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PubMed1996

Anti-genotoxic effects in mice after the interaction between coffee and dietary constituents.

The interaction between coffee (100 mg freeze-dried home brew/kg body weight) and dietary constituents was assessed for anti-genotoxic effects against cyclophosphamide, N-methyl-N-nitro-N- nitrosoguanidine (MNNG), N-nitroso-N-ethylurea, mitomycin C and urethane (URE) in the mouse bone marrow micronucleus test. Combinations of dietary constituents consisting of (1) chlorogenic acid, caffeic acid, ellagic acid and ferulic acid, (2) beta-carotene, curcumin and alpha-tocopherol, (3) chlorogenic acid, curcumin, alpha-tocopherol, anethole and eugenol, and (4) beta-carotene, curcumin, ellagic acid and chlorogenic acid were used in this study. Before the genotoxin was injected i.p., identical groups of mice were orally administered either vehicle control, coffee, dietary constituents, or coffee plus dietary constituents. Co-administration of coffee with the dietary constituents enhanced the anti-genotoxic effect compared with that of either coffee or the dietary constituents alone. Two-factor analysis of variance of the data suggests that there is a significant synergistic interaction between coffee and the dietary constituents for anti-genotoxic effects against MNNG (combination 1 and 2) and URE (combination 4).

Allylbenzene Derivatives↗
PubMedDate not supplied

Effects of coffee on plasma lipids, lipoproteins and apolipoproteins.

The acute effects of coffee, cigarette smoking and alcohol on serum lipids, lipoproteins and thromboxane B2 production by platelets were studied in nine healthy volunteers who were non-drinkers of coffee and alcohol and non-smokers. They received, in a single administration, coffee (containing 200 mg of caffeine), alcohol (0.50 ml/kg body wt), or smoked two cigarettes. No differences were observed between baseline and 15, 60 and 80 min values for plasma cholesterol, triglycerides, HDL cholesterol, plasma apolipoproteins A-I and B and thromboxane B2 production. Chronic coffee consumption also did not affect either plasma lipoprotein profile or the interaction of low density lipoproteins with cellular receptors in a group of healthy individuals. These results suggest that coffee itself does not affect acutely the plasma lipoprotein profile in healthy man. This was also true in heavy coffee drinkers.

Adult↗
PubMed2006

Improvement of hypertension and vascular dysfunction by hydroxyhydroquinone-free coffee in a genetic model of hypertension.

Chlorogenic acid, a polyphenol found in coffee, has antihypertensive actions, but epidemiologic data on the effects of coffee on blood pressure are controversial. Specific coffee components that inhibit the hypotensive effect of chlorogenic acid and the physiologic mechanisms underlying the effects of coffee without these components were investigated. One component, hydroxyhydroquinone (HHQ), inhibited the hypotensive effects of chlorogenic acid in spontaneously hypertensive rats (SHR). The attenuation of hypertension by HHQ-free coffee was associated with nitric oxide, the suppression of mRNA expression of NAD(P)H oxidase, and the improvement in endothelium-dependent vasodilation in the aorta. Thus, HHQ-free coffee might regulate vascular tone by improving the bioavailability of nitric oxide in SHR.

Animals↗
PubMed2005

Coffee consumption reduces the risk of hepatocellular carcinoma independently of its aetiology: a case-control study.

BACKGROUND/AIMS: The role of coffee in the development of hepatocellular carcinoma (HCC) is debated. The aim of this study was to investigate the role of coffee in HCC, taking the main risk factors into account. METHODS: A hospital-based case-control study was conducted in an area of northern Italy. We recruited 250 HCC cases and 500 controls hospitalized for any reasons other than neoplasms, and liver and alcohol-related diseases. Subjects were interviewed on their lifetime history of coffee consumption using a standardized questionnaire. RESULTS: Coffee consumption in the decade before the interview was associated with a decreasing risk of HCC with a clear dose-effect relation. With respect to non-drinking subjects, the odds ratios (ORs) were: 0.8, (95% CI 0.4-1.3) for 1-2 cups/day, 0.4 (95% CI 0.2-0.8) for 3-4 cups/day and 0.3 (95% CI 0.1-0.7) for 5 or more cups/day. The ORs for HCC decreased for drinking >2, compared to 0-2 cups/day of coffee, for an alcohol intake >80 g/day (OR from 5.7 to 3.3), for presence of hepatitis B virus infection (OR from 16.4 to 7.3) or hepatitis C virus infection (OR from 38.2 to 9.0). CONCLUSIONS: Coffee drinking was inversely associated with HCC regardless of its aetiology.

