A new diphenyl ether from marine-derived fungus Aspergillus sp B-F-2

A new diphenyl ether dimethyl 2,3 ' dimethylosoate (1) together with three known compounds monomethylsulochrin (2), emodin (3), and questin (4) were isolated through bioassay-guided fractionations from the culture of a marine-derived fungus Aspergillus sp. B-F-2. The structures of these compounds were determined by spectroscopic methods. Cytotoxicities of compounds 1 and 2 against K562 cell line were preliminarily evaluated by the MTT method and flow cytometry.