短刺小克银汉霉对甘草次酸的生物转化

目的：使用生物催化技术探讨甘草次酸（GA）的羟基化反应, 并对转化产物进行抑菌活性的评价。方法：在 30 °C条件下, 用短刺小克银汉霉 AS 3.970 转化 GA, 反应时间为 5 d。结果：对 GA 的转化产物进过分离纯化, 得到 2 个主产物和 4个量较少的产物。其中, 2 个主产物经过 1↑H 和 13↑C NMR 鉴定为 3-酮基-7β-羟基-甘草次酸（GA-1）和 7β-羟基-甘草次酸（GA-2）, 其他产物（GA-3-GA-6）使用 HR-ESI-MS 进行结构分析。筛选了底物及其 2 个主产物对 4 株细菌和 1 株酵母菌的抑菌活性。结论：短刺小克银汉霉 AS 3.970 对 GA 具有羟基化作用。GA 和其 2 个主产物对耐药菌粪肠球菌具有良好的抑菌活性。

Biotransformation of Glycyrrhetinic Acid by Cunninghamella blakesleeana

AIM： To study the hydroxylation in glycyrrhetinic acid （GA） by biocatalysis, and evaluate the antibacterial activities of the derivatives. METHODS： The hydroxylation was performed via incubating GA with a fungus, Cunninghamella blakesleeana （C. blakesleeana） AS 3.970 at 30 ℃ for 5 days. RESULTS： GA was converted into two major derivatives and four minor derivatives. The two major derivatives were isolated and elucidated as 3-oxo-7β-hydroxy-glycyrrhetinic acid （GA-1） and 7β-hydroxy-glycyrrhetinic acid （GA-2） based on their spectral data, and other derivatives （GA-3-GA-6） were identified by HR-ESI-MS. The antibacterial activities of substrate and two major derivatives were evaluated on four bacteria strains and one yeast strain. CONCLUSION： Cunninghamella blakesleeana AS 3.970 has the capability of hydroxylation for GA. The two major derivatives and GA were found to have considerable activities against drug-resistant Enterococcusfaecalis.