Effect of flavonoids on thrombin-, PAR1-AP- and PAR4-AP-induced [Ca2+]i mobilization. Oregon Green BAPTA-1 AM-loaded platelets were incubated with dimethylsulphoxide as control, flavonoids (50 µM), the PI3K inhibitor LY294002 (50 µM) or the phospholipase C inhibitor U73122 (10 µM) and stimulated with 0.2 U·mL−1 thrombin, 25 µM PAR1-AP or 150 µM PAR4-AP. Data (n= 4) represent mean percentage of peak calcium mobilization (values obtained in stimulated control samples = 100%). *P < 0.05 versus control activated samples. NA, non-activated; API, apigenin; GEN, genistein; QUE, quercetin; RUT, rutin; LY, LY294002.