Pharmacokinetic study of trans-resveratrol in adult pigs.

A number of pharmacokinetic studies have shown marked differences in the plasma metabolic profile of resveratrol (RES) between humans and animals and between individuals of the same species, which complicates the identification of the putative bioactive metabolites responsible for the beneficial effects of RES. On the basis of the physiological similarity between pigs and humans, the aim of this work was to characterize the metabolic profile and pharmacokinetics of RES in the plasma of pigs and to compare this to values reported in humans. RES (5.9 mg/kg of body weight) was orally administered to pigs. The following metabolites were identified in plasma using HPLC-MS/MS: RES-diglucuronide (1), two isomers of RES-sulfoglucuronide (2, 3), two isomers of RES-glucuronide (4, 5), RES-sulfate (6), and RES. The most abundant metabolites were 2, 5 (identified as resveratrol 3-O-glucuronide), and 6. The t(max) ranged from 0.9 h for compounds 2 and 5 to 2 h for compound 3. The highest C(max) value was 2223 ng/mL (5.5 μM) for metabolite 5, which was 2.6-, 3.3-, and 12-fold higher than that for metabolites 6, 2, and 3, respectively. Peak plasma levels of RES (53 ng/mL; 0.23 μM) were detected 0.5 h after RES ingestion. Apart from the low levels of RES aglycone, the RES metabolic profile in pigs differs from that found in humans. The identification of the actual active RES metabolites is a challenge that requires more complex studies which should take into account many possible influencing factors such as age, gender, and methodological approaches.