基于体内代谢特点的中药蟾酥中蟾蜍甾烯的结构与抗肿瘤活性、心脏毒性和代谢稳定性之间关系研究

Bufadienolides in Chinese medicine Chansu with the specific structures had the significant anticancer activities, and cardiocytoxicities as side effects, meantime their metabolism stabilities were very poor.Their anticancer bioactivities were more potent than taxol.So it is very important and necessary to elucidate their relateships of chemcial structures with the anticancer, cardiocytoxicities and metabolism stabilities. Based on our preliminary researches, we intend to investigate the anticancer, cardiocytoxicities and metabolism stabilities of bufadienolides, according to their metabolic characteristics in vivo. By the metabolism methods and the combined biotransformation simulation, the in vivo metabolites of major bufadienolides in chansu would be isolated and identified exactly by phytochemical methods, which would clarify the metabolic reaction types and metabolic pathways of bufadienolides. And then, the studies of metabolism stabilities were carried out to obtain the key informations such as drug metabolism enzyme and kinetic parameters by using these in vivo metabolites purified. According to these data mentioned above, we could summarize the qualitative and quantitative relationships of bufadienolides between the metabolism stabilities and molecular structures by the computational chemistry and molecular docking methods. Meanwhile, the anticancer bioactivities and cardiocytoxicities of bufadienolides and their metabolites would be evaluated by using the modern pharmacology approaches. All of these results would indicate the key structural domains of bufadienolides in the anticancer, cardiocytoxicities and metabolism stabilities, and reveal the real substance of bufadienolides in Chansu with the potent activities, low toxicity and excellent metabolism stability, and then provide the theory and research foundations for developing the novel antitumor leading compounds from Chinese medicine Chansu.

中药蟾酥中含量丰富的蟾蜍甾烯类成分具有显著的抗肿瘤活性和一定心脏毒性，体内代谢研究表明该类成分代谢稳定性差，可生成大量体内代谢产物。因此诠释蟾蜍甾烯及其体内代谢产物的结构与活性、毒性、代谢稳定性的关系就显得十分必要。结合前期研究基础，本项目拟开展蟾蜍甾烯类成分的抗肿瘤活性、心脏毒性和代谢稳定性研究。通过组合微生物转化和活体胆汁富集等手段，分离鉴定蟾蜍甾烯类的体内代谢产物，阐明其代谢通路。利用获取的体内代谢产物开展代谢稳定性研究，测定代谢酶亚型和酶促代谢动力学等关键信息，再结合计算化学和分子对接手段，揭示该类成分的代谢稳定性与分子结构之间的定性和定量关系。同时，利用药理学和计算化学手段，阐明蟾蜍甾烯及其代谢产物的结构与活性、毒性的关系。综合上述信息，揭示蟾蜍甾烯类成分活性、毒性、代谢稳定性的关键结构域，为从中药蟾酥中发现活性好、毒性低、代谢稳定性佳的蟾蜍甾烯类抗肿瘤先导化合物奠定基础。

蟾酥为传统中药，其主要成分为蟾蜍甾烯类化合物(华蟾毒精、脂蟾毒配基、蟾毒灵等成分)，具有显著的抗肿瘤作用，同时也表现出显著毒性。前期研究报道主要集中在整体药物代谢动力学的水平上，并未深入揭示化学结构、代谢属性以及生物活性之间的关系。因此，本项目重点研究中药蟾酥中系列化学成分的代谢属性和稳定性(代谢产物鉴定、代谢酶归属与代谢动力学、代谢种属差异等)，代谢对活性与毒性的影响，系统揭示中药蟾酥中代谢稳定性优良、高效低毒的关键药效物质基础。通过系统研究我们成功揭示了中药蟾酥各主要成分的人体代谢属性，发现其主要由代谢酶CYP3A4、UGT2B7以及SULT2A1参与代谢，并且以CYP3A4代谢为主，代谢位点为1,5位。并发现了一个结构新颖的CYP3A4酶高选择性探针BF；同时还从中药蟾酥中发现了首个UGT1A3/1A4的双功能探针DCB，总结出蟾蜍甾烯类成分的结构与代谢属性之间的定量构效关系和结构预测模型。通过系统的药效学筛选，并结合代谢属性的优化，发现出中药蟾酥的主要活性形式之一(CS-6)，该化合物表现出良好的代谢属性和优良的活性，具有较好的开发价值。我们的有利指导了中药蟾酥的开发与临床的合理使用。相关研究发表通讯作者SCI论文22篇，其中包括Chemical Communications.; Scientific Reports.; Oncotarget; Biochemical Pharmacology.; AAPS Journal.；Int. J. Nanomed.; Drug Metabolism and Disposition.; RSC Advances.; J. Nat. Prod. Journal of Lipid Research.等，IF>5的文章 6篇，其中两篇文章入选ESI高被引论文。