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

关键词:  剑叶龙血树  内生链霉菌  结构鉴定  大环四重内酯类成分  耐甲氧西林金黄色葡萄球菌

Key words:  Dracaena cochinchinensis  endophytic Streptomyces  structural elucidation  macrotetrolide components  methicillin-resistant Staphylococcus aureus

摘要:

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。

Abstract:

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 identified from S009. The bioactivity results showed that compounds 3 and 4 possessed strong antibacterial activity against various G⁺ bacteria, G^– bacteria and Candida albicans. In addition, compounds 2–4 also 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: 1–4 μg·mL^-1). Especially, compound 3 had the most significant activity (MIC≤0.125 μg·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.