五种中药提取物对拟穴青蟹肝微粒体CYP1A的抑制作用

Inhibition of five Chinese herbal extracts on CYP1A of hepatopancreas microsome in Scylla paramamosain

利用肝微粒体体外孵育体系,通过酶促反应动力学研究黄芩、柴胡、连翘、吴茱萸和野菊花5种中药提取物对拟穴青蟹(Scylla paramamosain)肝微粒体CYP1A的抑制作用。方法:5种中草药提取物分别与拟穴青蟹肝微粒体共同孵育,荧光分光光度法测定探针药物7-乙氧基异吩唑酮代谢产物试卤灵的生成量,来反映中药提取物对CYP1A活性的影响,计算酶促反应动力学常数Vmax和Km,推算表示抑制程度的IC50。结果:5种中草药提取物对EROD的抑制程度为黄芩>野菊花>连翘>柴胡>吴茱萸,IC50依次为0.46、0.80、1.07、3.99和17.79 mg/mL,其中,黄芩、柴胡和吴茱萸对EROD的抑制为竞争性抑制,野菊花则是反竞争性抑制,而连翘的抑制类型则是混合型。酶促反应动力学常数Vmax和Km为31.25 pmol/(min.mg)和1.02μM。黄芩、柴胡、连翘、吴茱萸和野菊花的抑制常数分别为0.13、0.38、3.39、1.74和70 mg/mL。结论:5种中药提取物对拟穴青蟹CYP1A均有不同程度的抑制作用,当它们与一些化学药物作为处方药搭配使用时可能产生药物相互作用,引起药效的改变。

The inhibition of five kinds of Chinese herbal extracts（Scutellaria,Forsythia,Evodia,Chrysanthemum and Bupleurum） on the mud crab（Scylla paramamosain） liver microsomal CYP1A was studied.Methods： The in vitro experiments were performed with hepatopancreas microsomal incubation system： in order to simulate CPY1A enzymatic activity,CYP1A-related ethoxyresorufin-O-deethylase（EROD） was assayed with the hepatopancreas microsomes of the mud crab,and the reaction product resorufin in the supernate was measured fluorometrically;Subsequently,the type of inhibition and the kinetic constants（Vmax and Km） were determined through the study of enzymatic kinetics;Finally,the IC50 were determined by performing the in vitro inhibition tests.Results： the level of inhibition of five kinds of Chinese herbal extracts on CYP1A was Scutellaria Forsythia Evodia Chrysanthemum Bupleurum;the IC50 were 0.46,0.80,1.07,3.99 and 17.79 mg/mL;The types of inhibition of these herbal extracts on CYP1A were quite different： utellaria and Bupleurum were competitive inhibitors,and chrysanthemum indicum was uncompetitive inhibitor,but the inhibition type of Weeping Forsythia was mixed.Vmax and Km were 31.25 pmol/（min·mg） and 1.02 uM respectively.The Ki of Scutellaria,Bupleurum,Forsythia,Weeping Forsythia,Evodia and chrysanthemum indicum extacts were 0.13、0.38、3.39、1.74 and 70 mg/mL respectively.It suggested that these five kinds of Chinese herbal extracts might be the inhibitors to the mud crab CYP1A.Therefore,more care is needed when the co-administered prescription drugs were used given that these herbs can change the pharmacokinetics of medicine metabolized by CYP1A.