七叶树皂苷-Ia的人肠内细菌生物转化产物及其抗肿瘤活性研究

目的:探讨人肠内细菌和短乳杆菌粗酶转化七叶树皂苷-Ia,阐明转化产物结构,研究其抗肿瘤活性.方法:采用人肠内细菌和短乳杆菌粗酶分别与七叶树皂苷-Ia共温孵方法,通过色谱技术分离、纯化转化产物,应用波谱技术确定转化产物结构.结果:七叶树皂苷-Ia可由人肠内细菌和短乳杆菌粗酶转化产生异七叶树皂苷Ia、去酰基七叶树皂苷I、21β-O-巴豆酰基原七叶树皂苷元和原七叶树皂苷元.去酰基七叶树皂苷I对小鼠肉瘤S-180、肝癌和肺癌细胞的生长具有抑制作用.结论:七叶树皂苷-Ia是"前药",人肠内细菌和短乳杆菌粗酶能够转化七叶树皂苷-Ia;转化产物去酰基七叶树皂苷I有抗肿瘤活性,是有开发潜力的抗肿瘤候选药物.

Studies on the biotransformation of escin Ia by human intestinal bacteria and the anti-tumor activities of desacylescin Ⅰ

OBJECTIVE: To study Biotransformation of escin Ia by the crude enzymes of human intestinal bacteria and Lactobacillus brevis, determine the structures of biotransformation products and assay the inhibitory effect of desacylescin I on the tumor cell growth. METHODS: The escin Ia was incubated with crude enzymes of human intestinal bacteria and Lactobacillus brevis in vitro, respectively. The biotransformation products were isolated and purified by the chromatographic methods and the structures were determined by the spectroscopic techniques. RESULTS: Escin Ia was converted into isoescin Ia, desacylescin I, 21beta-O-tigloylprotoaescigenin and protoaescigenin by crude enzymes of human intestinal bacteria and Lactobacillus brevis. Desacylescin I showed potentially inhibitory effects on tumor cell growth of mouse sarcoma-180, hepatic carcinoma H(22) and lung carcinoma in vivo. CONCLUSION: The results suggest that Escin Ia was a prodrug and its structure can be converted by human intestinal bacteria and Lactobacillus brevis. Desacylescin I as a biotransformation product showed potentially inhibitory effects on mouse tumor, and a potential candidate for anti tumor agents.