Dihydrodaidzein ((±)-Dihydrodaidzein)-producing bacteria might lead to clarification of some of the mechanisms regulating the production of equol by fecal microbiota.

Recently, we isolated a Dihydrodaidzein (DHD)-producing Clostridium-like bacterium, strain TM-40, from human feces. We investigated the effects of strain TM-40 on in vitro daidzein metabolism by human fecal microbiota from a male equol producer and two male equol non-producers. In the fecal suspension from the male equol non-producer and DHD producer, DHD was detected in the in vitro fecal incubation of daidzein after addition of TM-40. The DHD concentration increased as the concentration of strain TM-40 increased. In the fecal suspension from the equol producer, the fecal equol production was increased by the addition of strain TM-40. The occupation ratios of Bifidobacterium and Lactobacillales were higher in the equol non-producers than in the equol producer. Adding isoflavone-metabolizing bacteria to the fecal microbiota should facilitate the estimation of the metabolism of isoflavonoids by fecal microbiota[1]