Posted 01 March 2007 - 09:31 AM
I found some interesting pubmed articles about resveratrol below:
''High absorption but very low bioavailability of oral resveratrol in humans.
* Walle T,
* Hsieh F,
* DeLegge MH,
* Oatis JE Jr,
* Walle UK.
Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425, USA. wallet@musc.edu
The dietary polyphenol resveratrol has been shown to have chemopreventive activity against cardiovascular disease and a variety of cancers in model systems, but it is not clear whether the drug reaches the proposed sites of action in vivo after oral ingestion, especially in humans. In this study, we examined the absorption, bioavailability, and metabolism of 14C-resveratrol after oral and i.v. doses in six human volunteers. The absorption of a dietary relevant 25-mg oral dose was at least 70%, with peak plasma levels of resveratrol and metabolites of 491 +/- 90 ng/ml (about 2 microM) and a plasma half-life of 9.2 +/- 0.6 h. However, only trace amounts of unchanged resveratrol (<5 ng/ml) could be detected in plasma. Most of the oral dose was recovered in urine, and liquid chromatography/mass spectrometry analysis identified three metabolic pathways, i.e., sulfate and glucuronic acid conjugation of the phenolic groups and, interestingly, hydrogenation of the aliphatic double bond, the latter likely produced by the intestinal microflora. Extremely rapid sulfate conjugation by the intestine/liver appears to be the rate-limiting step in resveratrol's bioavailability. Although the systemic bioavailability of resveratrol is very low, accumulation of resveratrol in epithelial cells along the aerodigestive tract and potentially active resveratrol metabolites may still produce cancer-preventive and other effects.''
PMID: 15333514 [PubMed - indexed for MEDLINE]
''Metabolism and bioavailability of trans-resveratrol.
* Wenzel E,
* Somoza V.
German Research Center of Food Chemistry, Garching, Germany. elisabeth.wenzel@lrz.tum.de
Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a polyphenolic compound accounting to the stilbene class. Most stilbenes in plants act as antifungal phytoalexins, compounds that are usually synthesized only in response to infection or injury. Resveratrol has been detected in trees, in a few flowering plants, in peanuts, and in grapevines. The major dietary sources of resveratrol include grapes, wine, peanuts, and peanut products. Numerous in vitro studies describe different biological effects of resveratrol. The major impacts are the antioxidative, anti-inflammatory, and estrogenic effects as well as anticancer and chemopreventive activities. In order to reveal information on absorption, metabolism, and the consequent bioavailability of resveratrol, different research approaches were performed, including in vitro, ex vivo, and in vivo models, all of which are considered in this review. Summarizing the data, resveratrol is absorbed and metabolized. Around 75% of this polyphenol are excreted via feces and urine. The oral bioavailability of resveratrol is almost zero due to rapid and extensive metabolism and the consequent formation of various metabolites as resveratrol glucuronides and resveratrol sulfates. The potential biologic activity of resveratrol conjugates should be considered in future investigations.''
PMID: 15779070 [PubMed - indexed for MEDLINE]
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