Fungal Transformation of the Antifungal Isoflavone Luteone

Abstract
An antifungal isoflavone, luteone [5,7,2′,4′-tetrahydroxy-6-(3,3-dimethylallyl)isoflavone] is metabolised by cultures of Aspergillus flavus and Botrytis cinerea into 2″,3″-dihydro-3″-hydroxyluteone (AF-1), 2″,3″-dihydrodihydroxyluteone, a dihydrofuranoisoflavone (BC-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.