New p-terphenyl and polyketide metabolites from the sclerotia of Penicillium raistrickii

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'-desmethylterphenyllin (1); 3'-demethoxy-6'-desmethyl-5'-methoxycandidusin B (2); 6'-desmethylcandidusin B (3); and 1,3,5,6-tetrahydroxy-8-methylxanthone (4) 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.