一株特殊生境荒漠药用植物沙蓬内生真菌Rhinocladiella similis中苯甲酸大环内酯化合物

Resorcylic acid analogs from the desert plant endophytic fungus Rhinocladiella similis

从一株特殊生境荒漠药用植物沙蓬的内生真菌Rhinocladiella similis中分离得到4个苯甲酸大环内酯化合物,包括2个新化合物rhinoclactones E(2)和F(1)、2个已知化合物8,9-dihyrogreensporone D(3)和8,9-dihydrogreensporone A(4)。基于高分辨质谱与核磁共振谱数据以及相关文献比对,确定了新化合物与已知化合物的结构。化合物1和2是一对立体异构体,在大环内酯环中并有一个呋喃环,这种环系统在自然界比较稀少。化合物1-4对3株肿瘤细胞株和植物病原真菌没有抑制活性。本结果进一步丰富了该真菌的化学成分研究,暗示特殊生境荒漠植物内生真菌具有产生结构新颖的次级代谢产物的潜力,是发现新活性天然产物的一个新的重要宝库;此外,根据化合物的结构特征与生物活性结果,本文还探讨了这些化合物潜在的生态学功能。

Four resorcylic acid lactones(1-4) including two new analogs rhinoclactones E(2) and F(1), and two known ones 8,9-dihyrogreensporone D(3) and 8,9-dihydrogreensporone A(4) were isolated from the endophytic fungus Rhinocladiella similis collected from desert plant Agriophyllum squarrosum. The structures of the two new compounds(1 and 2) were determined on the basis of HRESI-MS and NMR data in comparison with the data of literatures. Compounds 1 and 2 are a pair of stereo-isomers with a unique furan ring fused in the macrolide ring, which are rare in nature. Compounds 1-4 showed no inhibitory effects against three cancer cell lines and plant pathogens. The results imply that endophytic fungi inhabiting desert plants have potential to produce secondary metabolites with novel structures, and are one of vital resources for natural product discovery. Based on the structural features and biological effects, the possible ecological role of these compounds(1-4) was suggested.