one, Deltanpr1, suppressed the caffeine sensitivity of the Deltasiw14 disruptant. Because Gln3 (a phosphorylated transcriptional activator)-dependent transcription is induced by disruption of NPR1, we further examined the effect of disruption and overexpression of GLN3 on the caffeine sensitivity of the Deltasiw14 disruptant. Disruption of GLN3 was found to partially suppress the caffeine sensitivity of the Deltasiw14 disruptant, while overexpression of GLN3 in wild-type cells caused caffeine sensitivity, providing the first evidence that Siw14 functions in the Gln3 regulatory network. We also found that, unlike in a wild-type background, Gln3 accumulates in the nucleus whether cells are exposed or not to caffeine in the Deltasiw14 disruptant, and that this nuclear localization was abolished by disruption of NPR1. Interestingly, the level of Gln3 phosphorylation in both the Deltasiw14 and Deltanpr1 disruptants decreased relative to wild type, independent of exposure to caffeine. We conclude that Siw14 controls the intracellular localization of Gln3 in combination with Npr1, and one of the causes for the caffeine sensitivity of the Deltasiw14 disruptant was an accumulation of dephosphorylated Gln3 in the nucleus.

Source : Gene 2008 vol.409 (1 -2), pp 34 - 43

Effects of mannooligosaccharides from coffee mannan on blood pressure in dahl salt-sensitive rats

Hoshino-Takao, I.; Fujii, S.; Ishii, A.; Han, L. K.; Okuda, H.; Kumao, T.

Dahl salt-sensitive (Dahl-S) rats, serving as a model of hereditary hypertension, were used to examine the effect of mannooligosaccharides (MOS) on blood pressure. Dahl-S rats were induced to develop hypertension by administering them with a 1.25% salt solution ad libitum. In a 10-wk experimental period, the Dahl-S control and MOS groups developed and maintained significantly higher blood pressure than the Dahl salt-resistant normal control group. The MOS group showed a significantly lower blood pressure than the Dahl-S control group after 5-wk of treatment (p<0.05). In addition, the serum aldosterone level of the MOS group significantly decreased (p<0.05). The findings of this study using a model of hypertensive rats suggest that MOS are able to suppress an elevation in blood pressure.

Source : J Nutr Sci Vitaminol (Tokyo) 2008 vol.54 (2), pp 181 - 184

Effects of coffee and its chemopreventive components kahweol and cafestol on cytochrome P450 and sulfotransferase in rat liver

Huber, W. W.; Rossmanith, W.; Grusch, M.; Haslinger, E.; Prustomersky, S.; Peter-Vorosmarty, B.;
Parzefall, W.; Scharf, G.; Schulte-Hermann, R.

Coffee drinking appears to reduce cancer risk in liver and colon. Such chemoprevention may be caused by the diterpenes kahweol and cafestol (K/C) contained in unfiltered beverage. In animals, K/C treatment inhibited the mutagenicity/tumorigenicity of several carcinogens, likely explicable by beneficial modifications of xenobiotic metabolism, particularly by stimulation of carcinogen-detoxifying phase II mechanisms. In the present study, we investigated the influence of K/C on potentially carcinogen-activating hepatic cytochrome P450 (CYP450) and sulfotransferase (SULT). Male F344 rats received 0.2% K/C (1:1) in the diet for 10 days or unfiltered and/or filtered coffee as drinking fluid. Consequently, K/C decreased the metabolism of four resorufin derivatives representing CYP1A1, CYP1A2, CYP2B1, and CYP2B2 activities by approximately 50%. For CYP1A2, inhibition was confirmed at the mRNA level, accompanied by decreased CYP3A9. In contrast to K/C, coffee increased the metabolism of the resorufin derivatives up to 7-fold which was only marginally influenced by filtering. CYP2E1 activity and mRNA remained unchanged by K/C and coffee. K/C but not coffee decreased SULT by approximately 25%. In summary, K/C inhibited CYP450s by tendency but not universally. Inhibition of CYP450 and SULT may contribute to chemoprevention with K/C but involvement in the protection of coffee drinkers is unlikely. The data confirm that the effects of complex mixtures may deviate from those of their putatively active components.

Source : Food Chem Toxicol 2008 vol.46 (4), pp 1230 - 1238

Identification of novel genes involved in the synergistic antitumor effect of caffeine in osteosarcoma cells using cDNA macroarray

51. Ii, S.; Ueda, Y.; Shimazaki, M.; Katsuta, S.; Takazawa, K.; Kanazawa, Y.; Tomita, K.; Tsuchiya, H.

Caffeine enhances the cytocidal effects of DNA-damaging agents. This study investigated genes involved in the synergistic effect of caffeine on osteosarcoma cells using gene-profiling analysis. MATERIALS AND METHODS: Sensitivity to cisplatin and the synergistic effect of caffeine were evaluated in five osteosarcoma cell lines with different p53 gene status. Gene expression profiles were analyzed using cDNA macroarray and verified by real-time RT-PCR. RESULTS: The cell lines were grouped into three types with different cytotoxic patterns. Comparison of profiling data from these groups identified twelve novel genes associated with the synergistic effect of caffeine. Real-time RT-PCR analyses verified up-regulation of two apoptosis-enhancing genes and down-regulation of two interferon-inducible genes related to the synergy of caffeine.

CONCLUSION: These findings provide new insights into the molecular mechanisms of the synergistic effect of caffeine related to p53 gene status in osteosarcoma, providing candidates for an assay of responsiveness to caffeine-potentiated chemotherapy for osteosarcoma.

