tetrahydrodaidzein and daidzein

Isoflavones intake is associated with health benefits. The metabolism of isoflavones by bacteria plays a key role in their biotransformation. Therefore, commercial soy drink was fermented by 11 lactic acid bacteria (LAB) and 9 bifidobacteria strains. The majority of the strains showed deglycosylation of the isoflavone glycosides present in soy drink and appearance of the aglycones daidzein, genistein and glycitein. Moreover, we observed the further transformation of daidzein into O-desmethylangolensin (O-DMA) and tetrahydrodaidzein, alongside with dihydrodaidzein (DHD) and a putative isomer of DHD. On the other hand, genistein was transformed by nearly all strains into 6-hydroxy-O-desmethylangolensin (6-hydroxy-O-DMA), but no dihydrogenistein production was registered. A high concentration of 2-(4-hydroxyphenyl)-propionic acid was observed, suggesting the degradation of O-DMA and 6-hydroxy-O-DMA. The potential of LAB and Bifidobacterium strains to produce functional soy drink enriched with bioactive isoflavones is demonstrated in this work.

Topics: Bifidobacterium; Fermented Foods; Genistein; Humans; Isoflavones; Lactobacillales; Propionates; Soy Milk

Topics: Actinobacteria; Equol; Gene Expression Regulation, Bacterial; Genes, Bacterial; Isoflavones; Multigene Family; Regulatory Elements, Transcriptional

To identify human subjects harbouring intestinal bacteria that bioactivate daidzein to equol using a targeted PCR-based approach.. In a pilot study including 17 human subjects, equol formation was determined in faecal slurries. In parallel, faecal DNA was amplified by PCR using degenerate primers that target highly conserved regions of dihydrodaidzein reductase and tetrahydrodaidzein reductase genes. PCR products of the expected size were observed for six of the eight subjects identified as equol producers. Analysis of clone libraries revealed the amplification of sequences exclusively related to Adlercreutzia equolifaciens in four of the subjects tested positive for equol formation, whereas in three of the equol producers, only sequences related to Slackia isoflavoniconvertens were observed. No amplicons were obtained for one equol-forming subject, thus suggesting the presence of nontargeted alternative genes. Amplicons were only sporadically observed in the nonequol producers.. The majority of human subjects who produced equol were also detected with the developed PCR-based approach.. The obtained results shed light on the distribution and the diversity of known equol-forming bacterial species in the study group and indicate the presence of as yet unknown equol-forming bacteria.

Topics: Adult; Bacteria; Bacterial Proteins; Equol; Feces; Female; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Isoflavones; Male; Oxidoreductases; Pilot Projects; Polymerase Chain Reaction