New diketopiperazine metabolites from the sclerotia of Aspergillus ochraceus.

Three new diketopiperazine-containing metabolites 1-3 have been isolated from the sclerotia of Aspergillus ochraceus (NRRL 3519) by chromatography on Sephadex LH-20 and reversed-phase hplc. The structures of these compounds were established using extensive high-field 1D and 2D nmr experiments. All three compounds cause moderate reduction in weight gain in assays against the lepidopteran crop pest Helicoverpa zea.