Source : Anticancer Res 2008 vol.28 (2A), pp 645 - 653 (not available on line)

Ergogenic effects of low doses of caffeine on cycling performance

Jenkins, N. T.; Trilk, J. L.; Singhal, A.; Oconnor, P. J.; Cureton, K. J.

The purpose of this experiment was to learn whether low doses of caffeine have ergogenic, perceptual, and metabolic effects during cycling. To determine the effects of 1, 2, and 3 mg/kg caffeine on cycling performance, differentiated ratings of perceived exertion (D-RPE), quadriceps pain intensity, and metabolic responses to cycling exercise, 13 cyclists exercised on a stationary ergometer for 15 min at 80% VO, then, after 4 min of active recovery, completed a 15-min VO2peak performance ride 60 min after ingesting caffeine or placebo. Work done (kJ/kg) during the performance ride was used as a measure of performance. D-RPE, pain ratings, and expired-gas data were obtained every 3 min, and blood lactate concentrations were obtained at 15 and 30 min. Compared with placebo, caffeine doses of 2 and 3 mg/kg increased performance by 4% (95% CI: 1.0-6.8%, p = .02) and 3% (95% CI: -0.4% to 6.8%, p = .077), respectively. These effects were ergogenic, on average, but varied considerably in magnitude among individual cyclists. There were no effects of caffeine on D-RPE or pain throughout the cycling task. Selected metabolic variables were affected by caffeine, consistent with its known actions. The authors conclude that caffeine preparations of 2 and 3 mg/kg enhanced performance, but future work should aim to explain the considerable interindividual variability of the drug's ergogenic properties.

Source : Int J Sport Nutr Exerc Metab 2008 vol.18 (3), pp 328 - 342

Caffeine consumption and the risk of primary open-angle glaucoma: a prospective cohort study

Kang, J. H.; Willett, W. C.; Rosner, B. A.; Hankinson, S. E.; Pasquale, L. R.

PURPOSE: To investigate whether caffeine, which transiently increases intraocular pressure (IOP) is associated with the risk of primary open-angle glaucoma (POAG). METHODS: A total of 79,120 women from 1980 to 2004 and 42,052 men from 1986 to 2004, who were 40+ years of age, did not have POAG, and reported undergoing eye examinations, were observed. Information on caffeine consumption, potential confounders, and POAG diagnoses were repeatedly updated in validated follow-up questionnaires. One thousand eleven incident POAG cases were confirmed with medical record review. Cohort-specific and pooled analyses across cohorts were conducted to calculate multivariate rate ratios (RRs). RESULTS: Compared with daily intake of less than 150 mg, the pooled multivariate RRs were 1.05 (95% confidence interval [CI], 0.89-1.25) for consumption of 150 to 299 mg/d, 1.19 (95% CI, 0.99-1.43) for 300 to 449 mg/d, 1.13 (95% CI, 0.89-1.43) for 450 to 559 mg/d, and 1.17 (95% CI, 0.90-1.53) for 600+ mg/d (P for trend = 0.11). However, for consumption of five or more cups of caffeinated coffee daily, the RR was 1.61 (95% CI, 1.00-2.59; P for trend = 0.02); tea or caffeinated cola intake were not associated with risk. Greater caffeine intake was more adversely associated with POAG among those reporting a family history of glaucoma, particularly in relation to POAG with elevated IOP (P for trend = 0.0009; P interaction = 0.04).

CONCLUSIONS: Overall caffeine intake was not associated with increased risk of POAG. However, in secondary analyses, caffeine appeared to elevate risk of high-tension POAG among those with a family history of glaucoma. This result may be due to chance, but warrants further study.

Source : Invest Ophthalmol Vis Sci 2008 vol.49 (5), pp 1924 - 1931

Caffeine-inducible ATP release is mediated by Ca2+-signal transducing system from the endoplasmic reticulum to mitochondria

Katsuragi, T.; Sato, C.; Usune, S.; Ueno, S.; Segawa, M.; Migita, K.

Adenosine triphosphate (ATP) is released as an autocrine/paracrine signal from a variety of cells. The present study was undertaken to clarify the Ca(2+)-signal pathway involved in the caffeine-inducible release of ATP from cultured smooth muscle cells (SMC). The release of ATP induced by caffeine (3 mM) was almost completely inhibited by ryanodine and tetracaine, but not by 2-APB, thus being mediated by ryanodine receptors (RyR). The expression of messenger RNA from only RyR-2 was detected in the cells. Furthermore, the induced release was attenuated by mitochondrial inhibitors, rotenone and oligomycin and by Cl(-) channel blockers, niflumic acid, and 5-nitro-2-(3-phenylpropylamino)-benzoic acid. Increase in Ca(2+)-signals with fluo 4 and rhod-2 caused by caffeine were reduced by tetracaine and oligomycin plus carbonyl cyanide m-chlorophenylhydrazone, respectively. A close spatial relation between the endoplasmic reticulum (ER) and mitochondria was electromicroscopically observed in the SMC, supporting the existence of a Ca(2+)-signaling bridge on both the organelli. These results suggest that caffeine stimulates ryanodine receptor (RyR-2) and facilitates a Ca(2+)-signal transducing system from ER to mitochondria, and then, the signal appears to accelerate the ATP synthesis in mitochondria. In addition, the mitochondrial event may lead further cell signaling to the cell membrane and activates Cl(-) channels, resulting in the extracellular release of cytosolic ATP.

Source : Naunyn Schmiedebergs Arch Pharmacol 2008 vol.378 (1), pp 93 - 101

Case-control study of coffee consumption and the risk of endometrial endometrioid adenocarcinoma

Koizumi, T.; Nakaya, N.; Okamura, C.; Sato, Y.; Shimazu, T.; Nagase, S.; Niikura, H.; Kuriyama, S.; Tase, T.; Ito, K.; Tsubono, Y.; Okamura, K.; Yaegashi, N.; Tsuji, I.

