大黄鱼共生菌Bacillus coagulans LL1103的代谢产物研究

Secondary metabolites of Bacillus coagulans LL1103 from large yellow croaker (Pseudosciaena crocea)

摘要:

[目的]研究大黄鱼共生菌Bacillus coagulans LL1103的次生代谢产物及其抑菌活性。[方法]利用色谱层析技术对B.coagulans LL1103发酵液乙酸乙酯和正丁醇提取物进行分离纯化；运用波谱技术鉴定化合物的结构；采用微量肉汤稀释法对化合物进行抗菌活性测定。[结果]从大黄鱼内生菌B.coagulans LL1103发酵液中分离并鉴定9个环二肽类化合物，分别为：（1）环（4-羟基-脯氨酸-亮氨酸）、（2）环（异亮氨酸-丙氨酸）、（3）环（脯氨酸-缬氨酸）、（4）环（脯氨酸-苯丙氨酸）、（5）环（脯氨酸-亮氨酸）、（6）环（甘氨酸-丙氨酸）、（7）环（脯氨酸-甘氨酸）、（8）环（脯氨酸-丙氨酸）和（9）环（络氨酸-甘氨酸）。活性评价显示化合物3、7和9对大肠埃希菌（Escherichia coli）具有较强抑制作用，最低抑菌浓度（minimal inhibitory concentration，MIC）分别为8.0、4.0和16.0μg/mL。[结论]从大黄鱼共生菌B.coagulans LL1103的发酵液中分离得到3个对大肠埃希菌（E.coli）具有较好抑制活性的化合物。

Abstract:

[Objective] To mine new antimicrobial agents from Bacillus coagulans LL1103 isolated from large yellow croaker.[Methods] The ethyl acetate and n-butanol extracts of B. coagulans LL1103 fermentation broth were separated and purified by chromatographic techniques, and their structures were identified based on spectral analysis. Their antibacterial activities were detected by micro-broth dilution method. [Results] From the fermentation broth of B. coagulans LL1103, 9 cyclic dipeptides (1-9) were obtained as (1) cyclo-(4-Hydroxyl-Pro-Leu), (2) cyclo-(Ile-Ala), (3) cyclo-(Pro-Val), (4) cyclo-(Pro-Phe), (5) cyclo-(Pro-Leu), (6) cyclo-(Gly-Ala), (7) cyclo-(Pro-Gly), (8) cyclo-(Pro-Ala) and (9) cyclo-(Tyr-Gly). Cyclic dipeptides 3, 7 and 9 showed strong antibacterial activities against Escherichia coli with minimal inhibitory concentration values of 8.0, 4.0 and 16.0 μg/mL, respectively. [Conclusion] Three compounds showed remarkably biological effect on the growth of E. coli.