Dihydrogenistein-Producing Bacterium TM-40 Isolated from Human Feces

Abstract

Recently there has been great interest in the biological effects of isoflavones. Intestinal flora play an important role in the metabolism and bioavailability of isoflavones. To estimate the effects of dietary isoflavones on physiological function, it is also important to estimate the role of intestinal flora on the metabolism and absorption of isoflavones. However, to date there have been few reports of intestinal bacteria that metabolize genistein into dihydrogenistein. Formerly, we isolated the dihydrodaidzein-producing intestinal bacterium TM-40 from a healthy boy's feces. The strain TM-40 produce dihydrodaidzein from daidzein and daidzin. The 16S rRNA partial sequence of strain TM-40 showed a 93% similarity to that of Coprobacillus catenaformis (Accession no: AB030218). This strain seems to be a new species and was found to metabolize genistein into dihydrogenistein. We demonstrate that the dihydrogenistein-producing intestinal bacterium was harbored in a healthy boy's feces. This is the first report of a dihydrogenistein-producing intestinal bacterium being harbored in a healthy boy's feces.