16 June 2015 In Phenolic compounds

In humans, urinary hydroxytyrosol (OHTyr) concentrations have been associated to alcohol and wine consumption. To explore the role of wine components on promoting an endogenous OHTyr generation we performed a cross-over, double-blind, randomized controlled clinical trial (n = 28 healthy volunteers). Ethanol (wine and vodka), dealcoholized wine, and placebo were administered. Alcohol, dealcoholized wine, and particularly wine promoted a de novo OHTyr generation in vivo in humans. Potential OHTyr precursors (tyrosine, tyrosol, tyramine) were investigated in rats. Tyrosol was metabolized to OHTyr. Collating both studies, it is postulated that an increased Tyr bioavailability, a shift to a reductive pathway in dopamine and tyramine oxidative metabolism, and the biotransformation of Tyr to OHTyr were mechanisms involved in the OHTyr endogenous generation.

15 June 2015 In Phenolic compounds

SCOPE: Grape seed polyphenol extract (GSPE) is receiving increasing attention for its potential preventative and therapeutic roles in Alzheimer's disease (AD) and other age-related neurodegenerative disorders. The intestinal microbiota is known to actively convert many dietary polyphenols, including GSPE, to phenolic acids. There is limited information on the bioavailability and bioactivity of GSPE-derived phenolic acid in the brain.

METHODS AND RESULTS: We orally administered GSPE to rats and investigated the bioavailability of 12 phenolic acids known to be generated by microbiota metabolism of anthocyanidins. GSPE treatment significantly increased the content of two of the phenolic acids in the brain: 3-hydroxybenzoic acid and 3-(3 -hydroxyphenyl)propionic acid, resulting in the brain accumulations of the two phenolic acids at micromolar concentrations. We also provided evidence that 3-hydroxybenzoic acid and 3-(3 -hydroxyphenyl)propionic acid potently interfere with the assembly of beta-amyloid peptides into neurotoxic beta-amyloid aggregates that play key roles in AD pathogenesis.

CONCLUSION: Our observation suggests important contribution of the intestinal microbiota to the protective activities of GSPE (as well as other polyphenol preparations) in AD. Outcomes from our studies support future preclinical and clinical investigations exploring the potential contributions of the intestinal microbiota in protecting against the onset/progression of AD and other neurodegenerative conditions.

06 May 2014 In Phenolic compounds




AIMS: The present study analyzed the association between weekend ethanol and high-sucrose diet on oxygen consumption, lipid profile, oxidative stress and hepatic energy metabolism. Because resveratrol (RS, 3,5,4'-trans-trihydroxystilbene) has been implicated as a modulator of alcohol-independent cardiovascular protection attributed to red wine, we also determined whether RS could change the damage done by this lifestyle.

METHODS: Male Wistar 24 rats receiving standard chow were divided into four groups (n = 6/group): (C) water throughout the experimental period; (E) 30% ethanol 3 days/week, water 4 days/week; (ES) a mixture of 30% ethanol and 30% sucrose 3 days/week, drinking 30% sucrose 4 days/week; (ESR) 30% ethanol and 30% sucrose containing 6 mg/l RS 3 days/week, drinking 30% sucrose 4 days/week.

RESULTS: After 70 days the body weight was highest in ESR rats. E rats had higher energy expenditure (resting metabolic rate), oxygen consumption (VO(2)), fat oxidation, serum triacylglycerol (TG) and very low-density lipoprotein (VLDL) than C. ES rats normalized calorimetric parameters and enhanced carbohydrate oxidation. ESR ameliorated calorimetric parameters, reduced TG, VLDL and lipid hydroperoxide/total antioxidant substances, as well enhanced high-density lipoprotein (HDL) and HDL/TG ratio. Hepatic hydroxyacyl coenzyme-A dehydrogenase (OHADH)/citrate synthase ratio was lower in E and ES rats than in C. OHADH was highest in ESR rats.

CONCLUSIONS: The present study brought new insights on weekend alcohol consumption, demonstrating for the first time, that this pattern of ethanol exposure induced dyslipidemic profile, calorimetric and hepatic metabolic changes which resemble that of the alcoholism. No synergistic effects were found with weekend ethanol and high-sucrose intake. RS was advantageous in weekend drinking and high-sucrose intake condition ameliorating hepatic metabolism and improving risk factors for cardiovascular damage.




06 May 2014 In Phenolic compounds

Resveratrol, which may occur in wine, was suggested to act as a chemopreventive agent against the carcinogenic effects of ethanol. The assumption was based on data from experimental animals, which have shown that resveratrol above certain thresholds may reduce the incidence of tumours in several of the alcohol-related cancer sites (colon, liver and female breast). Using a probabilistic Monte Carlo type methodology, we estimated daily intake based on chemical analysis of resveratrol (n = 672) and ethanol (n = 867). Benchmark dose (BMD)-response modelling was conducted for resveratrol based on eight animal experiments, whereas BMD data for ethanol were taken from the literature. The margin of exposure (MOE) was calculated for both substances as an indicator if the intake may reach effective dosages. For intake of one 100-mL glass of wine, the average MOE was found to be 4.1 for ethanol and 459,937 for resveratrol. In the best-case scenario for resveratrol (e.g., very high contents and assuming a low effective dosage), the minimum MOE would be 111, which means that 111 glasses of wine need to be consumed daily to reach the BMD. The MOE ratio between resveratrol and ethanol is 166,128 on average, meaning that per glass of wine, ethanol is more than 100,000 times more potent than resveratrol. As resveratrol intake may not optimally reach the effective dosage, our study excludes a preventive effect of this substance on alcohol-related cancer. Commercial information about cancer-preventive or -protective effects of resveratrol in wine is misleading and must be prohibited.

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