Pseurotin A and 8-O-Demethylpseurotin A from Aspergillus fumigatus and Their Inhibitory Activities on Chitin Synthase

Abstract

Two inhibitors of chitin synthase were isolated from submerged cultures of an osmophilic Aspergillus fumigatus strain and identified as pseurotin A (1) and its 8-O-demethyl derivative (2). The two compounds inhibited both the solubilized and the membrane-bound forms of the enzyme, but do not have antifungal or antibacterial activities. The IC₅₀ of pseurotin A was 81 μM for the solubilized enzyme. 8-O-Demethylpseurotin was less active with an IC₅₀ of 192 μM. The structures of the compounds were elucidated by spectroscopical methods.