北桑寄生内生真菌的分离及其次级代谢产物分析

Isolation of endophytic fungi from Loranthus tanakae and analysis of its secondary metabolites

首次对药用植物北桑寄生叶片中的内生真菌进行分离纯化,从中筛选出具有较高生物活性的菌株,鉴定此菌株并对其次级代谢产物进行初步分离。采用组织块法分离内生真菌,对其进行抗氧化活性和抑菌活性筛选;通过形态学和分子生物学方法鉴定其种属;运用柱色谱、重结晶等方法分离次级代谢产物,波谱学鉴定其结构。从北桑寄生叶片中分离纯化得到29株内生真菌,检测得到一株具有较高抗氧化和抑菌活性的菌株,鉴定为Alternaria alternata,从该菌次级代谢产物中首次分离得到3个单体化合物,分别为alternariol-5-O-methyl ether(1)、alternariol(2)、cis,cis-9,12-octadecadienoic acid(3)。化合物1和2具有较弱的抗氧化活性,化合物1和3表现出一定的抑菌活性。

In this study,endophytic fungi were isolated and purified for the first time from the leaves of a medicinal plant,Loranthus tanakae.A strain with high biological activity was screened and identified,and its secondary metabolites were preliminarily isolated.Tissue inoculation culture was used for isolation of the endophytic fungi,and then anti-oxidant and bacteriostatic activities of the isolate were tested.The selected isolated was identified based on morphological analysis combined with molecular biological method.The secondary metabolites of the identified strain were isolated with column chromatography and recrystallization,and determined by spectroscopy.Among 29 strains isolated from L.tanakae,the BS27 had high antioxidant and antibacterial activities,which was identified as Alternaria alternata.Three compounds were isolated from its secondary metabolites and identified as alternariol-5-O-methyl ether(1),alternariol(2) and cis,cis-9,12-octadecadienoic acid(3),respectively.Compound 1 and 2 displayed weak antioxidant activity,while compound 1 and 3 exhibited antibacterial activity.