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目的分离鉴定枯草芽孢杆菌GA21发酵液中次生代谢产物并对其活性进行初步研究。方法采用TLC、HPLC等分离手段对次生代谢产物进行分离;通过HR-ESI质谱、1D-NMR和2D-NMR对其结构进行鉴定;以琼脂平板法检测其次生代谢产物对金黄色葡萄球菌、大肠杆菌、稻瘟菌、白色念珠菌的拮抗活性。结果分离得到两个异香豆素类次生代谢产物:GA21-20和GA21-26;其中GA21-20的化学结构与Amicoumacin B一致,但无抗细菌及真菌活性;GA21-26有抗真菌活性,但无抗细菌活性,分子量为435.20890,分子式为C21H29O7N3,是一新的3,4-二氢异香豆素类抗生素。GA21-26在2.5μg/纸片对白色念珠菌即可显示抑制活性,在80μg/纸片对水稻稻瘟菌显示抑制活性,表明GA21-26在拮抗医学条件致病真菌方面有潜在用途。结论枯草芽孢杆菌GA21能产生一系列3,4-二氢异香豆素类抗生素,其次级代谢产物值得进一步研究。
Objective To isolate and identify the secondary metabolites of Bacillus subtilis GA21 fermentation broth and study its activity. Methods The secondary metabolites were separated by TLC and HPLC. Their structures were identified by HR-ESI-MS, 1D-NMR and 2D-NMR. The secondary metabolites of the secondary metabolites were detected by agar plate assay for Staphylococcus aureus, Escherichia coli, Magnaporthe grisea, Candida albicans antagonistic activity. Results Two isocoumarins secondary metabolites were isolated: GA21-20 and GA21-26. The chemical structure of GA21-20 was consistent with Amicoumacin B, but no antibacterial and fungal activity. GA21-26 had antifungal activity, But no antibacterial activity, a molecular weight of 435.20890, the molecular formula of C21H29O7N3, is a new 3,4-dihydro isocoumarins antibiotics. GA21-26 exhibited inhibitory activity against Candida albicans at 2.5 μg / leaf and showed inhibitory activity against Magnaporthe grisea at 80 μg / leaf, suggesting that GA21-26 has potential applications against pathogenic fungi of medical conditions. Conclusion Bacillus subtilis GA21 can produce a series of 3,4-dihydroisocoumarins antibiotics, the secondary metabolites deserve further study.