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

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。

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

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.