Aged↗
PubMed2002

Dicinnamoylquinides in roasted coffee inhibit the human adenosine transporter.

Preliminary screening of a minor, non-xanthine constituent of roasted coffee, 3,4-diferuloyl-1,5-quinolactone (DIFEQ), showed inhibition of the adenosine transporter at low micromolar concentration. DIFEQ is a neutral derivative of the chlorogenic acids, i.e. isomeric mono- and di-substituted coumaroyl-, caffeoyl-, and feruloyl-esters of quinic acid, formed in the roasting process of coffee. Displacement of the adenosine transporter antagonist [(3)H](S)-(nitrobenzyl)-6-thioinosine binding by DIFEQ in cultured U-937 cell preparations, expressing the human adenosine transporter protein (hENT1), showed a K(i) of 0.96+/-0.13 microM. Extracts of regular and decaffeinated coffee showed binding activities equivalent to 30-40 mg DIFEQ per three cups of coffee. Acute administration of a high dose of DIFEQ (100 mg/kg i.p.) reduced open field locomotion in mice for 20 min in correlation with brain levels of DIFEQ. Both 3,4-dicaffeoyl-1,5-quinide and 3,4-dicoumaroyl-1,5-quinide, two close structural analogs of DIFEQ also present in roasted coffee, showed similar affinities for the adenosine transporter, while the corresponding 3- and 4-mono caffeoyl- and feruloyl-quinides were one to two orders of magnitudes less active. This suggests that 3,4-dicinnamoyl-1,5-quinides in coffee could have the potential to raise extra-cellular adenosine levels, thereby counteracting the stimulant effect of caffeine.

Animals↗
PubMed2003

Coffee and its chemopreventive components Kahweol and Cafestol increase the activity of O6-methylguanine-DNA methyltransferase in rat liver--comparison with phase II xenobiotic metabolism.

A lower rate of colon cancer was observed in consumers of coffee with a high content of the diterpenes Kahweol and Cafestol (K/C). In animal models, K/C have been found to protect against the mutagenic/carcinogenic effects of compounds such as 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), aflatoxin B1, and 7,12-dimethylbenz[a]anthracene. Thus far, such chemoprotection by K/C has been attributed to modifications of xenobiotic metabolism, e.g. enhanced detoxification by UDP-glucuronosyltransferase (UDPGT) and/or glutathione transferase (GST). In the present study, we investigated the potential of several coffee-related treatments (K/C [1:1], Cafestol-alone, Turkish coffee) to modify the expression level of the DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) which is involved in the reversal of the precarcinogenic DNA damage O(6)-alkylguanine induced by alkylating agents. The results show that, in the male F344 rat, K/C and Cafestol increase hepatic MGMT in a dose-dependent manner up to a maximum of 2.6-fold at 0.122% K/C in the feed. Turkish coffee led to enhancements of up to 16%, the more moderate increase being associated with the lower estimated K/C intake through the beverage. In the livers of the rats receiving Turkish coffee, we also found 10-30% increases in several GST-related parameters (overall GST, GST-pi, glutathione, gamma-glutamylcysteine-synthetase) and a two-fold increase in UDPGT activity. Dose-response studies with K/C revealed that MGMT increased in parallel with three of the four GST-related parameters whereas the dose-response curves of UDPGT and of GST-pi activity displayed a steeper slope. Increased expression level of MGMT may extend the antimutagenic/anticarcinogenic potential of coffee components to protection against DNA alkylating agents.

Animals↗
PubMed2001

Coffee enhances the development of 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinomas.

UNLABELLED: In this study, we examined the effect of roasted coffee extract on 7,12-dimethylbenz[a]anthracene (DMBA)-induced buccal pouch carcinogenesis in male Syrian hamsters using lipid peroxidation, reduced glutathione (GSH) and glutathione peroxidase (GPx) activity as biomarkers of chemoprevention. Forty male hamsters were divided into four groups of 10 animals. The right buccal pouches of the animals in Group 1 was painted with a 0.5% solution of DMBA in liquid paraffin three times a week. The animals in Group 2 painted with DMBA as in Group 1, received in addition 2 ml of 8% black coffee extract intragastrically three times a week on days alternate to DMBA application. Group 3 animals received coffee extract as in Group 2. Animals in Group 4 received neither DMBA nor coffee extract and served as control. The hamsters were sacrificed after an experimental period of 14 weeks. Biochemical measurements were carried out on tumour and normal pouch tissues. Administration of roasted coffee extract had no preventive effect on DMBA-induced oral cancer as revealed by the higher mean tumour volume and tumour burden compared to animals painted with DMBA alone. Diminished lipid peroxidation in the oral tumour tissue was accompanied by a significant increase in the levels of GSH and GPx. CONCLUSIONS: The results of the present study suggest that coffee exerts a tumour enhancing effect when administered during DMBA-induced hamster buccal pouch carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2002

Headspace GC and sensory analysis characterization of the influence of different milk additives on the flavor release of coffee beverages.

