Coniochaetones E–I, new 4H-chromen-4-one derivatives from the Cordyceps-colonizing fungus Fimetariella sp.

Five new 4H-chromen-4-one derivatives coniochaetones E-I (1-5), along with the known compounds coniochaetones B (6) and A (7) have been isolated from solid cultures of the Cordyceps-colonizing fungus Fimetariella sp. Their structures were elucidated primarily by NMR spectroscopy and the absolute configurations of compounds 1-3 were assigned using the modified Mosher's method. Compound 4 showed weak cytotoxic activity against HeLa cells with IC50 values of 72.8 μM. The co-isolated known compound 6 showed modest inhibitory effects against Aspergilus fumigates, Fusarium oxysporum and Fusarium nivale.