Dihydroisocoumarin Derivatives of Mangrove Endophytic Fungus Microsphaeropsis sp. Isolated from the South China Sea

The secondary metabolites of the mangrove endophytic fungus Microsphaeropsis sp.from the South China Sea were first studied.Eight dihydroisocoumarin derivatives were isolated from the ethyl acetate extract of the fermentation.Their structures were identified by comprehensive spectroscopic methods as 4-hydroxy-8-O-methylmellein(1),mellein(2),4-hydroxymellein(3),5-hydroxymellein(4),4-hydroxy-3,5-dimethylmellein(5),5-methylmellein(6),7-hydroxymellein(7) and 5-carboxymellein(8).Compound 1 was isolated as a natural compound for the first time and compounds 4,5,6,7,8 were first isolated from the fungus Microsphaeropsis sp.