Effect of a micronized purified flavonoid fraction on in vivo platelet functions in the rat

The aim of this study was to investigate the effects of a micronized purifi ed flavonoid fraction (MPFF) on in vivo rat platelet functions. Platelet ag gregation and disaggregation were evaluated by a noninvasive, automated iso tope monitoring system (AimsPlus). Indium-labeled platelets were injected i nto anesthetized rats and stimulated by adenosine diphosphate (ADP) (10 mu g/kg, i.v.) or collagen (50 mu g/kg, i.v.). Fibrinogen binding to ex vivo A DP-activated platelets was determined by flow cytometry, MPFF (100 mg/kg, p .o.) significantly reduced ADP-induced platelet aggregation (p<0.05) and in creased platelet disaggregation (p<0.05) compared with controls. Moreover, MPFF inhibited collagen-induced platelet aggregation (p<0.001) and increase d platelet disaggregation (p<0.01). In addition, fibrinogen binding to 2.5 or 5 mu M ADP-stimulated platelets also was reduced significantly (p<0.05 a nd 0.01, respectively). These results show that MPFF inhibits in vivo rat p latelet functions. (C) 1999 Elsevier Science Ltd. All rights reserved.