This study examined the association between coffee consumption and the risk of endometrial endometrioid adenocarcinoma (EEA) in Japan by a case-control design. The cases consisted of 107 women less than 80 years of age from two medical centers who had been histopathologically diagnosed to have EEA. The controls, selected from the participants of a cancer-screening program, were 214 women, with two controls selected for each case (matched for age and for area of residence). A self-administered questionnaire containing questions to determine dietary and beverage consumption, as well as reproductive history, was distributed to the cases and controls. Conditional logistic regression analysis was used to estimate the odds ratio (OR) of EEA for three levels of coffee consumption with adjustment for potential confounding factors. The multivariate-adjusted OR of EEA for individuals in the highest tertile of coffee consumption (2 to 3 cups or more/day) was 0.4 [95% confidence interval (CI), 0.2-0.9], and that of cases in the intermediate tertile (5 to 6 times/week-1 cup/day) was 0.6 (95% CI, 0.3-1.2), relative to the individuals in the lowest tertile of coffee consumption (3 to 4 times or less/week) (P for trend=0.014). The above association was observed in postmenopausal women (P for trend=0.016), but not inpremenopausal women (P for trend=0.90). This study thus revealed an inverse dose-response relationship between coffee consumption and the risk of EEA, and its strong association in postmenopausal women but not in premenopausal women.

Source : Eur J Cancer Prev 2008 vol.17 (4), pp 358 - 363

Coffee and tea consumption and risk of stroke subtypes in male smokers

Larsson, S. C.; Mannisto, S.; Virtanen, M. J.; Kontto, J.; Albanes, D.; Virtamo, J.

Coffee and tea consumption could potentially reduce the risk of stroke because these beverages have antioxidant properties, and coffee may improve insulin sensitivity. We examined the associations of coffee and tea consumption with risk of stroke subtypes. METHODS: We used prospective data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a cohort study of 26 556 male Finnish smokers aged 50 to 69 years without a history of stroke at baseline. Coffee and tea consumption was assessed at baseline using a validated food-frequency questionnaire. During a mean follow-up of 13.6 years, from 1985 through December 2004, 2702 cerebral infarctions, 383 intracerebral hemorrhages, and 196 subarachnoid hemorrhages were ascertained from national registries. RESULTS: After adjustment for age and cardiovascular risk factors, both consumption of coffee and tea was statistically significantly inversely associated with the risk of cerebral infarction but not intracerebral or subarachnoid hemorrhage. The multivariate relative risk of cerebral infarction for men in the highest category of coffee consumption (>/=8 cups/d) was 0.77 (95% CI, 0.66 to 0.90; P for trend <0.001) compared with those in the lowest category (<2 cups/d). The corresponding relative risk comparing men in the highest category of tea consumption (>/=2 cups/d) with those in the lowest category (nondrinkers) was 0.79 (95% CI, 0.68 to 0.92; P for trend=0.002).

CONCLUSIONS: These results suggest that high consumption of coffee and tea may reduce the risk of cerebral infarction among men, independent of known cardiovascular risk factors.

Source : Stroke 2008 vol.39 (6), pp 1681 - 1687

Chronic but not acute treatment with caffeine attenuates traumatic brain injury in the mouse cortical

Li, W.; Dai, S.; An, J.; Li, P.; Chen, X.; Xiong, R.; Liu, P.; Wang, H.; Zhao, Y.; Zhu, M.; Liu, X.; Zhu, P.; Chen, J. F.; Zhou, Y.

Caffeine, the most consumed psychoactive drug and non-specific adenosine receptor antagonist, has recently been shown to exert a neuroprotective effect against brain injury in animal models of Parkinson's disease (PD) and stroke. However, the effects of caffeine on traumatic brain injury (TBI) are not known. In this study, we investigated the effects of acute and chronic caffeine treatment on brain injury in a cortical-impact model of TBI in mice. Following TBI, neurological deficits, cerebral edema, as well as inflammatory cell infiltration were all significantly attenuated in mice pretreated chronically (for 3 weeks) with caffeine in drinking water compared with the mice pretreated with saline. Furthermore, we found that chronic caffeine treatment attenuated glutamate release and inflammatory cytokine production, effects that were correlated with an upregulation of brain A1 receptor mRNA. By contrast, acute treatment with caffeine (i.p. injection, 30 min before TBI) was not effective in protecting against TBI-induced brain injury. These results suggest that chronic (but not acute) caffeine treatment attenuates brain injury, possibly by A1 receptor-mediated suppression of glutamate release and inhibition of excessive inflammatory cytokine production. These results highlight the potential benefit of chronic caffeine intake for preventing TBI and provide a rationale for the epidemiological investigation of the potential association between TBI and human caffeine intake.

Source : Neuroscience 2008 vol. 151 (4), pp 1198 - 1207

Effects of caffeine on anorectal manometric findings

Lohsiriwat, S.; Kongmuang, P.; Leelakusolvong, S.

This study was designed to evaluate the effects of caffeine on anorectal function by anorectal manometry. METHODS: Ten healthy subjects were studied. They drank 200 ml of water and later 200 ml of a solution that contained caffeine 3.5 mg/kg body weight. The anorectal manometric study was divided into three periods: basal, water, and caffeine; each period lasted 45 minutes. RESULTS: After the ingestion of water, the basal anal sphincter pressure showed no change during the 45-minute recording, whereas after caffeine consumption the basal anal sphincter pressure increased at 10 minutes (P = 0.047) and 15 minutes (P = 0.037). The average basal anal sphincter pressure throughout the 45 minutes was significantly higher after caffeine ingestion than after water (P = 0.013). After caffeine intake, the maximum squeeze pressure increased significantly (P = 0.017) compared with the basal period. Both water and caffeine consumption caused a decrease in the rectal sensory threshold for the desire to defecate.

