Three new metabolites from marine-derived fungi of the genera Coniothyrium and Microsphaeropsis

The marine sponges Ectyplasia perox and Myxilla incrustans were investigated for associated fungal strains. Among others, a Coniothyrium sp., from E. perox, and a Microsphaeropsis sp., from M. incrustans, were isolated, cultured, and investigated for their biologically active secondary metabolite contents. The new compound microsphaeropsisin (1) together with the known compounds (R)-mellein (4), (3R,4S)-hydroxymellein (5), (3R,4R)-hydroxymellein (6), and 4,8-dihydroxy-3,4-dihydro-2H-naphthalen-1-one (7) were isolated from the Microsphaeropsis sp. From culture extracts of the Coniothyrium sp., the new compounds (3S)-(3',5'-dihydroxyphenyl)butan-2-one (2) and 2-(1'(E)-propenyl)-octa-4(E), 6(Z)-diene-1,2-diol (3), together with the six known metabolites (3R)-6-methoxymellein (8), (3R)-6-methoxy-7-chloromellein (9), cryptosporiopsinol (10), phenylethanol, (p-hydroxyphenyl)ethanol, and 2-(hydroxymethyl)furan, were obtained. All structures were determined using spectroscopic methods. With the exception of 3, all compounds were tested for their antimicrobial properties, and all but 10 demonstrated significant antimicrobial activity in agar diffusion assays.