Previous investigations of coffee flavor have been confined to the analysis of the aroma substances. These investigations showed that about 30 volatile compounds were substantially responsible for the coffee flavor. The aim of this study was to investigate the influence of different milk additives and one coffee whitener on the release of flavor impact compounds from coffee beverages. For the investigation of these effects an external static headspace technique was developed. With this technique the most potent odorants of the coffee beverage were determined. Analyses were performed by gas chromatography/olfactometry, flame ionization detection, and mass spectrometric detection. In addition, sensory studies of the odor profiles were performed. Milk and vegetable products as additives for coffee beverages affected the release of aroma substances in the brew through their lipid, protein, and carbohydrate components. All beverages with an additive showed reduced, but typical, odor profiles for each additive.

Animals↗
PubMed2003

FTIR-ATR analysis of brewed coffee: effect of roasting conditions.

FTIR-ATR was used to study the effect of roasting conditions on the flavor of brewed coffee using Guatemala Antigua coffee beans. The 1800-1680 cm(-1) carbonyl region for vinyl esters/lactones, esters, aldehydes, ketones, and acids was found to provide a flavor-print of the brewed coffee. A study of light, medium, and dark roasts indicated that when the rate of heating to the onset of the first and second cracks was kept constant, the types of carbonyl compounds formed were similar, varying only in their concentration. This difference in concentration is apparently due to the additional heating of the coffee bean beyond the second crack. When the heating rate to the onset of the first and second crack was varied, both the types and concentration of the carbonyl compounds formed during roasting were affected. Thus, heating rates of green coffee beans to the onset of the first and second cracks are important determinants of the basic taste and aroma of brewed coffee.

Coffea↗
PubMed2005

Determination of polycyclic aromatic hydrocarbons in coffee brew using solid-phase extraction.

The presence of polycyclic aromatic hydrocarbons (PAHs) in coffee has been reported and is suspected to be due to the degradation of coffee compounds during the roasting step. Due to the high toxicity of these compounds, among which benzo[a]pyrene is known to be the most carcinogenic, their presence in the coffee, especially the coffee brew that is directly ingested by the consumer, is of prime importance. However, due to the low solubility of these compounds, their concentrations are expected to be rather low. As a consequence, reliable and sensitive analytical methods are required. The aim of this study was to develop a reliable and fast analytical procedure to determine these organic micropollutants in coffee brew samples. PAHs were retained on a 0.5 g polystyrene-divinylbenzene cartridge before being eluted by a mixture of methanol/tetrahydrofuran (10:90 v/v), concentrated, and directly analyzed by reversed-phase high-performance liquid chromatography coupled to a fluorescence detector. Application to the determination of PAHs in several coffee brew samples is also given, with mean estimated concentrations in the range of 0-100 ng L(-1) for suspected benzo[b]fluoranthene and benzo[a]pyrene, whereas no fluoranthene could be detected. Tentative identification was made on the basis of UV spectra. However, identification of the suspected traces of PAHs could not be achieved due to matrix effects, so that the presence of coeluting compounds may not be excluded.

Chromatography, High Pressure Liquid↗
PubMed2006

Changes in headspace volatile concentrations of coffee brews caused by the roasting process and the brewing procedure.

Headspace-solid-phase microextraction technique (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were used to characterize the aroma compounds of coffee brews from commercial conventional and torrefacto roasted coffee prepared by filter coffeemaker and espresso machine. A total of 47 volatile compounds were identified and quantified. Principal component analysis (PCA) was applied to differentiate coffee brew samples by volatile compounds. Conventional and torrefacto roasted coffee brews were separated successfully by principal component 1 (68.5% of variance), and filter and espresso ones were separated by principal component 2 (19.5% of variance). By GC olfactometry, a total of 34 aroma compounds have been perceived at least in half of the coffee extracts and among them 28 were identified, among which octanal was identified for the first time as a contributor to coffee brew aroma.

Coffee↗
PubMed1998

Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan.