CONCLUSIONS: Caffeine 3.5 mg/kg body weight in 200 ml of water resulted in stronger anal sphincter contractions both at basal period and during voluntary squeeze. The sensory threshold was also decreased, leading to an earlier desire to defecate. Caffeine consumption may result in an earlier desire to defecate, leading to defecation if the anal sphincter can relax voluntarily

Source : Dis Colon Rectum 2008 vol.51 (6), pp 928 - 931

The relationship of coffee consumption with mortality

Lopez-Garcia, E.; van Dam, R. M.; Li, T. Y.; Rodriguez-Artalejo, F.; Hu, F. B.

Coffee consumption has been linked to various beneficial and detrimental health effects, but data on its relation with mortality are sparse. OBJECTIVE: To assess the association between coffee consumption and mortality from cardiovascular disease (CVD), cancer, and all causes during 18 years of follow-up in men and 24 years of follow-up in women. DESIGN: Sex-specific Cox proportional hazard models were used to investigate the association between coffee consumption and incidence of all-cause and disease-specific mortality in a prospective cohort study. SETTING: Health Professionals Follow-up Study and Nurses' Health Study. PARTICIPANTS: 41,736 men and 86,214 women with no history of CVD or cancer at baseline. MEASUREMENTS: Coffee consumption was assessed first in 1986 for men and in 1980 for women and then every 2 to 4 years through 2004. Investigators documented 6888 deaths (2049 due to CVD and 2491 due to cancer) among men and 11,095 deaths (2368 due to CVD and 5011 due to cancer) among women. RESULTS: After adjustment for age, smoking, and other CVD and cancer risk factors, the relative risks for all-cause mortality in men across categories of coffee consumption (<1 cup per month, 1 cup per month to 4 cups per week, 5 to 7 cups per week, 2 to 3 cups per day, 4 to 5 cups per day, and >or=6 cups per day) were 1.0, 1.07 (95% CI, 0.99 to 1.16), 1.02 (CI, 0.95 to 1.11), 0.97 (CI, 0.89 to 1.05), 0.93 (CI, 0.81 to 1.07), and 0.80 (CI, 0.62 to 1.04), respectively (P for trend = 0.008). For women, the relative risks were 1.0, 0.98 (CI, 0.91 to 1.05), 0.93 (CI, 0.87 to 0.98), 0.82 (CI, 0.77 to 0.87), 0.74 (CI, 0.68 to 0.81), and 0.83 (CI, 0.73 to 0.95), respectively (P for trend < 0.001). This inverse association was mainly due to a moderately reduced risk for CVD mortality and was independent of caffeine intake. By contrast, coffee consumption was not statistically significantly associated with risk for cancer death after adjustment for potential confounders. Decaffeinated coffee consumption was associated with a small reduction in all-cause and CVD mortality. LIMITATION: Coffee consumption was estimated from self-report; thus, some measurement error is inevitable.

CONCLUSION: Regular coffee consumption was not associated with an increased mortality rate in either men or women. The possibility of a modest benefit of coffee consumption on all-cause and CVD mortality needs to be further investigated.

Source : Ann Intern Med 2008 vol.148 (12), pp 904 - 914

Caffeine use: association with nicotine use, aggression, and other psychopathology in psychiatric and pediatric outpatient adolescents

Martin, C. A.; Cook, C.; Woodring, J. H.; Burkhardt, G.; Guenthner, G.; Omar, H. A.; Kelly, T. H.

The objective of this study was to evaluate the relationship between caffeine use, other drug use, and psychopathology in adolescents, using self-report measures. The study group consisted of 132 adolescents (average age 14.01 "b 2.06 years, 52% female, 19% African American, 5% other categories, 76% Caucasian). Most (47%) were recruited from a child psychiatry clinic with emphasis on youth with disruptive disorders, with 35% from an adolescent pediatric clinic with emphasis on prevention of risk-taking behavior and 18% from a pediatric clinic for families with limited resources. Subjects were consecutively recruited before or after regular clinic visits. Consent was obtained from parents and assent from the youth. High caffeine consumption was associated with daily cigarette use; aggressive behavior; conduct, attention deficit/hyperactivity, and social problems; and increased somatic complaints in adolescents.

Source : Scientific World J 2008 vol.8, pp 512 - 516

Caffeine markedly sensitizes human mesothelioma cell lines to pemetrexed

Min, S. H.; Goldman, I. D.; Zhao, R.

Pemetrexed is a new generation antifolate approved for the treatment of mesothelioma and non-small cell lung cancer. Caffeine is known to augment radiation or chemotherapeutic drug-induced cell killing. The current study addresses the impact of caffeine on the activity of pemetrexed in mesothelioma cell lines. Caffeine enhanced pemetrexed activity in all four mesothelioma cell lines tested (H2052, H2373, H28 and MSTO-211H). Caffeine sensitized H2052 cells in a dose- and schedule-dependent manner, and was associated with a markedly decreased clonogenic survival. Caffeine sensitization occurred only in cells subjected to pulse, but not continuous, exposure to pemetrexed. Similar pemetrexed sensitization was also observed with the clinically better tolerated caffeine analog, theobromine. Pemetrexed sensitization by caffeine was associated with an increase in pemetrexed-induced phosphorylation of ataxia-telangiectasia-mutated (ATM) and Chk1. These data indicate that caffeine and its analog, theobromine, may be a useful approach to enhance pemetrexed-based chemotherapy.

