黄葵总黄酮对CYP450酶的抑制作用

Inhibition of total flavonoids from Abelmoschus Manihot on cytochrome P450

研究黄葵总黄酮对人肝微粒体中细胞色素P450(CYP450)酶不同亚型的影响机制并在大鼠体内对受抑制最为显著的CYP2C9亚型进行验证。利用HPLC-MS/MS技术,通过鸡尾酒法在体外评估黄葵总黄酮对人CYP3A4、CYP2C9、CYP2C19、CYP2E1、CYP1A2和CYP2D6的抑制效应,考察其抑制机制,计算酶抑制动力学参数。在大鼠体内通过比较单次或多次给药200 mg/kg黄葵总黄酮与等剂量CMC-Na后甲苯磺丁脲的药代动力学行为差异,评估黄葵总黄酮对大鼠CYP2C11酶(CYP2C9同工酶)的影响。结果表明黄葵总黄酮对CYP2C9和CYP2E1存在显著抑制作用,IC_(50)分别为3.22和8.64μg/mL,对其他亚型也表现出一定的抑制作用,IC_(50)介于20~30μg/mL。黄葵总黄酮并非为潜在的时间依赖性抑制剂,它能竞争性抑制CYP2E1和CYP2C9,抑制常数Ki分别为3.84和6.33μg/mL,对CYP3A4介导的睾酮-6β-羟基化和咪达唑仑-4-羟基化的抑制方式为非竞争性抑制,Ki分别为7.37和3.32μg/mL,同时它也是CYP1A2、CYP2D6和CYP2C19的非竞争性抑制剂,Ki分别为8.66、11.49和21.94μg/mL。在大鼠体内,黄葵总黄酮并没有引起大鼠体内CYP2C11探针底物甲苯磺丁脲药动学行为的改变,但影响了其代谢物4-羟基甲苯磺丁脲的AUC_(0-t)、c_(max)等参数(P<0.05)。因此在临床研究中应当考察可能存在的CYP450酶介导的药物-药物相互作用。

To investigate the influential mechanism of total flavonoids from Abelmoschus Manihot(HKZ)on cytochrome P450(CYP450)isoforms in human liver microsomes and to verify its effect on the most significantly inhibited subtype CYP2C9 in rats.The inhibitory effects of HKZ on human CYP3A4,CYP2C9,CYP2C19,CYP2E1,CYP1A2 and CYP2D6 were evaluated through the cocktail method using ultra-performance liquid chromatography tandem mass spectrometry,then its inhibitory mechanism was investigated and kinetic parameters of enzyme inhibition were calculated By comparing the pharmacokinetic behaviors of tolbutamide after single or multiple administration of 200 mg/kg HKZ and equal dose of CMC-Na in rats,the effects of HKZ on CYP2C11 enzyme(CYP2C9 isoenzyme)was estimated.The results indicated the significant inhibitory effect of HKZ on CYP2C9 and CYP2E1 with IC_(50) of 3.22 and 8.64μg/mL,respectively.Also,it showed certain inhibitory ability on other isoforms with IC_(50) of 20-30μg/mL.As demonstrated,HKZ may not be a time-dependent inhibitor which competitively inhibited CYP2E1 and CYP2C9 with Ki of 3.84 and 6.33μg/mL.In contrast,it showed noncompetitive inhibition on CYP3A4 mediated testosterone-6β-hydroxylation and midazolam-4-hydroxylation reaction with Ki of 7.37 and 3.32μg/mL.It was also a noncompetitive inhibitor of CYP1A2,CYP2D6 and CYPC219 with Ki values of 8.66,11.49 and 21.94μg/mL.HKZ did not change the pharmacokinetic parameters of CYP2C11 probe substrate tolbutamide in rat,but it affected the AUC0-t,cmax of 4-hydroxytolubutamide(P<0.05).Therefore,drug-drug interaction mediated by CYP450 should be considered in clinical study.