基于代谢活化的龙胆等中药中环烯醚萜类成分的利胆药效物质基础研究

Cholestasis is a symptom of clinical hepatic diseases and with high incidence in China. As so far, due to the complexity of the etiology and pathogenesis, there is little effectively therapeutic drug in clinical application, only ursodesoxycholic acid and other several agents show the limited improved effect. The treatment of cholestasis by traditional Chinese medicine (TCM) has a long period. The Chinese herbal medicines with cholagogic activity, such as Gentiana scabra and Gardenia jasminoides are usually used in clinic. Iridoids have revealed significant choleretic activities, which are believed to be active components of the above-mentioned medicinal herbs. However, due to the unstability of their structures and low activity in vitro, structure-activity relationship and therapeutic mechanisms of iridoids are still unclear. Our previous research indicated that gentiopicroside, a representative iridoid in Gentiana scabra, could undergo in vivo metabolism to generate reactive molecules capable of processing its bio-activity. The results suggested that iridoids from herbs may have to experience in vivo metabolic activation to form chemically reactive metabolites. Therefore, based on the metabolic activation, iridoid compounds from Gentiana scabra, Gardenia jasminoides, Swertia bimaculata, Swertia mileensis and Picrorhiza scrophulariiflora will be selected in this project. Through the identification of in vivo reactive metabolites and cholagogic activity evaluation, the effective material foundation of iridoids, as well as the related therapeutic mechanism will be elucidated. The above research will provide a new idea for investigating traditional cholagogic herbs with modern theory.

胆汁淤积是临床肝病的一组综合症，在我国发病率较高，但由于病因病机复杂，目前临床仅有熊去氧胆酸等少数药物可进行改善性治疗。中医药治疗胆汁淤积的历史悠久，临床上使用的多为清热利胆类药物，如龙胆、栀子等。上述清热利胆类中药的主要活性成分为环烯醚萜类化合物，但由于该类成分结构不稳定、分子生物水平活性低，其体内构效关系、作用机理尚不明确。前期工作发现龙胆中的龙胆苦苷被动物口服摄入后，可经过有机体的代谢，转化为活性代谢产物，进而发挥药效。这提示环烯醚萜类成分进入体内后，可能存在着“代谢活化”的过程。鉴于此，本项目以清热利胆中药龙胆、栀子、獐芽菜、青叶胆和胡黄连等为主要对象，着眼其含有的共性活性成分－环烯醚萜类化合物，以体内代谢活化为主要切入点，通过其体内药效结构的辨识和利胆活性的评价，揭示环烯醚萜类化合物治疗胆汁淤积的药效物质基础及生物效应机理，同时为清热利胆类中药用现代理论阐释提供一个新的思路。

中药药效物质基础的阐明是现代中药发展的基础及核心问题。本项目探索性的以清热利胆类中药龙胆、青叶胆、栀子、胡黄连为主要对象，针对其一大类共性成分－环烯醚萜苷类化合物，通过阐明体内代谢途径及评价代谢产物活性，辨识其在体内发挥活性作用的“药效团”结构。.本项目首先采用分析化学和药物代谢学等方法对龙胆苦苷等具有代表性的环烯醚萜苷类成分龙胆苦苷、当药苷、京尼平苷和胡黄连苦苷II的大鼠体内代谢途径进行了表征。对灌胃给药后大鼠的血清、尿液、胆汁和粪便进行了代谢产物的寻识，并应用高分辨数据和多级碎片信息对代谢产物的结构进行了鉴定。同时，还对各化合物在活体大鼠肠道内的转化过程开展了研究。本项目还运用系统分离化学技术对生物样本中的环烯醚萜苷类化合物在体内的主要代谢产物进行分离、纯化，并借助蛋白酶水解、肠道菌转化等体外方法对环烯醚萜苷类化合物的潜在活性产物进行量产制备。共检测并鉴定50个代谢产物，分离得到7个代替代谢产物，并进行了活性评价。.通过本项目的开展，逐步明确了环烯醚萜苷类成分的体内过程，并根据研究结果推断其体内药效团结构为化合物苷元部分，阐明了其保肝利胆作用的物质基础，为中药药效物质基础的研究提供了一个新模式。