The mycoparasite Humicola fuscoatra NRRL 22980 was isolated from a sclerotium of Aspergillus flavus that had been buried in a cornfield near Tifton, Ga. When grown on autoclaved rice, this fungus produced the antifungal metabolites monorden, monocillin IV, and a new monorden analog. Each metabolite produced a clear zone of inhibition surrounding paper assay disks on agar plates seeded with conidia of A. flavus. Monorden was twice as inhibitory to A. flavus mycelium extension (MIC > 28 μg/ml) as monocillin IV (MIC > 56 μg/ml). Cerebrosides C and D, metabolites known to potentiate the activity of cell wall-active antibiotics, were separated from the ethyl acetate extract but were not inhibitory to A. flavus when tested as pure compounds. This is the first report of natural products from H. fuscoatra.

A new benzodiazepine, sclerotigenin (1), was isolated from organic extracts of the sclerotia of Penicillium sclerotigenum (NRRL 3461) along with two known griseofulvin analogues. The structure of 1 was determined primarily by analysis of 1H NMR, 13C NMR, HMQC, and HMBC data. Compound 1 was the major component of the CH2Cl2 extract of P. sclerotigenum sclerotia and is responsible for most of the antiinsectan activity of the extract against the crop pest Helicoverpa zea.