Select Flavonoids and Whole Juice From Purple Grapes Inhibit Platelet Function and Enhance Nitric Oxide Release

Background—Moderate red wine consumption is inversely associated with coronary ischemia, and both red wine and purple grape juice (PGJ) contain flavonoids with antioxidant and antiplatelet properties believed to be protective against cardiovascular events. Acute cardiac events are also associated with decreased platelet-derived nitric oxide (NO) release. In this study, the effects of PGJ and PGJ-derived flavonoids on platelet function and platelet NO production were determined. Methods and Results—Incubation of platelets with dilute PGJ led to inhibition of aggregation, enhanced release of platelet-derived NO, and decreased superoxide production. To confirm the in vivo relevance of these findings, 20 healthy subjects consumed 7 mL · kg−1 · d−1 of PGJ for 14 days. Platelet aggregation was inhibited after PGJ supplementation, platelet-derived NO production increased from 3.5±1.2 to 6.0±1.5 pmol/108 platelets, and superoxide release decreased from 29.5±5.0 to 19.2±3.1 arbitrary units (P<0.007 and P<0.05, res...