Source : Cancer Chemother Pharmacol 2008 vol.61 (5), pp 819 - 827

Caffeinated coffee consumption impairs blood glucose homeostasis in response to high and low glycemic index meals in healthy men

Moisey, L. L.; Kacker, S.; Bickerton, A. C.; Robinson, L. E.; Graham, T. E.

The ingestion of caffeine (5 mg/kg body weight) and a 75-g oral glucose load has been shown to elicit an acute insulin-insensitive environment in healthy and obese individuals and in those with type 2 diabetes. OBJECTIVE: In this study we investigated whether a similar impairment in blood glucose management exists when coffee and foods typical of a Western diet were used in a similar protocol. DESIGN: Ten healthy men underwent 4 trials in a randomized order. They ingested caffeinated (5 mg/kg) coffee (CC) or the same volume of decaffeinated coffee (DC) followed 1 h later by either a high or low glycemic index (GI) cereal (providing 75 g of carbohydrate) mixed meal tolerance test. RESULTS: CC with the high GI meal resulted in 147%, 29%, and 40% greater areas under the curve for glucose (P < 0.001), insulin (NS), and C-peptide (P < 0.001), respectively, compared with the values for DC. Similarly, with the low GI treatment, CC elicited 216%, 44%, and 36% greater areas under the curve for glucose (P < 0.001), insulin (P < 0.01), and C-peptide (P < 0.01), respectively. Insulin sensitivity was significantly reduced (40%) with the high GI treatment after CC was ingested compared with DC; with the low GI treatment, CC ingestion resulted in a 29% decrease in insulin sensitivity, although this difference was not significant.

CONCLUSION: The ingestion of CC with either a high or low GI meal significantly impairs acute blood glucose management and insulin sensitivity compared with ingestion of DC. Future investigations are warranted to determine whether CC is a risk factor for insulin resistance.

Source : Am J Clin Nutr 2008 vol.87 (5), pp 1254 - 1261

Modest maternal caffeine exposure affects developing embryonic cardiovascular function and growth

Momoi, N.; Tinney, J. P.; Liu, L. J.; Elshershari, H.; Hoffmann, P. J.; Ralphe, J. C.; Keller, B. B.; Tobita, K.

Caffeine consumption during pregnancy is reported to increase the risk of in utero growth restriction and spontaneous abortion. In the present study, we tested the hypothesis that modest maternal caffeine exposure affects in utero developing embryonic cardiovascular (CV) function and growth without altering maternal hemodynamics. Caffeine (10 mg.kg(-1).day(-1) subcutaneous) was administered daily to pregnant CD-1 mice from embryonic days (EDs) 9.5 to 18.5 of a 21-day gestation. We assessed maternal and embryonic CV function at baseline and at peak maternal serum caffeine concentration using high-resolution echocardiography on EDs 9.5, 11.5, 13.5, and 18.5. Maternal caffeine exposure did not influence maternal body weight gain, maternal CV function, or embryo resorption. However, crown-rump length and body weight were reduced in maternal caffeine treated embryos by ED 18.5 (P < 0.05). At peak maternal serum caffeine concentration, embryonic carotid artery, dorsal aorta, and umbilical artery flows transiently decreased from baseline at ED 11.5 (P < 0.05). By ED 13.5, embryonic aortic and umbilical artery flows were insensitive to the peak maternal caffeine concentration; however, the carotid artery flow remained affected. By ED 18.5, baseline embryonic carotid artery flow increased and descending aortic flow decreased versus non-caffeine-exposed embryos. Maternal treatment with the adenosine A(2A) receptor inhibitor reproduced the embryonic hemodynamic effects of maternal caffeine exposure. Adenosine A(2A) receptor gene expression levels of ED 11.5 embryo and ED 18.5 uterus were decreased. Results suggest that modest maternal caffeine exposure has adverse effects on developing embryonic CV function and growth, possibly mediated via adenosine A(2A) receptor blockade.

Source : Am J Physiol Heart Circ Physiol 2008 vol.294 (5), pp H2248 - H2256

Caffeine activates the PI3K/Akt pathway and prevents apoptotic cell death in a Parkinson\'s disease model of SH-SY5Y cells

Nakaso, K.; Ito, S.; Nakashima, K.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. Recent epidemiological studies suggest that caffeine, one of the major components of coffee, has a protective effect against developing PD. However, the detailed mechanisms of how caffeine suppresses neuronal death have not been fully elucidated. We investigated the cytoprotective mechanisms of caffeine using human dopaminergic neuroblastoma SH-SY5Y cells as a PD model. Caffeine prevented the apoptotic cell death induced by serum/retinoic acid (RA) deprivation, MPP+, rotenone, and 6-OHDA in SH-SY5Y cells in a dose dependent manner. Caffeine lowered caspase-3 activity induced by serum/RA deprivation and 6-OHDA administration, and also decreased the number of apoptotic condensed and/or fragmented nuclei. Akt was phosphorylated 60 min after caffeine administration in a dose dependent manner; PI3K inhibitors, wortmannin and LY294002 canceled this cytoprotective effect of caffeine. On the other hand, MAPKs such as Erk1/2, p38, or JNK were not activated by caffeine. These results suggest that caffeine has a cytoprotective effect due to the activation of the PI3K/Akt pathways in SH-SY5Y cells.

Source : Neurosci Lett 2008 vol.432 (2), pp 146 - 150

Caffeinated cocktails: energy drink consumption, high-risk drinking, and alcohol-related consequences among college students

O'Brien, M. C.; McCoy, T. P.; Rhodes, S. D.; Wagoner, A.; Wolfson, M.

