关键词: 北桑寄生, 内生真菌, 抗氧化活性, 抑菌活性, 次级代谢产物

Abstract: 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.

Key words:  , Loranthus tanakae, endophytic fungi, antioxidant activity, antibacterial activity, secondary metabolites