剑叶龙血树内生链霉菌S009中抗菌活性成分的研究

Study of Antibacterial Components of Endophytic Streptomyces S009 from Dracaena Cochinchinensis

目的对剑叶龙血树内生链霉菌S009中抗菌活性成分进行研究。方法采用Sephadex LH-20、反相柱色谱、硅胶柱层析及HPLC对S009菌株的发酵产物进行分离纯化,并通过MS、NMR等波谱技术鉴定其结构。结果从S009菌株中分离并鉴定了4个大环四重内酯类化合物,分别为nonactin(1)、monactin(2)、dinactin(3)和trinactin(4)。活性结果显示化合物3和4对多种G^(+)菌、G^(–)菌和白色念珠菌均显示较强的抗菌活性。另外,化合物2~4还具有很强的抗耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)活性,其对所测试的多种MRSA菌株的最低抑制浓度(minimum inhibitory concentration,MIC)均小于或等于阳性药万古霉素(1~4μg·mL^(-1)),尤其以化合物3活性最为显著(MIC≤0.125μg·mL^(-1))。结论本研究结果不仅可为研制新型抗MRSA药物提供先导化合物,同时对有效利用和保护珍稀濒危植物剑叶龙血树资源具有重要意义。

OBJECTIVE To investigate the antibacterial components of endophytic Streptomyces S009 from Dracaena cochinchinensis.METHODS The fermentation extracts of S009 were isolated and purified by Sephadex LH-20,reversed phase column chromatography,silica gel column chromatography and semi-preparative HPLC.The chemical structures were identified by MS and NMR spectral analysis.RESULTS Four macrotetrolide components,including nonactin(1),monactin(2),dinactin(3)and trinactin(4),were isolated and identifed from S009.The bioactivity results showed that compounds 3 and 4possessed strong antibacterial activity against various G^(+) bacteria,G^(-) bacteria and Candida albicans.In addition,compounds 2–4also had strong anti-methicillin-resistant Staphylococcus aureus(MRSA)activity,and the minimum inhibitory concentration(MIC)values of them against a variety of tested MRSA strains were less than or equal to that of positive drug,vancomycin(MIC:1–4μg·mL^(-1)).Especially,compound 3 had the most significant activity(MIC≤0.125μg·mL^(-1)).CONCLUSION The results of this study can not only provide lead compounds for developing new anti-MRSA drugs,but also has important meaning for the effective utilization and protection of the rare and endangered Dracaena cochinchinensis.