The consumption of alcohol mixed with energy drinks (AmED) is popular on college campuses in the United States. Limited research suggests that energy drink consumption lessens subjective intoxication in persons who also have consumed alcohol. This study examines the relationship between energy drink use, high-risk drinking behavior, and alcohol-related consequences. METHODS: In Fall 2006, a Web-based survey was conducted in a stratified random sample of 4,271 college students from 10 universities in North Carolina. RESULTS: A total of 697 students (24% of past 30-day drinkers) reported consuming AmED in the past 30 days. Students who were male, white, intramural athletes, fraternity or sorority members or pledges, and younger were significantly more likely to consume AmED. In multivariable analyses, consumption of AmED was associated with increased heavy episodic drinking
(6.4 days vs. 3.4 days on average; p < 0.001) and twice as many episodes of weekly drunkenness (1.4 days/week vs. 0.73 days/week; p < 0.001). Students who reported consuming AmED had significantly higher prevalence of alcohol-related consequences, including being taken advantage of sexually, taking advantage of another sexually, riding with an intoxicated driver, being physically hurt or injured, and requiring medical treatment (p < 0.05). The effect of consuming AmED on driving while intoxicated depended on a student's reported typical alcohol consumption (interaction p = 0.027).

CONCLUSIONS: Almost one-quarter of college student current drinkers reported mixing alcohol with energy drinks. These students are at increased risk for alcohol-related consequences, even after adjusting for the amount of alcohol consumed. Further research is necessary to understand this association and to develop targeted interventions to reduce risk.

Source : Acad Emerg Med 2008 vol.15 (5), pp 453 - 460

Caffeine has a small effect on 5-km running performance of well-trained and recreational runners

O'Rourke, M. P.; O'Brien, B. J.; Knez, W. L.; Paton, C. D.

The purpose of this study was to investigate if caffeine ingestion improves 5-km time-trial performance in well-trained and recreational runners. Using a double-blind placebo-controlled design, 15 well-trained and 15 recreational runners completed two randomized 5-km time-trials, after ingestion of either 5mgkg(-1) of caffeine or a placebo. Caffeine ingestion significantly improved 5-km running performance in both the well-trained and recreational runners. In comparison to the placebo trial, the caffeine trial resulted in 1.1% (90% CI 0.4-1.6) and 1.0% (0.2-2%) faster times for the well-trained and recreational runners. Reliability testing of the recreational runners indicated a test-retest error of measurement of 1.4%. We conclude that caffeine ingestion is likely to produce small but significant gains in 5-km running performance for both well-trained and recreational runners.

Source : J Sci Med Sport 2008 vol.11 (2), pp 231 - 233

Caffeine inhibits the proliferation of liver cancer cells and activates the MEK/ERK/EGFR signalling pathway

Okano, J.; Nagahara, T.; Matsumoto, K.; Murawaki, Y.

Caffeine has been reported to prevent hepatocarcinogenesis. We investigated the molecular mechanisms by which caffeine inhibits the growth of hepatocellular carcinoma (HCC) cells. We found that caffeine inhibited the proliferation of HCC cells via cell cycle arrest independent of apoptosis. We revealed a novel signalling axis for caffeine involving activation of the mitogen-activated ERK-regulating kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway that resulted in the downstream up-regulation of epidermal growth factor receptor (EGFR), although the MEK/ERK/EGFR signalling pathway was not involved in the growth inhibitory effect of caffeine. Our data reveal that caffeine could be a promising candidate for the treatment of patients with HCC.

Source : Basic Clin Pharmacol Toxicol 2008 vol.102 (6), pp 543 - 551

The role of hair follicles in the percutaneous absorption of caffeine

Otberg, N.; Patzelt, A.; Rasulev, U.; Hagemeister, T.; Linscheid, M.; Sinkgraven, R.; Sterry, W.; Lademann,J.

In recent years, it has been suggested that hair follicles represent important shunt routes into the skin for drugs and chemicals [1-3]. * In vitro studies have shown the importance of skin appendages for skin penetration by hydrophilic compounds [4]. Investigation of follicular penetration in vivo has been difficult due to the absence of appropriate analytical methods or suitable animal model systems. * Recently, a new method was described that quantifies follicular penetration in vivo by using selective closure of hair follicles [5]. * Caffeine is frequently used in skin penetration experiments as a model for highly water-soluble compounds. Occlusion [6] and skin thickness [7] seem to have little influence on the penetration of caffeine. However, percutaneous absorption rates for caffeine exhibit regional skin differences in humans in vivo[1]. WHAT THIS STUDY ADDS: * The results of the present study demonstrate that a fast drug delivery of caffeine occurs through shunt routes. Therefore, hair follicles are considerable weak spots in our protective sheath against penetration into the body by hydrophilic substances. * We showed that there is a quantitative distinction between follicular penetration and interfollicular diffusion of caffeine in vivo. * These findings are of importance for the development and optimization of topically applied drugs and cosmetics. In addition, such properties must be considered in the development of skin protection measures. AIMS: The skin and its appendages are our protective shield against the environment and are necessary for the maintenance of homeostasis. Hypotheses concerning the penetration of substances into the skin have assumed diffusion through the lipid domains of the stratum corneum. It is believed that while hair follicles represent a weakness in the shield, they play a subordinate role in the percutaneous penetration processes. Previous investigation of follicular penetration has mostly addressed methodical and technical problems. Our study utilized a selective closure technique of hair follicle orifices in vivo, for the comparison of interfollicular and follicular absorption rates of caffeine in humans. METHODS: Every single hair follicle within a delimited area of skin was blocked with a microdrop of a special varnish-wax-mixture in vivo. Caffeine in solution was topically applied and transcutaneous absorption into the blood was measured by a new surface ionization mass spectrometry (SI/MS) technique, which enabled a clear distinction to be made between interfollicular and follicular penetration of a topically applied substance. RESULTS: Caffeine (3.75 ng ml(-1)) was detected in blood samples, 5 min after topical application, when the follicles remained open. When the follicles were blocked, caffeine was detectable after 20 min (2.45 ng ml(-1)). Highest values (11.75 ng caffeine ml(-1)) were found 1 h after application when the follicles were open.

