新藤黄酸对大鼠肝微粒体细胞色素P450亚型酶活性的影响

Effects of Gambogenic Acid on Activities of Cytochrome P450 Enzymes in Rat Liver Microsomes

目的采用"Cocktail"探针药物法考察新藤黄酸对大鼠肝微粒体细胞色素P450(cytochrome P450,CYP450)亚型酶活性的影响。方法将新藤黄酸与6种亚型酶(CYP1A2、CYP2C9、CYP2C19、CYP2D6、CYP2E1、CYP3A4)对应的特异性混合探针药茶碱、双氯芬酸钠、奥美拉唑、右美沙芬、氯唑沙宗和咪达唑仑与大鼠肝微粒体孵育,采用高效液相色谱法同时检测肝微粒体中6种探针底物的相对酶活性并计算其半抑制浓度(half maximal inhibitory concentration,IC50)。结果不同浓度新藤黄酸作用后大鼠肝微粒体CYP1A2、CYP2C9、CYP2C19、CYP2D6、CYP2E1和CYP3A4酶活性相比较,差异均具有统计学意义,且随着新藤黄酸的浓度增高,各种酶的活性呈现明显的降低趋势。通过抑制曲线计算得到新藤黄酸对CYP2C19、CYP2D6、CYP3A4的IC50值分别为4.18、45.61、10.02μmol/L,对CYP1A2、CYP2C9、CYP2E1的IC50值均大于100μmol/L。结论新藤黄酸对CYP2C19酶活性有中等抑制作用,对CYP3A4酶活性有弱抑制作用,但对CYP1A2、CYP2C9、CYP2D6、CYP2E1酶活性没有抑制作用。

Objective To investigate the effects of gambogenic acid on the activities of eytochrome P450 （CYP450） enzymes in rat liver microsomes by a probe-drug cocktail. Methods The rat liver microsomes were incubated with gambogenic acid and the mixture of specific probe drugs （theophylline, diclofenac sodium, omeprazole, dextromethorphan, chlorzoxazone, and midazolam） for the six CYP450 enzymes （CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4）. High-performance liquid chromatog- raphy was applied to measure the relative enzymatic activities of six probe substrates in liver microsomes and calculate half maximal inhibitory concentration （IC^0）. Results After incubation with gambogenic acid at various concentrations, there were significant differences in the activities of CYPIA2, CYP2Cg, CYP2C19, CYP2D6, CYP2E1, and CYP3A4 in rat liver microsomes, and with the increasing concentration of gambogenie acid, the activities of these enzymes decreased significantly. According to the inhibitory curve, the IC50 of gambogenic acid for CYP2C19, CYP2D6, and CYP3A4 was 4. 180, 45.61, and 10.02 p.mo than L, respectively, and the IC50 of gambogenic acid for CYPIA2, CYP2C9, and CYP2E1 was higher 100μmol/L. Conclusion Gambogenic acid has a moderate inhibitory effect on the activity of CYP2C19 anda weak inhibitory effect on the activity of CYP3A4, but shows no inhibitory effects on CYP1A2, CYP2Cg, CYP2D6, and CYP2E1.