Antimicrobial secondary metabolites from an endophytic fungus Aspergillus polyporicola

Two new nucleoside derivatives, kipukasins O (1) and P (2), one new cyclohexenone derivative, arthropsadiol D (5), and one new natural product, (+)-2,5-dimethyl-3(2H)-benzofuranone (6), together with eleven known compounds (3, 4, 7-15), were obtained from the culture broth of the endophytic fungus Aspergillus polyporicola R2 isolated from the roots of Synsepalum dulcificum. Among them, the absolute configuration of compound 5 was determined by quantum chemical calculations of NMR chemical shifts and ECD spectrum. The antimicrobial activities of these compounds were evaluated. Compound 11 exhibited obvious inhibitory activity against MRSA, Staphylococcus aureus, Salmonella typhimurium, Botrytis cinerea, and Fusarium graminearum with MIC values of 4, 4, 4, 32, and 16 μg/mL, respectively. Compound 12 exhibited antibacterial activity against S. typhimurium and MRSA with MIC values of 4 and 16 μg/mL. Compound 6 exhibited antifungal activity against F. graminearum with MIC value of 32 μg/mL.

从神秘果（Synsepalum dulcificum）根部内生真菌多孑座曲霉（Aspergillus polyporicola）R2的培养液中获得了两种新的核苷衍生物，基普卡辛O（1）和P（2），一种新的环己烯酮衍生物，节荚藻二醇D（5），以及一种新的天然产物，（+）-2,5 - 二甲基-3(2H)-苯并呋喃酮（6），还有11种已知化合物（3、4、7 - 15）。其中，化合物5的绝对构型通过核磁共振化学位移和电子圆二色谱的量子化学计算确定。对这些化合物的抗菌活性进行了评估。化合物11对耐甲氧西林金黄色葡萄球菌、金黄色葡萄球菌、鼠伤寒沙门氏菌、灰葡萄孢菌和禾谷镰刀菌表现出明显的抑制活性，其最低抑菌浓度（MIC）值分别为4、4、4、32和16μg/mL。化合物12对鼠伤寒沙门氏菌和耐甲氧西林金黄色葡萄球菌表现出抗菌活性，其MIC值分别为4和16μg/mL。化合物6对禾谷镰刀菌表现出抗真菌活性，其MIC值为32μg/mL。