Fungal metabolism of the prenylated isoflavone licoisoflavone A.

Abstract

Cultures of Aspergillus flavus and Botrytis cinerea have been found to rapidly convert the fungitoxic isoflavone licoisoflavone A [5, 7, 2', 4'-tetrahydroxy-3'-(3, 3-dimethylallyl)isoflavone] into products with reduced antifungal activity, as judged from TLC plate bioassays against the growth of Cladosporium herbarum. Both fungi produced the same five metabolites, but often in greatly differing quantities. Using physico-chemical procedures, the metabolites were characterized as a glycol (2'', 3''-dihydrodihydroxylicoisoflavone A), two dihydrofurano-isoflavones (one of which was identical with lupinisoflavone D found in Lupinus albus roots) and two hydroxydihydropyranoisoflavones.