甘草素在体外不同种属肝微粒体中的代谢差异研究

In vitro metabolism of liquiritigenin in liver microsomes of different species

目的对甘草苷的苷元甘草素在体外不同种属肝微粒体中的代谢差异进行比较研究,为甘草苷的进一步研究开发提供参考依据。方法甘草素与不同种属,包括大鼠、小鼠、人、犬及猴的肝微粒体进行孵育,比较其代谢稳定性和代谢转化情况。代谢稳定性通过底物消除法分析甘草素的剩余底物浓度水平随时间的变化,计算体外消除半衰期(t1/2)。进一步对甘草素在肝微粒体孵育后生成的代谢产物谱以及代谢途径进行分析。结果在I相肝微粒体孵育体系中,甘草素在5个种属肝微粒体中发生代谢的t1/2依次为大鼠<小鼠<人<猴<犬;在II相肝微粒体孵育体系中,甘草素代谢都非常快,除小鼠外,均在5 min内下降50%以上。甘草素与人肝微粒体进行II相孵育产生的代谢产物谱和猴的相同,其余种属则与人有明显不同。结论甘草素在猴肝微粒体中的代谢稳定性和代谢产物谱均与人最相似,其次为犬肝微粒体,大鼠和小鼠则与人存在明显差异。在进一步的临床前药代和毒理研究中可选用猴或犬作为模型动物。

Objective To compare in vitro metabolic differences of liquiritigenin, an aglycone ofliquiritin, among liver microsomes of different species, which would provide reference for fiarther research and development ofliquiritin. Methods Metabolic stability and metabolic biotransformation were investigated after liquiritigenin was incubated with rat, mouse, human, dog, and monkey liver microsomes. Metabolic stability was evaluated using a substrate depletion approach, and the results were reported as ＂% liquiritigenin remaining＂, which was then used to calculate the in vitro half-life （t1/2）. Metabolic biotransformation was characterized by metabolite profiling. Results In liver microsomal incubation systems of five species, the tl/2 values of liquiritigenin for phase I were as follows： rat 〈 mouse 〈 human 〈 monkey 〈 dog, whereas for phase II, the metabolic rates were all fast and the remaining of liquiritigenin were all below 50% in 5 min except mouse. In addition, phase II metabolite profiling in monkey liver microsomes was identical to that of human, but marked differences were found between other species and human. Conclusion The metabolic characteristics of liquiritigenin in monkey liver microsomes is most similar to that of human, then followed by dog, and marked differences existed between rat, mouse and human. Therefore, monkey or dog could be the animal model for further preclinical pharmacokinetic and toxicological studies.