Data_Sheet_4_Novel Antimicrobial Compounds as Ophiobolin-Type Sesterterpenes and Pimarane-Type Diterpene From Bipolaris Species TJ403-B1.ZIP

Six previously undescribed ophiobolin-type sesterterpenes, namely, bipolatoxins A–F (1–6); and one previously undescribed pimarane-type diterpene, namely, 1β-hydroxy momilactone A (7); together with three known compounds, namely, 25-hydroxyophiobolin I (8), ophiobolin I (9), and ophiobolin A lactone (10); were isolated and identified from the endophytic fungus Bipolaris species TJ403-B1. Their structures with absolute configurations were elucidated on the basis of extensive spectroscopic analyses (including 1D and 2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy data), single-crystal X-ray diffraction analyses, and comparison of experimental circular dichroism data. All compounds (except for 5) were evaluated for antimicrobial potential, which indicated that bipolatoxin D (4) showed significant inhibitory activity against Enterococcus faecalis with a minimum inhibitory concentration (MIC) value of 8 μg/mL, and ophiobolin A lactone (10) showed significant inhibitory activity against Acinetobacter baumannii and E. faecalis with MIC values of 8 and 8 μg/mL, respectively.

从内生真菌离蠕孢属（Bipolaris）菌株TJ403-B1中分离鉴定得到6个首次报道的蛇孢菌素型二半萜类化合物，命名为双极毒素A~F（1~6）；1个首次报道的海松烷型二萜类化合物，命名为1β-羟基米黄素A（7）；以及3个已知化合物，分别为25-羟基蛇孢菌素I（8）、蛇孢菌素I（9）与蛇孢菌素A内酯（10）。所有化合物的结构及绝对构型均通过系统的波谱分析（包括一维、二维核磁共振（NMR）及高分辨电喷雾电离质谱数据）、单晶X射线衍射分析，以及实验圆二色谱数据比对得以阐明。对除化合物5外的所有化合物进行抗菌活性评价后发现，双极毒素D（4）对粪肠球菌（Enterococcus faecalis）具有显著抑制活性，最低抑菌浓度（MIC）为8 μg/mL；蛇孢菌素A内酯（10）对鲍曼不动杆菌（Acinetobacter baumannii）与粪肠球菌均具有显著抑制活性，对应的MIC值分别为8 μg/mL和8 μg/mL。