黄芩等中药提取物对异育银鲫肝微粒体CYP1A和CYP3A的抑制作用

Inhibition of Chinese herbal extracts on CYP1A and CYP3A of liver microsomes from crucian carp(Carassius auratus gibelio)

通过肝微粒体体外孵育实验,研究黄芩、柴胡、连翘、吴茱萸和野菊花5种中药提取物对异育银鲫肝微粒体CYP450的影响。体外给药测定IC50以及相关酶动力学参数,并推测其可能的作用机制。结果显示,5种中药对7-乙氧基异吩唑酮-O-脱乙基酶(EROD)(CYP1A标志酶)的抑制程度为黄芩>连翘>野菊花>柴胡≈吴茱萸,半抑制浓度(IC50)依次为0.27,2.88,7.62,16.20和16.42 mg/mL,酶促反应动力学常数Vmax和Km为(83.33±11.32)pmol/(min.mg)和(3.05±0.89)μmol/L。据此计算黄芩、连翘、野菊花、柴胡和吴茱萸的抑制常数分别为0.16、0.39、0.61、0.40和0.59 mg/mL;黄芩、连翘和吴茱萸对红霉素-N-脱甲基酶(ERND)(CYP3A标志酶)有很弱的抑制作用,IC50分别为90.9,70.8和43.5 mg/mL。柴胡和野菊花未检测到对ERND有抑制作用。结果表明,这5种中药对CYP酶的影响因亚型不同而差别较大,对CYP1A的抑制均较显著,而对CYP3A的抑制则不明显。进一步研究它们对CYP1A的抑制机制,推测黄芩、柴胡和吴茱萸对EROD的抑制为竞争性抑制,野菊花和连翘则是反竞争性抑制。建议这5种中药与其他渔药合用时,要注意其引起其他渔药的药动学的变化,使疗效发生改变。

This study focused on the inhibition of five kinds of Chinese herbal extracts （Scutellaria, Forsythia, Bupleurum, Evodia and Chrysanthemum） on CYP1A and CYP3A of crucian carp （Carassius auratus gibelio） liver microsomes. IC50 and kinetic parameters of enzymatic reaction were determined in vitro and the inhibition mechanism was speculated. The results showed that the level of inhibition of five kinds of Chinese herb extracts on CYP1 A was Scutellaria 〉 Forsythia 〉 Chrysanthemum 〉 Bupleurum ≈ Evodia; the IC50 were 0. 27 ,2. 88 ,7. 62,16. 20 and 16.42 mg/mL, and the inhibition instants （Ki ） were 0.13, 0.38, 3.39, 1.74 and 70 mg/mL respectively. The kinetic parameters of enzymatic reaction, Vmax and Km were （83.33 ± 11.32） pmol/（min · mg） and （3.05±0.89 ） μmol/L, respectively. Scutcllaria, Forsythia and Bupleuru had a weak inhibition on CYP3A activity with the IC50 of 90. 9, 70. 8 and 43. 5 mg/mL, respectively. No inhibition was observed for Chrysanthemum and Bupleurum on CYP3A. Furthermore, it was speculated that Scutellaria, Chrysanthemum and Bupleurum were competitive inhibitors, while Evodia and Forsythia were uneompetitive inhibitors. In this study, inhibition of five Chinese herbs on the CYP450 enzymes varied greatly due to different subtypes and it showed that the inhibition on CYP1 A was significant but no significant inhibition on CYP3A. It suggested that the inhibition of CYP450 isoenzyme by herb extracts might lead to increase plasma levels and change the pharmacokinetics of drug metabolized by these isoenzymes, therefore, more care is needed when using the co-administered prescription drugs.