CONCLUSIONS: Our findings demonstrate that hair follicles are considerable weak spots in our protective sheath against certain hydrophilic drugs and may allow a fast delivery of topically applied substances.

Source : Br J Clin Pharmacol 2008 vol.65 (4), pp 488 - 492

The impact of caffeine on mood, cognitive function, performance and hydration: a review of benefits and risks

Ruxton, C. H. S.

Caffeine, mainly from tea, coffee, cocoa products and colas, is the world's most consumed psychoactive substance, but there are concerns that excessive caffeine intakes increase the risks of dehydration, anxiety, headache and sleep disturbances. This paper reviews published results from 41 controlled trials into the benefits and risks of caffeine consumption. Most studies reported benefits from low-moderate (37.5-450 mg/day) caffeine intakes, studies on hydration indicating that caffeine intakes up to 400 mg/day did not produce dehydration. This level of caffeine equates to 1-8 cups of tea, or 0.3-4 cups of brewed coffee, per day.

Source : BNF Nutrition Bulletin 2008 vol.33 (1), pp 15-25

Increase of dopamine D2(High) receptors in the striatum of rats sensitized to caffeine motor effects

Simola, N.; Morelli, M.; Seeman, P.

It has been previously demonstrated how rats can develop behavioral dopamine supersensitivity after long-term administration of caffeine. Since behavioral dopamine supersensitivity in rats is usually accompanied by an elevation in striatal dopamine D2(High) receptors, we examined whether alterations in D2(High) receptors occurred in the striatum of rats administered caffeine according to a regimen capable of eliciting behavioral dopamine supersensitivity (15 mg/kg i.p. every other day for 14 days). An increase of 126% in striatal D2(High) receptors was found in caffeine-sensitized rats. This marked elevation in D2(High) receptors may account for the caffeine-induced behavioral dopamine supersensitivity and may help elucidate the interactions between caffeine and dopamine neurotransmission.

Source : Synapse 2008 vol. 62 (5), pp 394 - 397

Caffeine use in sports: considerations for the athlete

Sokmen, B.; Armstrong, L. E.; Kraemer, W. J.; Casa, D. J.; Dias, J. C.; Judelson, D. A.; Maresh, C. M.

The ergogenic effects of caffeine on athletic performance have been shown in many studies, and its broad range of metabolic, hormonal, and physiologic effects has been recorded, as this review of the literature shows. However, few caffeine studies have been published to include cognitive and physiologic considerations for the athlete. The following practical recommendations consider the global effects of caffeine on the body: Lower doses can be as effective as higher doses during exercise performance without any negative coincidence; after a period of cessation, restarting caffeine intake at a low amount before performance can provide the same ergogenic effects as acute intake; caffeine can be taken gradually at low doses to avoid tolerance during the course of 3 or 4 days, just before intense training to sustain exercise intensity; and caffeine can improve cognitive aspects of performance, such as concentration, when an athlete has not slept well. Athletes and coaches also must consider how a person's body size, age, gender, previous use, level of tolerance, and the dose itself all influence the ergogenic effects of caffeine on sports performance.

Source : J Strength Cond Res 2008 vol.22 (3), pp 978 - 986

Development and initial validation of a caffeine craving

West, O.; Roderique-Davies, G.

Craving for caffeine has received little empirical attention, despite considerable research into the potential for caffeine dependence. The main aim of this study was to develop, and initially validate, a multi-item, multidimensional instrument to measure cravings for caffeine. Participants were 189 caffeine consumers who completed the Questionnaire of Caffeine Cravings, which was based on the Questionnaire of Smoking Urges (QSU), in one of five naturally occurring periods of abstinence; 1-15 min; 16-120 mins; 3¬7 h; 12-48 h and +48 h. Exploratory factor analysis suggested a three-factor solution best described the data; Factor 1 reflected strong desires, intentions and positive reinforcement; Factor 2 reflected mild/general positive and negative reinforcement and Factor 3 reflected functional/mood-based negative reinforcement. Significantly higher Factor 1 and Factor 2 scores were recorded for high frequency users; significantly higher Factor 1 and Factor 3 scores were recorded as a function of increased levels of dependence. Duration of abstinence did not significantly effect cravings across all three factors. Regression analyses suggested level of dependence best predicted both current cravings and frequency of daily use. These findings suggest caffeine cravings may be conceptualized multidimensionally and further validates the use of multidimensional, multi-item instruments. Cravings for caffeine may manifest and be detected across varying levels of dependence and, frequency of use and independently of duration of abstinence.

Source : J Psychopharmacol 2008 vol.22 (1), pp 80 - 91

The effect of ephedra and caffeine on maximal strength and power in resistance-trained athletes

Williams, A. D.; Cribb, P. J.; Cooke, M. B.; Hayes, A.

