蛇足石杉中的新内生真菌及其代谢产物的分离与鉴定

Isolation and identification of secondary metabolites from a new endophyte Huperzia serrata

关键词:  球毛壳属, 内生真菌, 结构鉴定, 细胞毒活性

Key words:  Chaetomium sp., endophytic fungi, structure identification, cytotoxicity

摘要:

从蛇足石杉内生菌的次级代谢产物中寻找活性成分,为进一步开发利用蛇足石杉药用植物资源提供了新途径,但至今其内生菌代谢产物的系统性研究较为少见。种类丰富的内生真菌普遍存在于各种植物中,但蕨类植物中内生真菌的研究较少。为了寻找蛇足石杉内生菌中的细胞毒活性成分,该研究从蛇足石杉根部分离得到一株球毛壳属(Chaetomium sp.)真菌M336,对其化学成分进行了研究。对蛇足石杉内生真菌M336采用PDA固体培养基扩大发酵,发酵物经提取及乙酸乙酯萃取后,通过正相硅胶柱色谱法、Sephadex LH-20凝胶柱色谱法、薄层制备、高效液相色谱等色谱手段对其发酵物中的化学成分进行分离纯化,利用理化性质、质谱、核磁等波谱分析技术,并结合相关文献数据鉴定化合物的结构。结果表明:从内生真菌M336发酵提取物的乙酸乙酯萃取部分分离并鉴定出8个化合物,分别为chaetoviridines F、chaetoviridines E、5'-epichaetoviridin A、5'-epichaetoviridin A、xanthoquinodins Al、xanthoquinodins A2、xanthoquinodins B1和毛壳菌素。从M336中分离得到8个化合物,化合物3有一定的抑菌作用,其余化合物有一定的细胞毒活性。该研究结果丰富了蛇足石杉内生真菌球毛壳属中的天然细胞毒活性的化合物。

Abstract:

Many kinds of endophytic fungi are widely associated with various plants and a lot of systemic researches focusing on secondary metabolites of endophytes had been conducted. However, the research on endophyte in Huperzia serrata is rare, which is a traditional Chinese medicinal fern Qian Ceng Ta, belongs to Huperzia of Huperziaceae. Finding active compounds from endophytes in H. serrata can provide a new way for further exploitation resources of this medicinal plant. The purpose of this study was to search cytotoxic active compounds of endophytes from H. serrata. We isolated the chemical constitution of Chaetomium sp. M336 which was an endophytic fungus isolated in the roots of Huperzia serrata. The Chaetomium sp. M336 was fermented on solid PDA media. The fungus containing with medium was extracted with ethyl acetate:methanol:acetic acid =(80:15:5, V/V/V)mixed organic solvent, and the secondary metabolites of endophytic fungi were obtained. The compounds of the fermented extracts were separated and purified by column chromatography involving normal-phase silica gel, Sephadex LH-20 and reversed-phase semi-preparative HPLC. Their structure of the compounds were elucidated by their physical and chemical properties, including nuclear magnetic resonance(NMR)spectroscopy, and electrospray ionization mass spectrometry(ESI-MS)and according to the reported literatures. They results were as follows: eight compounds were isolated and purified from the ethyl acetate extracts of the fungus Chaetomium sp. M336. They were identified as chaetoviridines F, chaetoviridines E, 5'-epichaetoviridin A, 5'-epichaetoviridin A, xanthoquinodins Al, xanthoquinodins A2, xanthoquinodins B1, chetomin. In conclusion, eight compounds were isolated from M336. Compound 3 showed some certain anti-bacterial activity, others exhibit cytotoxicity. This preliminary work will provide information for further search on natural cytotoxic activity products of endophytic fungi from Huperzia serrata.