Bioactive natural products from a sclerotium-colonizing isolate of Humicola fuscoatra.

Chemical studies of an organic extract from solid-substrate fermentations of the mycoparasitic fungus Humicola fuscoatra NRRL 22980, originally isolated as a colonist of Aspergillus flavus sclerotia, afforded two new unrelated compounds that we have named fuscoatroside (1) and fuscoatramide (2). The structures of these metabolites were elucidated by analysis of NMR and MS data. Fuscoatroside (1) is a triterpenoid glycoside that exhibited activity in antifungal assays against A. flavus. This extract also contained the known metabolites 7-deoxysterigmatocystin, sterigmatocystin, isosclerone, and decarestrictines A(1) and I.