Caffeine and ephedrine-related alkaloids recently have been removed from International Olympic Committee banned substances lists, whereas ephedrine itself is now permissible at urinary concentrations less than 10 mug.mL. The changes to the list may contribute to an increased use of caffeine and ephedra as ergogenic aids by athletes. Consequently, we sought to investigate the effects of ingesting caffeine (C) or a combination of ephedra and caffeine (C + E) on muscular strength and anaerobic power using a double-blind, crossover design. Forty-five minutes after ingesting a glucose placebo (P: 300 mg), C (300 mg) or C + E (300 mg + 60 mg), 9 resistance-trained male participants were tested for maximal strength by bench press [BP; 1 repetition maximum (1RM)] and latissimus dorsi pull down (LP; 1RM). Subjects also performed repeated repetitions at 80% of 1RM on both BP and LP until exhaustion. After this test, subjects underwent a 30-second Wingate test to determine peak anaerobic cycling power, mean power, and fatigue index. Although subjects reported increased alertness and enhanced mood after supplementation with caffeine and ephedra, there were no significant differences between any of the treatments in muscle strength, muscle endurance, or peak anaerobic power. Our results do not support the contention that supplementation with ephedra or caffeine will enhance either muscle strength or anaerobic exercise performance.

Source : J Strength Cond Res 2008 vol.22 (2), pp 464 - 470

Coffee consumption is associated with higher plasma adiponectin concentrations in women with or without type 2 diabetes: a prospective cohort study

Williams, C. J.; Fargnoli, J. L.; Hwang, J. J.; van Dam, R. M.; Blackburn, G. L.; Hu, F. B.; Mantzoros, C. S.

To test whether the beneficial effects of coffee consumption in metabolism might be explained by changes in circulating levels of adiponectin, we evaluated self-reported habitual coffee and tea consumption and caffeine intake as predictors of plasma adiponectin concentrations among 982 diabetic and 1,058 nondiabetic women without cardiovascular disease from the Nurses' Health Study. Women with and without diabetes who drank >or=4 cups of coffee per day had significantly higher adiponectin concentrations than those who didn't drink coffee regularly (7.7 vs. 6.1 microg/ml, respectively, in diabetic women, P = 0.004; 15.0 vs. 13.2 microg/ml in nondiabetic women, P = 0.04). Similar associations were observed for caffeine intake. We confirm previously reported inverse associations of coffee consumption with inflammatory markers, C-reactive protein, and tumor necrosis factor-alpha receptor II. Adjustment for adiponectin did not weaken these associations, and adjustment for inflammatory markers did not attenuate the association between coffee consumption and adiponectin concentrations. High consumption of caffeine-containing coffee is associated with higher adiponectin and lower inflammatory marker concentrations.

Source : Diabetes Care vol.31 (3), pp 504 - 507

Caffeine overcomes genistein-induced G2/M cell cycle arrest in breast cancer cells

Zhong, Li; Wen, Liu; Baoqing, Mo; Chunyan, Hu; Huaqing, Liu; Hong, Qi; Xinru, Wang; Jida, Xu

Although inhibition of tumour cell growth by genistein is mediated by different types of cell cycle arrest, its regulation of genes related to the cell cycle is not clear. In this study, genistein caused a concn.-dependent growth inhibition in the hormone-independent cell line MDA-MB-435S. Flow cytometric analysis showed that genistein induced a concn.-dependent accumulation of cells in the G2/M phase of the cell cycle. Caffeine enhanced the inhibition of cell proliferation induced by genistein. Caffeine alone did not have an appreciable effect on the phases of the cell cycle, but caffeine at 3mM completely eliminated genistein-induced G2/M cell cycle arrest. cDNA microarrays were used to investigate the mechanism of genistein-induced, caffeine-negated G2/M arrest. 12 genes were identified which had opposite responses to genistein and caffeine treatments. Among these, 5 genes were upregulated by genistein and downregulated by caffeine; 7 genes were downregulated by genistein and upregulated by caffeine. Reversal by caffeine of genistein-induced G2/M phase arrest in breast cancer cell lines could increase their sensitivity to genistein and enhance genistein-induced inhibition of cell growth. Genes that have opposite responses to genistein and caffeine may be involved in regulation of the G2/M phase of the cell cycle.

Source : Nutrition and Cancer 2008 vol.60 (3), pp 382 - 388

Increased emotional reactivity in rats following exposure to caffeine during adolescence

Anderson, N. L.; Hughes, R. N.

From 45 to 55 days after birth, male and female rats were treated via daily intraperitoneal injections with either isotonic saline, or 15 or 30 mg/kg caffeine. When 72-82 and 112-122 days old, their activity and emotional reactivity were assessed by means of frequencies of rearing, ambulation, immobility, defecation and urination recorded in an open field, as well as their occupancy of corners and center squares of the field, and their partial emergence and latencies to fully emerge from a small darkened chamber into a brightly lit arena. Rats treated with caffeine were probably more emotionally reactive than untreated controls as suggested by more immobility and defecation and urination. There were also effects on rearing and ambulation that might have arisen from increased impulsivity. Further evidence of caffeine treatment-induced higher emotional reactivity was found in the heavier adrenal glands of a small number of 10 months-old males. This occurred in the absence of any caffeine treatment effects on spatial reference memory measured by ability to identify a novel Y-maze arm. Changes between the two testing ages in rearing and emergence latencies, and sex-dependent changes in ambulation, defecation and corner and center squares occupancy, along with immobility for 30 mg/kg caffeine-treated subjects, were discussed in the light of possible changes in emotional reactivity. Sex differences in open-field rearing and ambulation, and testing age-dependent sex differences in corner and center squares occupancy were ascribed to higher emotional reactivity in males.

Source : Neurotoxicol Teratol 2008 vol.30 (3), pp 195 - 201