Microbial hydroxylation and methylation of genistein by Streptomycetes

Streptomyces griseus (ATCC 10137) and Streptomyces catenulae (ATCC 23893) w ere used to convert genistein-5,7,4'-trihydroxyisoflavone (1)-a major isofl avone found in soybeans, into five metabolites, four of which were previous ly unknown. These were 5,7,3',4'-tetrahydroxy-8-methylisoflavone (5), 5,7,3 ',4'-tetrahydroxy-8-methylisoflavanone (4), 5,7,4'-trihydroxy-3'-methoxyiso flavone (5), 5,7,8,3',4'-pentahydroxyisoflavone (7), and the known compound , 5,7-dihydroxy-3',4'-dimethoxyisoflavone (6). Identities of these metaboli tes were established by HRFABMS and 1D and 2D NMR correlation spectroscopy.