Oxirapentyns B-D produced by a marine sediment-derived fungus Isaria felina (DC.) Fr

► Three new oxirapentyns were isolated from the marine-derived fungus Isaria felina. ► The absolute configuration of oxirapentyn B was established by a combination of NMR, X-ray and a Mosher's ester method. ► Antibiotic and cytotoxic properties of oxirapentyns were evaluated.