Tenellic acids A-D: new bioactive diphenyl ether derivatives from the aquatic fungus Dendrospora tenella

Tenellic acids A-D (1-4) were isolated from cultures of the freshwater fungus Dendrospora tenella. The structures of these new diphenyl ether derivatives were determined primarily by analysis of NMR data. Compounds 1-4 display antimicrobial activity against Gram-positive bacteria.