Low concentrations of resveratrol potentiate the antiplatelet effect of prostaglandins.

Resveratrol, a polyphenolic compound found in grapes and other fruits, is thought to contribute to the cardioprotective effect of red wine. While resveratrol exhibits some antiplatelet effect in vitro, the concentrations needed are much higher than those in plasma after consumption of red wine. In the present study, we investigate if resveratrol is able to potentiate the effect of endogenous antiplatelet substances--prostaglandin (PG) I2 and PGE1. In human platelet suspension resveratrol at relatively low concentrations (2 or 5 microM), which did not affect platelet function, significantly enhanced the inhibitory activity of PGs on platelet aggregation caused by collagen. The mechanisms underlying this effect may be associated with the inhibition of protein kinase C activation and protein tyrosine phosphorylation, but not with cyclic nucleotide levels and intracellular calcium mobilization in platelets. Our results might provide a possible explanation for the in vivo antiplatelet effect of resveratrol despite the poor bioavailability and the weak in vitro activity.