RESUMEN
The study of the bioavailability of active compounds in functional foods, such as polyphenol-rich beverages, is required before making nutritional claims. In this work, we aimed to study the urinary excretion of resveratrol (RV), taking into consideration its gut and microbial metabolites after consumption of a functional beverage (FB), applying a ultra performance liquid chromatography (UPLC)-MS/MS methodology. A randomized, crossover, placebo-controlled, double-blind intervention study was performed with 26 volunteers, who consumed 187 mL of a control placebo or a FB in an acute study, and twice a day during 15 days for a chronic consumption study. The whole profile of 21 RV metabolites increased after acute and chronic consumption of the FB with respect to the control-placebo beverage and to the baseline. Urinary excretion of RV and piceid phase II metabolites was similar after both consumption periods, but a later formation of microbial metabolites required urine sampling of up to 24 h after the consumption of the FB. In addition, the intervariability has been evaluated. This study allows the knowledge of the RV metabolites that reach target tissues where biological activity would be achieved in order to elucidate the beneficial effects of this grape extract FB.