The study aims to examine the relationship between habitual coffee consumption and blood pressure. The subjects were 3336 male self-defense officials aged 48-56 years, who received a preretirement health examination at the Self-Defense Forces Fukuoka Hospital between October 1986 and December 1992. Average coffee intake in the past year was ascertained by a self-administered questionnaire. A significant inverse relation between habitual coffee consumption and blood pressure was found with and without adjustment for alcohol use, cigarette smoking, body mass index, glucose tolerance, and green tea intake. Green tea, another major source of caffeine intake in Japanese, was unrelated to blood pressure. The adjusted mean differences per cup of coffee consumed per day were -0.6 mmHg (95% confident interval [CI]: -0.9 to -0.3, p = 0.0001) in systolic blood pressure and -0.4 mmHg (95% CI: -0.5 to -0.2, p = 0.0002) in diastolic blood pressure. Habitual coffee drinkers had lower blood pressure than non-drinkers at any levels of alcohol use, cigarette smoking, obesity, and glucose intolerance. Our findings consolidate the previous observation that habitual coffee consumption was associated with lower blood pressure.

Blood Pressure↗
PubMed2000

Coffee consumption and decreased serum gamma-glutamyltransferase: a study of middle-aged Japanese men.

The potential inverse association between coffee intake and serum gamma-glutamyltransferase (GGT) was examined in a cross-sectional study involving 1353 Japanese male office workers aged 35-59 years in Osaka, Japan. Those who had serum aminotransferases exceeding the normal range and/or who had been administered medical care for, or had a past history of, liver disease were excluded. Multiple linear regression analysis and analysis of covariance were used to control for confounding variables (age, body mass index, alcohol use, and cigarette smoking) and to examine possible interactions. From the linear regression analysis, coffee intake was inversely related to serum GGT levels independently of age, body mass index, alcohol intake, and cigarette smoking. All of the latter variables were also independently and positively associated with serum GGT levels. When the interactions between coffee and each of four covariates on serum GGT were evaluated by adding each interaction term to the above regression model, significant negative interactions were observed for age and cigarette smoking. From the analysis of covariance, lower levels of serum GGT associated with coffee consumption were more evident in the older age group and at the higher levels of cigarette smoking. These findings suggest that coffee consumption is inversely related to serum GGT and that coffee may inhibit the inducing effects of aging and possibly of smoking on serum GGT in the liver.

Adult↗
PubMed2001

Effect of coffee on motor and sensory function of proximal stomach.

Some people attribute dyspeptic symptoms to drinking coffee, suggesting that coffee affects one or more functions of the proximal gastrointestinal tract. In a randomized controlled, cross-over, single-blinded study, the effects of coffee on gastric relaxation, gastric wall compliance and sensations, elicited by distension, were investigated in 10 healthy volunteers. Using the barostat technique, volume changes of an intragastric bag were recorded for 20 min after intragastric administration of 280 ml of coffee or water. Then, after deflation, the volume of the bag was increased stepwise every 3 min to assess gastric wall compliance and wall tension. At the end of every volume step, sensations (nausea, pain, and bloating) were scored. During the first 20 min after coffee administration, the volume change of the intragastric bag was larger than after water (P < 0.05). There were no differences in gastric wall compliance, wall tension, or symptom scores. In conclusions, coffee, in comparison with water, enhances the adaptive relaxation of the proximal stomach, but has no effect on its wall compliance, wall tension, or sensory function.

Adult↗
PubMed2003

Relation of coffee, green tea, and caffeine intake to gallstone disease in middle-aged Japanese men.

A possible protective effect of coffee or caffeine intake in the formation of gallstones has been suggested in some epidemiological studies. We examined the relation of coffee, green tea, and caffeine intake to gallstone disease in middle-aged Japanese men, distinguishing known gallstones from unknown diagnosed gallstones. Study subjects were 174 cases of gallstones as determined by ultrasonography, 104 cases of postcholecystectomy, and 6889 controls of normal gallbladder in the total of 7637 men who received a health examination at four hospitals of the Self-Defense Forces (SDF). Of the 174 cases of prevalent gallstones, 50 had been aware of having gallstones. Previously diagnosed gallstones and postcholecystectomy were combined as known gallstone disease. The consumption of coffee and green tea was ascertained by a self-administered questionnaire, and caffeine intake was estimated. Statistical adjustment was done for body mass index, smoking, alcohol use, rank in the SDF, and hospital. Coffee and caffeine intake were associated each with a statistically significant increase in the prevalence odds of known gallstone disease, but unrelated to newly diagnosed gallstones. Adjusted odds ratios of known gallstone disease were 1.7 (95% confidence interval [CI] 1.1-2.8) for coffee consumption of five cups or more per day vs. no consumption and 2.2 (95% CI: 1.3-3.7) for caffeine intake of 300 mg/day or more vs. less than 100 mg/day. The consumption of green-tea showed no material association with either unknown gallstones or known gallstone disease. The findings do not support a hypothesis that coffee drinking may be protective against gallstone formation.

