title: Production of equol from daidzein by gram-positive rod-shaped bacterium isolated from rat intestine.
abstract: Isoflavones (mainly daidzein and genistin) belong to the flavonoid group of compounds and are classified as phytoestrogens. In the intestine, daidzin is converted to daidzein by beta-glucosidase, and then daidzein is converted to O-desmethylangolensin (O-DMA) or equol via dihydrodaidzein by enzymes of intestinal bacteria. We isolated, for the first time, an anaerobic gram-positive rod-shaped strain capable of producing equol from daidzein. Its 16S rDNA gene sequence (1428 bp) showed 99% similarity with that of the human intestinal bacterium SNU-Julong 732 (AY310748) and 93% similarity with that of Eggerthella lenta ATCC 25559(T) (AF292375). This strain converted daidzein to equol via dihydrodaidzein in an equol-assay medium anaerobically. The addition of butyric acid and arginine increased the conversion ratio of daidzein to equol 4.7- and 4.5-fold, respectively.
authors.affiliation: Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Sapporo, Hokkaido, Japan. kimiko-m@chem.agr.hokudai.ac.jp
authors.forename: Kimiko
authors.initials: K
authors.lastname: Minamida
authors.forename: Michiko
authors.initials: M
authors.lastname: Tanaka
authors.forename: Ayumi
authors.initials: A
authors.lastname: Abe
authors.forename: Teruo
authors.initials: T
authors.lastname: Sone
authors.forename: Fusao
authors.initials: F
authors.lastname: Tomita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hara
authors.forename: Kozo
authors.initials: K
authors.lastname: Asano
mesh_terms: D039903:Actinobacteria / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D000818:Animals; D001483:Base Sequence; D060754:Equol; D006801:Humans; D007422:Intestines / Q000382:microbiology; D007529:Isoflavones / Q000096:biosynthesis* / Q000378:metabolism* / Q000494:pharmacology; D008969:Molecular Sequence Data; D048789:Phytoestrogens / Q000378:metabolism* / Q000494:pharmacology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D051381:Rats
chemical_list: C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D007529:Isoflavones; D048789:Phytoestrogens; D012336:RNA, Ribosomal, 16S; D060754:Equol; C004742:daidzein