Antiinsectan alkaloids: Shearinines A-C and a new paxilline derivative from the ascostromata of Eupenicillium shearii

Abstract

Four new antiinsectan indole alkaloids (1-4) have been isolated from organic extracts of the sclerotioid ascostromata of Eupenicillium shearii (NRRL 3324). These extracts also afforded five known, related metabolites (5-9). The structures of the new compounds were determined through analysis of 1H NMR, 13C NMR, HMQC, and HMBC experiments. Compounds 1-9 were isolated from fractions displaying activity in dietary assays against the corn earworm Helicoverpa zea and the dried-fruit beetle Carpophilus hemipterus, and most of the compounds show potent activity in these assays. Shearinine A (1) also exhibited activity in a topical assay against H. zea, and shearinine B (2) caused significant mortality in a leaf disk assay against the fall armyworm Spodoptera frugiperda. © 1995.