Fungal transformation of the antifungal isoflavone luteone.

Abstract

An antifungal isoflavone, luteone [5, 7, 2′, 4′-tetrahydroxy-6-(3, 3-diniethylallyl)isoflavone] is metabolised by cultures of Aspergillus flavus and Botrytis cinerea into 2″, 3″-dihydro-3″-hydroxyluteone (AF- 1), 2″, 3″-dihydrodihydroxyluteone, a dihydrofuranoisoflavone (BG-1) and a dihydropyranoisoflavone. The structures of the metabolites were elucidated by physico-chemical and chemical procedures. The major metabolites, AF-1 and BC-1 are much less toxic than luteone against Cladosporium herbarum. The possible metabolic pathways are briefly discussed.