Novel quinazolinones and enniatins from Fusarium lateritium Nees

Abstract

Fusarium lateritium Nees is a natural antagonist of the plant pathogen Eutypa armeniacae. In an effort to show that this biological phenomenon is chemically mediated, the bioactive metabolites of F. lateritium were investigated. The cytotoxic alkaloids 2-(1-hydroxyethyl)-4(3H)quinazolinone (1) and 2-acetyl-4(3H)quinazolinone (2), and the three cyclohexadepsipeptides, enniatins B (3), B1 (4), and A1 (5), were isolated and characterized. Metabolites 3, 4, and 5 were found to exhibit strong antifungal activity against E. armeniacae. The structures of the novel metabolites 1 and 2 were elucidated by spectroscopic analysis and that of 2 was confirmed by X-ray crystallography. The absolute stereochemistry of 1 was investigated by 1H and I9F NMR analysis of its Mosher ester derivative.