没食子酸对大鼠谷胱甘肽硫转移酶的影响及其作用机制  

Study on the effects and its mechanism of gallic acid on GST in rat

作　　者：张有金[1] 杨德华[1] 邢莎莎[1] 雷霞[1] 

机构地区：[1]成都大学附属医院药物临床试验中心,四川成都610081

出　　处：《华西药学杂志》2017年第6期592-594,共3页West China Journal of Pharmaceutical Sciences

摘　　要：目的研究没食子酸对谷胱甘肽硫转移酶(GST)的影响及其作用机制。方法测定没食子酸对GST的半数抑制浓度(IC50),考察没食子酸对GST体外活性的影响;通过没食子酸与GST的时间依赖性实验来判断其抑制机制;用没食子酸与GST超速离心和加入10 Km1-氯-2,4-二硝基苯(CDNB)实验来确认抑制机制;通过抑制动力学研究来考察抑制模型及强度。采用Western-Blot法测定各组大鼠肝、肾、肠中m GST-1蛋白的表达,考察没食子酸对GST蛋白表达的影响。结果在体外,没食子酸对GST有明显的抑制作用,其IC50=14.79μmol·L^(-1);经超速离心后,GST酶活性从11.81%±3.62%恢复到71.83%±2.87%,加入10 K_m的CDNB后,酶活性从39.74%±6.17%恢复到89.17±3.26%,表明没食子酸对GST是可逆性抑制,属中等强度(K_i=9.49μmol·L^(-1))的混合型抑制;没食子酸可显著增加肝、肾、肠中GST蛋白的表达。结论在体外,没食子酸是GST的中等强度的混合型抑制剂;在体内,没食子酸能明显增强GST蛋白的表达。没食子酸代偿性诱导GST蛋白的表达且作用强于对其活性的抑制。OBJECTIVE To study the effects of gallic acid on GST and its mechanism. METHODS The inhibition IC50 of gallic acid on the activity of GST was determined to study the effect of gallic acid on GST activity in vitro. Gallic acid and GST were carried on the time -dependenee preliminary to judge its inhibitory mechanism. The ultracentrifugation and adding 10 Km of CDNB respectively for gallic acid were conducted to determine the inhibitory mechanism. The inhibition kinetic studies for gallic acid was done to determine the inhibitory strength. The mGST - 1 protein expression in liver, kidney and intestinal of the drug group and the control group were determined in rat by Western - Blot method to investigate the effect of gallic acid on the expression of GST protein. RESULTS In vitro,there was obvious inhibitory effect on GST by the gallic acid （ ICs0 = 14.79μmol·L-1）. There was no time - dependence for the inhibition of gallic acid on GST. The enzyme activity was from 11.81% ±3.62% to 71.83% ±2.87% by ultracentrifngation and from 39.74% ± 6.17% to 89.17% ± 3.26% after adding 10 Km CDNB, which showed that gallic acid on GST was reversible inhibition. In the inhibition kinetics study, the mixed type of reversible moderate intensity inhibition was found（ Ki = 9.49μmol·L-1）. In vivo, gallic： acid could remarkably increase the GST protein expression of the liver, kidney and intestinal in rats. CONCLUSION In vitro, gallic acid is GST mixed type reversible inhibitior. However, the protein expression of GST was induced by gallic acid in vivo. Gallic acid ean eompensatorily induce the GST protein expression,and this effect is stronger than the inhibition of gallic acid on the GST activity.

关 键 词：没食子酸 谷胱甘肽转移酶 大鼠肝微粒体 体外 抑制 谷胱甘肽硫转移酶蛋白 作用机制 蛋白表达 

分 类 号：R96[医药卫生—药理学]