体外细胞色素P450同工酶对银杏叶水提取物抗血小板聚集作用的影响(英文)  

Effects of cytochrome P450 isozymes from human hepatocytes on inhibition of platelet aggregation induced by Ginkgo extract

作　　者：邱东鹰[1] 毛玉昌 乔燕荣 谭金兴 胡卓汉[2] 蔡映云[1] 

机构地区：[1]复旦大学附属中山医院老年病科,上海200032 [2]瑞德肝脏疾病研究(上海)有限公司,上海201203

出　　处：《中国临床药学杂志》2007年第3期133-138,共6页Chinese Journal of Clinical Pharmacy

摘　　要：目的应用体外肝细胞模型研究中草药银杏叶提取物的代谢途径,即细胞色素P450酶(CYP450)药物代谢酶系对银杏叶拮抗血小板聚集效应的影响。方法制备人超低温冷冻肝细胞,通过与银杏叶提取物预孵育,评估肝脏CYP450药物代谢酶系(CYP1A2、CYP286、CYP2C19、CYP2E1、CYP3A4)对银杏叶水提取物拮抗血小板活化因子(PAF)激活的血小板聚集作用。富含血小板血清(PRP)和少含血小板血清(PPP)与不同质量浓度(25、50、100、200和1000μg·L^(-1))PAF孵育,建立PAF激活血小板聚集的体外模型。银杏叶水提物与人超低温冷冻复苏肝细胞预孵育后,与PRP和PAF培养,观察银杏叶水提物的体外效应(抗PFA血小板聚集激活作用)是否受人肝细胞代谢的影响。CYP450药物代谢酶的特定抑制物伊曲康唑(CYP3A4)、α-萘黄酮(CYP1A2)、奥芬那君(CYP286)、奥美拉唑(CYP2C19)、4-甲基吡唑(CYP2E1)与人肝细胞预孵育后、与银杏叶水提物和PRP和PAF孵育,评估银杏叶水提物的体外效应与何种CYP450药物代谢同工酶有关。结果PAF激活血小板聚集作用遵循米-曼氏动力学方程,其K_m为98μ·L^(-1)。银杏叶水提物抑制PAF的血小板聚集激活作用,其半数抑制剂量为33μg·L^(-1)。人肝细胞与银杏叶水提物预孵育后,其体外效应(抗PAF血小板聚集激活作用)增强30%,差异有统计学意义(P<0.05)。人肝细胞与细胞色素CYP450同工酶CYP286、CYP2C19、CYP2E1、CYP3A4抑制剂预孵育后,银杏叶水提物的体外效应不受影响。人肝细胞与CYP1A2抑制剂预孵育后,人肝细胞对银杏叶水提物体外效应的增强作用基本消失,差异有统计学意义(P<0.05)。结论银杏叶水提物在体外能抑制PAF的血小板聚集作用,人肝细胞能显著增强这一体外效应,CYP450药物代谢酶CYP1A2可能参与银杏叶的这一体外效应的代谢活化。A/M To estimate the effects of cytochrome P450 isozymes on efficacy of Ginkgo biloba leaf extract （ GBE）-inhibition of platelet aggregation by using cryopreserved human primary hepatocytes （HPHs） in vitro. METHODS Plasma with rich platelets （PRP）, plasma with poor platelets （PPP）, and HPHs were prepared from donation. Platelet aggregation was induced by platelet activating factor （PAF） with dosing concentrations of 25,50,100,200 and 1 000μg· L^- 1. Effect of GBE on PAF induced platelet aggregation was estimated by preineubaiton of GBE before the addition of PAF. The effects of first pass metabolism on the efficacy of the GBE were investigated by preincubation of HPHs with GBE. The metabolism pathways involved for GBE were identified by preincubation of HPHs with selective inhibitors of CYP1A2 （α-naphthoflavon）, CY1P2B6 （orphenadrine hydrochlorid）, CYP2C19 （omeprazole）, CYP2E1 （4-methylpyrazole）, and CYP3A4 （itraconazole）. RESULTS PAF induced platelet aggregation followed Michaelis-Menten kinetics model with Km of 98 μg· L^- 1. GBE showed the inhibition of PAF-induced platelet aggregation with IC50 of 33 μg· L^- 1, 30% enhancement over the control. These effects of GBE were reduced significantly by selectively inhibiting CYP1A2 but CYP2B6, 2C19, 2E1 and 3A4. CONCLUSION The inhibitive effects of GBE on PAF induced platelet aggregation are regulated by CYP1A2. The study implies an application for identifying the metabolism pathway of herb medicines in vitro.

关 键 词：银杏叶提取物 血小板活化因子 血小板聚集 细胞色素P450药物代谢同工酶 

分 类 号：R285[医药卫生—中药学]