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

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