Identification and Antifungal Activity of Compounds from the Mangrove Endophytic Fungus Aspergillus clavatus R7

摘要

Two new coumarin derivatives, 4,4′-dimethoxy-5,5′-dimethyl-7,7′-oxydicoumarin (>1), 7-(γ,γ-dimethylallyloxy)-5-methoxy-4-methylcoumarin (>2), a new chromone derivative, (S)-5-hydroxy-2,6-dimethyl-4H-furo[3,4-g]benzopyran-4,8(6H)-dione (>5), and a new sterone derivative, 24-hydroxylergosta-4,6,8(14),22-tetraen-3-one (>6), along with two known bicoumarins, kotanin (>3) and orlandin (>4), were isolated from an endophytic fungus Aspergillus clavatus (collection No. R7), isolated from the root of Myoporum bontioides collected from Leizhou Peninsula, China. Their structures were elucidated using 1D- and 2D- NMR spectroscopy, and HRESIMS. The absolute configuration of compound >5 was determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. Compound >6 significantly inhibited the plant pathogenic fungi Fusarium oxysporum, Colletotrichum musae and Penicillium italicum, compound >5 significantly inhibited Colletotrichum musae, and compounds >1, >3 and >4 greatly inhibited Fusarium oxysporum, showing the antifungal activities higher than those of the positive control, triadimefon.