姜黄素在大鼠和人肝微粒体中对细胞色素P4502C8活性的影响

Effect of curcumin on the activity of cytochrome P4502C8 in rat and human liver microsomes

目的分别在大鼠和人混合肝微粒体中考察姜黄素对瑞格列奈代谢的影响,从而考察姜黄素对细胞色素P4502C8(CYP2C8)活性的影响.方法分别建立大鼠和人肝微粒体体外孵育体系,将姜黄素与瑞格列奈于37℃水浴中共同孵育,用UPLC法测定肝微粒体中瑞格列奈的剩余浓度.在系列浓度的瑞格列奈进行孵育的条件下,绘制米氏曲线,得到瑞格列奈的米氏常数(K_(m))、最大反应速率(V_(max))和固有清除率(CL_(int)).在系列浓度的姜黄素进行孵育的条件下,测定肝微粒体中瑞格列奈的减少量并计算半数抑制浓度(IC_(50)),考察姜黄素对瑞格列奈代谢的影响.结果瑞格列奈在大鼠和人肝微粒体中孵育的K_(m)值分别为(51.41±18.29)和(5.66±2.76)μmol·L^(-1),V_(max)分别为(47.29±7.81)和(1.71±0.38)μmol·min^(-1)·mg^(-1),CL_(int)分别为0.92和3.31 mL^(-1)·min^(-1)·mg^(-1).姜黄素对瑞格列奈在大鼠和人肝微粒体中均具有明显的抑制作用,IC_(50)值分别为9.87和0.31μmol·L^(-1).结论姜黄素可显著抑制瑞格列奈在大鼠和人肝微粒体中的代谢,提示两药合用时具有发生相互作用的风险,且姜黄素与其他经CYP2C8代谢的药物合用时也应谨慎.

Objective To investigate the effect of curcumin on the metabolism of repaglinide with rat and human liver microsomes,respectively,so as to study the effect of curcumin on the activity of cytochrome P4502C8(CYP2C8).Methods Curcumin and repaglinide were incubated with rat and human liver microsomal incubation system at 37℃,respectively.The residual concentration of repaglinide in liver microsomes was determined by UPLC method.With different concentrations of repaglinide,the Michaelis-Menten curve was drawn to obtain the apparent enzyme kinetics parameters of michaelis-constant(K_(m)),the maximum reaction rate(V_(max))and the intrinsic clearance(CL_(int)).With different concentrations of curcumin in microsomal incubation system,the reduction of repaglinide was determined to obtain inhibitory concentration 50(IC_(50)).Results The K_(m) values of repaglinide in rat and human liver microsomes were(51.41±18.29)and(5.66±2.76)μmol·L^(-1),respectively.The values of V_(max)were(47.29±7.81)and(1.71±0.38)μmol·min^(-1)·mg^(-1),CL_(int)were 0.92and 3.31 m L^(-1)·min^(-1)·mg^(-1).Curcumin had an inhibitory effect on repaglinide both in rat and human liver microsomes with IC_(50)values of 9.87 and 0.31μmol·L^(-1).Conclusion Curcumin can significantly inhibit the metabolism of repaglinide in rat and human liver microsomes,which suggests that there is a risk of interaction when combined.Besides,caution should also be taken when curcumin is combined with other drugs metabolized by CYP2C8.