蝙蝠葛碱的代谢活化和肺毒性机理研究

With the globalization of traditional Chinese medicine (TCM), safety of TCM use and evaluation of toxic TCM as well as toxic components of TCM are in urgent need. Bei-Dou-Gen (dauricum), a common TCM, is listed as a toxic TCM in Chinese Pharmacopeia, but both the substance basis of the toxic TCM and the mechanism of toxic action of the TCM remain unknown. Recently, our group reported that dauricine, a major component of Bei-Dou-Gen, induced pulmonary toxicity and apoptosis in animals. In addition, we found that dauricine was metabolized to an electrophilic reactive metabolite catalyzed by cytochrome P450 and that the formation of the reactive metabolite was associated with the pulmonary toxicity induced by Bei-Dou-Gen. As a continuous work, we will 1) investigate pulmonary protein covalent binding derived from reactive metabolites of Bei-Dou-Gen; 2) identify the critic adducted proteins associated with dauricine-induced lung toxicity; 3) verify the role of P450 3A5 in pulmonary toxicity of dauricine; and 4) determine the structure-activity (toxicity) relationships of dauricine. This application combines multi-disciplines which allows us to elucidate the molecular mechanisms of dauricine toxicity and to provide scientific foundation for the identification of substance basis of toxic TCM Bei-Dou-Gen and for clinic treatment of Bei-Dou-Gen poisoning.

随着中药的全球化，保证中药使用的安全性和评价有毒中药和中药毒性成分已刻不容缓。常用中药北豆根被中国药典列为有毒中药，但其致毒的物质基础尚不清楚，其致毒机理更是一无所知。近些年来我们课题组首次发现北豆根主要成份蝙蝠葛碱具肺毒性，可导致肺细胞的凋亡。还发现蝙蝠葛碱被P450酶代谢成具亲电性化学活性的代谢产物，且该活性代谢产物与蝙蝠葛碱的毒性有紧密的关系。本项目在这一工作基础上，将1）研究蝙蝠葛碱活性代谢产物与肺细胞蛋白质的化学共价结合，考察蛋白结合和蝙蝠葛碱肺毒性的相关性；2）鉴定与蝙蝠葛碱代谢物结合的关键蛋白；3）探明P450 3A5酶在蝙蝠葛碱肺毒性的作用；4）解析蝙蝠葛碱的结构和毒效关系。本项目将通过多学科交叉研究，阐明蝙蝠葛碱肺毒性的分子机理，为寻找有毒中药北豆根的致毒物质基础及临床北豆根解毒治疗方案提供理论依据。

随着中药的全球化，保证中药使用的安全性和评价有毒中药和中药毒性成分已刻不容缓。常用中药北豆根被中国药典列为有毒中药，但其致毒的物质基础尚不清楚，其致毒机理更是一无所知。近些年来我们课题组首次发现北豆根主要成份蝙蝠葛碱具肺毒性，可导致肺细胞的凋亡。还发现蝙蝠葛碱被P450酶代谢成具亲电性化学活性的代谢产物，且该活性代谢产物与蝙蝠葛碱的毒性有紧密的关系。本项目在这一工作基础上，1）建立了Cyp3a5转基因细胞株；2）明确了P450 3A5酶在蝙蝠葛碱和汉防己甲素代谢活化中的关键作用；3）建立了蝙蝠葛碱代谢活化生成的蛋白加合物的检测方法；3）确认了蝙蝠葛碱导致的蛋白共价结合与其肺毒性成正比例关系；4）发现小檗胺（小檗碱类似物、双苄异喹啉生物碱）也可被代谢活化，被P450 3A酶代谢成具亚甲基醌结构具反应性代谢产物; 5) 研制了具高灵敏度高选择性检测谷胱甘肽和巯基小分子化合物分析方法。本项目通过多学科交叉研究，阐明了蝙蝠葛碱肺毒性的分子机理，为寻找有毒中药北豆根的致毒物质基础及临床北豆根解毒治疗方案提供了理论依据。