Submitted to: Journal of Natural Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/1998
Publication Date: N/A
Citation: N/A Interpretive Summary: There is an urgent need for new sources of insecticides and leads to insecticides (i.e., new chemotypes) because many insects are developing resistance to existing products and there are few environmentally tolerable replacements. Our research program has shown that fungal survival structures called sclerotia and stromata commonly contain unique chemicals which are toxic to insects or show other forms of bioactivity relevant to agriculture and medicine. Fungal sclerotia produced by Penicillium raistrickii were examined for the ability to produce antiinsectan agents and other bioactive metabolites. Here we report three new metabolites which exhibited only mild antiinsectan activity and antibacterial activity. Griseofulvin, known primarily as an antifungal antibiotic, was responsible for the potent antiinsectan activity of the sclerotial extract. This is the first report of these metabolites from any species of Penicillium. This research is of use to other scientists interested in novel pesticides from unique sources.
Technical Abstract: Three new p-terphenyls (1-3), a new xanthone derivative (4), and two known fungal metabolites (5 and 6) have been isolated from the sclerotia of Penicillium raistrickii (NRRL 2039). The structures for 3,3"-dihydroxy-6'-desmethylcandidusin B and 1,3,5,6-tetrahydroxy-8-methylxanthone were determined on the basis of HRMS and NMR data. Although compounds 1 and 4 exhibited mild antiinsectan and antibacterial activity, griseofulvin (5) was responsible for most of the activity of the sclerotial extract in dietary assays against the corn earworm Helicoverpa zea.