Biotransformation of the isoflavonoids biochanin A, formononetin, and glycitein by Eubacterium limosum.
Eubacterium limosum (ATCC 8486), a strict anaerobe from the human intestinal tract that is capable of O-demethylation of several compounds, was tested for the ability to metabolize three methoxylated isoflavonoids, biochanin A, formononetin, and glycitein. High-performance liquid chromatography elution profiles of metabolites produced from biochanin A, formononetin, and glycitein showed peaks that had identical retention times to authentic genistein, daidzein, and 6,7,4'-trihydroxyisoflavone, respectively. The metabolites were identified, using an on line liquid chromatography-electrospray mass spectrometer. E. limosum produced 61.4 microM of genistein and 13.2 microM of daidzein from 100 microM of biochanin A and formononetin, after 26 days incubation. O-demethylase activity is cell-associated and was not detected in the extracellular fraction of bacterial culture. This is the first study in which conversion of biochanin A, and formononetin to more potent phytoestrogens by a bacterium has been shown.
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Division of Microbiology, National Center for Toxicological Research, US FDA, Jefferson, AR 72079, USA.
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D000693:Anaerobiosis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005051:Eubacterium / Q000254:growth & development / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D019833:Genistein / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007529:Isoflavones / Q000737:chemistry / Q000378:metabolism*; D010090:Oxidoreductases, O-Demethylating / Q000378:metabolism
D007529:Isoflavones; C007768:formononetin; C086566:glycitein; D019833:Genistein; D010090:Oxidoreductases, O-Demethylating; C004541:biochanin A