ISOLATION AND BIOLOGICAL EVALUATION OF SECONDARY METABOLITES OF THE ENDOPHYTIC FUNGUS Aspergillus fumigatus FROM Astragalus membranaceus

摘要

Endophytic fungi are eukaryotic organisms that live inside plant tissues and are usually specific at the host species level [1, 2]. Endophytic fungi show high potential as sources of novel antimicrobial, antiviral, anticancer, antioxidant, and insecticidal compounds [3]. In the course of our search for biologically active metabolites of endophytic fungi from Chinese medicinal plants, an endophytic fungus, Aspergillus fumigatus, was isolated from the root of Astragalus membranaceus. The EtOAc extract of the culture showed significant antimicrobial activity. This prompted us to carry out secondary-metabolite studies on the fungus, which resulted in the isolation of eight active compounds, ergosterol (1), cerevisterol (2), ergosterol peroxide (3), fumitremorgin B (4), fumitremorgin C (5), verruculogen (6), cyclotryprostatins B (7), and fumiquinazoline J (8). Herein we describe the isolation, structural elucidation, and biological test of its secondary metabolites.