Ochratoxin A: an antiinsectan metabolite from the sclerotia of Aspergillus carbonarius NRRL 369.

Ochratoxin A, a known mycotoxin with demonstrated toxicity to insects, has been isolated from the sclerotia of the fungus Aspergillus carbonarius NRRL 369. The sclerotia, harvested from a solid substrate fermentation of corn kernels at 28 degrees C, produced quantities of ochratoxin A exceeding 50 ppm/g dry weight of sclerotia. Evidence is presented that ochratoxin A accounts for the activity of the methanol extract against larvae of the detritivorous beetle Carpophilus hemipterus (Nitidulidae) (75% reduction in feeding rate) and corn ear worm Helicoverpa zea (50% mortality with 99% reduction in weight gain among surviving larvae) when incorporated into a pinto bean diet at levels less than those occurring naturally in the sclerotia.

Apiosporamide, a new antifungal agent from the coprophilous fungus Apiospora montagnei.

Bioassay-guided fractionation of an EtOAc extract from the mycelium of the coprophilous fungus Apiospora montagnei has furnished a new antifungal metabolite, named apiosporamide [1], and the known dihydroisocoumarin cis-(3R,4R)-4-hydroxymellein [4]. The structure of 1 was assigned on the basis of HMBC, HMQC, NOESY, and hrms data. Elucidation of the structure was complicated by the fact that several nmr signals appeared only under certain conditions.