Caffeine↗
PubMed1983

Hemodynamic and humoral effects of coffee after beta 1-selective and nonselective beta-blockade.

Several studies report a substantial rise in plasma catecholamines after caffeine. Epinephrine infusion induces a pressor response after nonselective beta-blockade. We studied the hemodynamic and humoral effects of drinking coffee after placebo and after both nonselective (propranolol) and beta 1-selective (metoprolol) blockade in 12 normotensive subjects. After placebo, coffee induced a rise in systolic and diastolic blood pressure and a fall in heart rate, whereas forearm blood flow did not change. Plasma catecholamines, especially epinephrine (+150%), rose and plasma renin activity, fell after drinking coffee. The effects of coffee on blood pressure, forearm blood flow, and all humoral parameters were not altered by pretreatment with propranolol or metoprolol. The fall in heart rate after coffee, however, seemed to be greater during propranolol. We conclude that the rise in plasma epinephrine after coffee was too small to reveal differences in reaction in propranolol- and metoprolol-pretreated subjects.

Adolescent↗
PubMed2004

Trigonelline is not responsible for the acute increase in plasma homocysteine following ingestion of instant coffee.

OBJECTIVE: To determine whether trigonelline contributes to the effect of coffee on homocysteine (Hcy). DESIGN AND INTERVENTIONS: This was a randomised crossover study. Subjects consumed 50 mg trigonelline, 5 g of instant coffee (approximately 50 mg trigonelline) or water, consumed as a single dose in 100 ml, with 1 week between each treatment. Blood samples were drawn fasting and hourly for 8 h. Urine samples were collected pretreatment and every 2 h for 8 h. SETTING: Christchurch Clinical Studies Trust, Christchurch, New Zealand. SUBJECTS: Eight healthy male subjects. RESULTS: Instant coffee raised plasma Hcy concentrations compared with water (P=0.019) and trigonelline (P=0.037). Plasma Hcy concentrations were not different between water and trigonelline treatments (P=0.789). The change in plasma Hcy concentration was higher (mean+/-s.e.) 4 h (0.7+/-0.2 micromol/l, P=0.006), 5 h (0.7+/-0.2 micromol/l, P=0.013) and 7 h (0.7+/-0.2 micromol/l, P=0.024) following coffee consumption. Urinary glycine betaine excretion was increased by coffee but not by trigonelline. CONCLUSION: Ingestion of instant coffee acutely elevated plasma Hcy; however, trigonelline is not responsible for this rise. SPONSORSHIP: Supported by the Health Research Council, the Canterbury Medical Foundation, the Foundation of Research, Science and Technology.

Adult↗
PubMed2002

Isolation and characterization of a novel Bacillus strain from coffee phyllosphere showing antifungal activity.

AIMS: The isolation and characterization of a novel coffee-associated Bacillus mojavensis strain, designated as strain AB1, and its survival on the coffee phyllosphere. METHODS AND RESULTS: A pair of 16S rDNA primers was designed to amplify a highly variable region within the 16S rDNA gene of Bacillus spp., with the purpose of identifying the AB1 isolate through PCR and sequence analysis. By this method, AB1 was identified as a strain of B. mojavensis. Bioassays were carried out to characterize the broad spectrum antifungal activity of AB1. Plant colonization studies revealed that AB1 could colonize the coffee phyllosphere better than Bacillus thuringiensis. CONCLUSIONS: These studies suggest that AB1 could be a new strain of B. mojavensis. AB1 is also shown to have antifungal activity against a wide spectrum of pathogenic fungi. The antifungal metabolite of AB1 has been partially characterized as a thermostable, protease- and alkali-resistant substance that is secreted into the surrounding medium. SIGNIFICANCE AND IMPACT OF THE STUDY: As far as is known, this is the first strain of B. mojavensis which has been identified as inhabiting the coffee phyllosphere. The study highlights the potential use of AB1 as an antifungal agent in the coffee crop and as a delivery agent of the insecticidal toxin of B. thuringiensis to the coffee phyllosphere. The 16S rRNA identification strategy discussed could also be used in the identification of other new Bacillus strains.

Animals↗