Biotransformation of isoflavones by the larvae of the common cutworm (Spodoptera litura)

Biotransformation of the 5,7,4'-trimethoxyisoflavone (1), 6,7,4'-trimethoxyisoflavone (2), and 7,4'-dimethoxyisoflavone (3) by insects, Spodoptera litura was investigated. Compound 1 was transformed to 5-hydroxy-7,4'-dimethoxyisoflavone (4), 7-hydroxy-5,4'-dimethoxyisoflavone (5) and 4'-hydroxy-5,7-dimethoxyisoflavone (6) by S. litura. Compounds 2 and 3 were hardly metabolized by S. litura. This suggested that compound 1 was converted to compounds 4, 5 and 6 by demethylation at the C-5, C-7 and C-4' position, respectively.