罗布泊来源胀果甘草根际枯草芽孢杆菌GA21次生代谢产物结构与活性初步研究

Preliminary study of structures and bioactivities of the secondary metabolites produced by Bacillus subtilis strain GA21

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,purify and identify the secondary metablites from the fermentation broth produced by Bacillus subtilis strain GA21.Methods Different column chromatographies were used to isolate and purify the secondary metabolites.HR-ESI-MS,1D-NMR and 2D-NMR were used to analyze the structure of compounds GA21-20 and GA21-26.Agar plating method was used to analyze the inhibition activity of the secondary metabolites against Staphylococcus aureus,Escherichia coli,Pyricularia oryzae and Candida Albican.Results GA21-20 and GA21-26 were purified and structurally identified as a group of isocoumarin antibiotics.GA21-20 has the same structure with Amicoumacin B,but does not have anti-bacterial and anti-fungus activity.GA21-26 is a new member of isocoumacin antibiotic with the molecular formula of C21H29O7N3 and molecular weight of 435.2,and has anti-fungus activity.GA21-26 inhibits the growth of plant pathogenic fungi Pyricularia oryzae and Candida Albicans at 80μg per paper and 2.5μg per paper respectively.Conclusion A series of 3,4-dihydroisocoumarin can be isolated from the secondary metabolites produced by strain GA21 and more secondary metabolites need to be discovered from the fermentation broth of the strain GA21.