EFFECT OF QUERCETIN ON PLATELET-AGGREGATION INDUCED BY OXYRADICALS

AIM: To study the action of quercetin (Que) on inhibiting platelet agg regation. METHODS: Active oxygen free radicals produced by xanthine/xa nthine oxidase (Xan/XO) reaction was used, platelet aggregation was de termined by the turbidimetric method, and the Xan/XO oxyradicals gener ating reaction by luminol-dependent chemiluminescence (Che) method. RE SULTS: Active oxygen free radicals enhanced the platelet aggregation i nduced by ADP 1.6 mu mol . L(-1). The rate of maximal aggregation incr eased from 29%-38% for ADP to 59%-70% for ADP+Xan/XO. The enhancement was abolished by the treatment of platelet-rich plasma (PRP) with Que 650 mu mol . L(-1) or hydrocortisone (Hyd) 900 mg . L(-1). Both Que an d Hyd scavenged the active oxyradicals in vitro. The Che was decreased by 75.7% (Que 4 mu mol . L(-1)) and 79.0% (Hyd 900 mg . L(-1)) as com pared with control. CONCLUSION: Active oxygen free radicals participat ed in the platelet aggregation, and scavenging oxyradicals by Que was one of mechanisms of inhibiting platelet aggregation.