[Antibacterial secondary metabolites of Clonostachys rosea, an endophytic fungus from Blumea balsamifera (L.) DC]

Endophytic fungus is an important treasure trove for discovery of structurally unusual and biologically diverse compounds. A phytochemical investigation on a fungus Clonostachys rosea inhabits inner tissue of Blumea balsamifera (L.) DC. was initiatedrecently in our lab. Six pure compounds were isolated through silica gel column chromatography, sephadex LH-20, and semi-preparative HPLC techniques, with bio-guided strategy. Their structures were characterized as verticillin A (1), (S)-(+)-fusarinolic acid (2), 8-hydroxyfusaric acid (3), cerebroside C (4), 3-Maleimide-5-oxime (5), and bionectriol A (6) by analyses of NMR and MS data. All compounds were tested in vitro antibacterial activities against four strains of bacteria, Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa, and results revealed that 1, 4 and 6 display notableinhibition againstthree bacteria, with MIC values ranging from 2 to 16 μg/mL. Our findings provide references for mining novel antibiotics from endophytes originated from Li Minority medicinal plant B. balsamifera (L.) DC.

植物内生真菌一直是发现结构新颖、活性广泛的化合物的重要宝库。文中对一株艾纳香内生真菌粉红粘帚霉Clonostachys rosea 进行化学研究，通过活性跟踪手段，结合硅胶柱色谱、凝胶色谱、以及半制备液相色谱技术从该菌株的发酵提取物中共分离获得6 个单体化合物，经波谱学技术结合质谱鉴定其分别为verticillin A (1)、(S)-(+)-fusarinolic acid (2)、8-hydroxyfusaric acid (3)、cerebroside C (4)、3-Maleimide-5-oxime (5)以及bionectriol A(6)。所有化合物进行了体外抗大肠埃希菌、金黄色葡萄球菌、枯草芽孢杆菌以及铜绿假单胞菌4 株细菌的活性评价，其中1、4 和6 对3 株细菌表现出显著的抑菌活性，MIC 值2–16 μg/mL。研究结果为从黎药植物艾纳香的内生真菌中寻找新型抗生素提供重要参考。.

Keywords: Blumea balsamifera (L.) DC.; antimicrobial activity; endophytes; secondary metabolites.