银杏叶提取物对兔血小板聚集的影响

Inhibitory effects of Ginkgo bibolia extract on platelet aggregation in rabbits

目的 探讨银杏叶提取物 (GBE)对兔血小板聚集作用的影响。方法 进行体内、体外实验观察银杏叶提取物 (GBE)对由花生四烯酸 (AA)、二磷酸腺苷 (ADP)及血小板活化因子 (PAF)诱导的兔血小板聚集作用的影响 ,并对其作用的特点进行了初步分析。结果 GBE体外选择性地抑制PAF诱导兔血小板聚集 (比浊法 )及 5 HT的释放 (荧光法 ) ,其抗血小板聚集和 5 HT释放的IC50 分别为 (4 7.5± 9.5 )mg·L-1和 (176 .3± 2 5 .5 )mg·L-1;银杏苦内酯B(BN5 2 0 2 1)体外抗聚集的IC50 为 (5 .5 6×10 -3 ± 1.0 1× 10 -3 )mg·L-1。体内试验GBE也选择性地抑制PAF诱导的兔血小板聚集 :静注GBE 5 0 ,10 0mg·kg-1的作用时间分别可持续 6 0 ,2 40min以上 ;灌胃 10 0 ,2 0 0mg·kg-1的作用持续时间分别可达 180 ,2 40min以上 ;静注和灌胃作用高峰时最大抑制率分别为 (96 .5± 6 .1) %,(83.3± 17.2 ) %。结论 GBE对由PAF ,ADP诱导的体内、体外兔血小板聚集有抑制作用 ,但对由AA诱导的聚集无影响。可见GBE是一种有效的、选择性较高的抗血小板聚集药物。

OBJECTIVE: To focus on the effects of Ginkgo bibolia extract (GBE) on platelet aggregation in rabbits. METHODS: The inhibitive rates of GBE on platelet aggregation in rabbits induced by platelet activating factor (PAF), arachidonic acid (AA) and adenosin diphosphate (ADP) in vitro, or in vivo, respectively. The anti-PAF action of GBE was analyzed. RESULTS: The results showed that in vitro GBE selectively inhibited rabbit platelet aggregation and serotonin secretion induced by PAF IC50 (47.5 ± 9.5), (176.3 ± 25.5) mg&middotL-1, respectively. Under the same experimental conditions, ginkgolide B(BN52021) induced platelet aggregation in vitro [IC50(5.56 × 10-3 ± 1.01 × 10-3) mg&middotL-1]. The platelet aggregation inhibition was also found in vivo, at 60 min, 240 min and 180 min, 240 min after administration of iv 50,100 and ig 100,200 mg&middotkg-1 of GBE, respectively. The maximum inhibitory rates were (96.5 ± 6.1) % (iv 100 mg&middotkg-1) and (83.7 ± 17.2) % (ig200 mg&middotkg-1) respectively. CONCLUSION: GBE showed inhibitory effects on the platelet aggregation induced by PAF and ADP in vivo or in vitro, but not by AA.