华蟾毒精和羟基华蟾毒精的人肠内细菌代谢研究

目的：研究人肠内细菌对蟾酥中主要成分华蟾毒精和羟基华蟾毒精的代谢。方法：采用体外人肠内细菌粗酶与华蟾毒精和羟基华蟾毒精温孵法；根据波谱学和化学数据鉴定代谢产物的结构；根据原形化合物和代谢产物的体外抑制人癌细胞系(HCT-8、KB、BGC、BIU 和HeLa )的生长评价其抗肿瘤活性。结果：华蟾毒精可由人肠内细菌代谢产生去乙酰基华蟾毒精；羟基华蟾毒精可由人肠内细菌代谢产生去乙酰基羟基华蟾毒精；原形化合物具有强抑制人癌细胞生长的活性，而其代谢产物无活性。结论：华蟾毒精和羟基华蟾毒精由肠内细菌代谢而失活。

Studies on the metabolism of cinobufagin and cinobufotalin by human intestinal bacteria

To study metabolism of cinobufagin and cinobufotalin, which are main constituents in Venenum Bufonis by human intestinal bacteria. Methods: The cinobufagin and cinobufotalin were incubated with crude enzymes of human intestinal bacteria in vitro . The structures of metabolites were determined on the basis of spectroscopic and chemical evidence. The inhibitory effects of cinobufagin, cinobufotalin and their metabolites on the growth of human tumorcell lines (HCT 8, KB, BGC, BIU and HeLa) were evaluated by bioassay in vitro . Results: Cinobufagin and cinobufotalin were converted to deacetylcinobufagin and deacetylcinobufotalin by human intestinal bacteria, respectively. The primary compounds showed potentially inhibitory effects on several lines of human tumor cells, but the metabolites showed no effect on them in vitro .Conclusion: These results suggest that cinobufagin and cinobufotalin are converted to deacetylcinobufagin and deacetylcinobufotalin and thereby deactivated by human intestinal bacteria. The metabolites do not play an important role in the antitumor action of cinobufagin and cinobufotalin.