人尿苷二磷酸葡糖醛酸转移酶(UGT)亚型参与反式-白藜芦醇体外代谢的研究

Study on human UDP-Glucuronosyltransferase(UGT) isoforms involved in in vitro metabolism of trans-resveratrol

目的:研究参与反式-白藜芦醇(trans-resveratrol,TR)Ⅱ相代谢的主要尿苷二磷酸葡糖醛酸转移酶(UGTs)亚型。方法:在体外对反式-白藜芦醇与12种主要的人重组UGT亚型进行温孵,采用液相色谱-质谱法测定其葡萄糖醛酸代谢产物,对其结构做初步分析,并考察不同UGT亚型对白藜芦醇代谢产物生成速率的影响。结果:在体外代谢系统中,白藜芦醇被UGT催化生成2种单葡萄糖醛酸代谢产物M-1和M-2,初步推断其为白藜芦醇-4'和3-葡萄糖醛酸化物,亚型UGT1A1,1A3,1A8,1A9,1A10都参与了催化产生代谢产物M-1和M-2,UGT1A6,1A7仅对M-2的生成有贡献。随着底物浓度的升高,UGT1A1,1A10催化底物产生M-1和M-2及1A8催化底物产生M-2的速率都减慢,出现了底物抑制现象。结论:UGT1A1,1A8,1A9,1A10参与了代谢产物M-1的产生,其中UGT1A9的贡献最大,UGT1A1,1A6,1A7,1A8,1A9,1A10参与了代谢产物M-2的产生,其中1A1和1A9贡献最大,UGT1A3也有少量参与2种代谢物的产生,其他亚型几乎都不参与反式-白藜芦醇的Ⅱ相代谢反应。

Objective:To study major human UGT isoforms involved in trans-resveratrol(TR) phase II metabolism.Method:trans-resveratrol and 12 major human UGT isoforms were incubated in vitro and then glucuronic acid metabolites were determined by HPLC-MS,in order to preliminarily analyze the structure and observe the effect of different UGT isoforms on the generation rate of glucuronic acid metabolites.Result:In in vitro metabolic system,two metabolites-4'-O-monoglucuronide resveratrol(M-1) and 3-O-monoglucuronide resveratrol(M-2)-were generated from trans-resveratrol after being catalyzed by UGT.During the cause,generation of M-1 and M-2 were catalyzed by UGT1A1,UGT1A3,1A8,1A9 and1A10,whereas only UGT1A6 and 1A7 contributed to the formation of M-2.Both the formation rate of M-1 and M-2 catalyzed by UGT1A1,1A10 and the formation of M-2 catalyzed by UGT1A8 slowed down with the increasing concentration of substrates,causing the phenomenon of 'substrate inhibition'.Conclusion:UGT1A1,1A8,1A9,1A10 get involved in the formation of M-1,and of them UGT1A9 is the most important contributor.UGT1A3 also makes small contribution to the formation of M-1 and M-2,while other UGT isoforms show hardly any reaction with the trans-resveratrol phase II metabolites.