High absorption but very low bioavailability of oral resveratrol in humans

Walle T, Hsieh F, DeLegge MH, Oatis JE Jr, Walle UK · Drug Metabolism and Disposition

The bioavailability paper the whole oral-resveratrol question turns on: absorption was at least 70%, but free unchanged resveratrol in plasma was only trace-level (<5 ng/ml) because of extremely rapid sulfate and glucuronide conjugation in the intestine and liver. Whatever resveratrol does in a dish of chondrocytes, almost none of the free compound is circulating after a swallowed dose.

Population

Six healthy volunteers given 14C-labelled resveratrol orally and intravenously

Intervention

25 mg oral 14C-resveratrol (dietary-relevant dose); radiolabel tracking of absorption, metabolism and excretion

Limitations

Six subjects, single 25 mg dose; whether conjugated metabolites retain activity or regenerate free resveratrol in tissue remains unresolved. Descriptive pharmacokinetics, no clinical endpoint.