Figure 2.

The extent of inhibition of platelet function by flavonoids and metabolites correlate with their potencies. Washed human platelets (4 × 10⁸ cells·mL⁻¹) loaded with [³H]-5-HT were pretreated with increasing concentrations of flavonoids [quercetin (Q): A.i, A.ii and A.iii, apigenin: B.i, B.ii and B.iii and catechin: C.i, C.ii and C.iii], metabolites (tamarixetin (T) and quercetin-3′-sulphate (Q-3′-S): A.i, A.ii and A.iii) or solvent control [DMSO (0.2% v/v)] for 5 min. Platelets were then stimulated with collagen (5 µg·mL⁻¹) for 90 s and aggregation and 5-HT secretion were measured as a percentage of the DMSO-treated, collagen-stimulated control values (100%). The data points represent the mean (n= 3) aggregation or 5-HT secretion for each treatment (±SEM). *P≤ 0.05, **P≤ 0.01 and ***P≤ 0.001 compared with the control (DMSO-treated, collagen-stimulated platelets).