Conversion of Daidzein and Genistein by an Anaerobic Bacterium Newly Isolated from the Mouse Intestine

• Published in: Applied and Environmental Microbiology Vol. 74; no. 15; pp. 4847 - 4852
• Main Authors: Matthies, Anastasia, Clavel, Thomas, Gütschow, Michael, Engst, Wolfram, Haller, Dirk, Blaut, Michael, Braune, Annett
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.08.2008; American Society for Microbiology (ASM)
• Subjects: Animals; Bacteria; Bacteria, Anaerobic - isolation & purification; Bacteria, Anaerobic - metabolism; Biodegradation; Biological and medical sciences; Biotransformation; Chromatography, High Pressure Liquid; Coriobacteriaceae; daidzein; Dietary supplements; Digestive system; Digestive tract; Enzymes; Female; Fundamental and applied biological sciences. Psychology; gene induction; genistein; Genistein - metabolism; Gram-positive bacteria; Gram-Positive Bacteria - isolation & purification; Gram-Positive Bacteria - metabolism; Ileum - microbiology; intestines; Isoflavones - metabolism; Metabolism; Mice; Mice, Inbred C57BL; Microbiology; Molecular Sequence Data; Rodents; Spectrometry, Mass, Electrospray Ionization; Bacteria; Vertebrata; Mammalia; Mouse; Anaerobe; Rodentia
• ISSN: 0099-2240; 1098-5336; 1098-5336; 1098-6596
• DOI: 10.1128/aem.00555-08

The metabolism of isoflavones by gut bacteria plays a key role in the availability and bioactivation of these compounds in the intestine. Daidzein and genistein are the most common dietary soy isoflavones. While daidzein conversion yielding equol has been known for some time, the corresponding formation of 5-hydroxy-equol from genistein has not been reported previously. We isolated a strictly anaerobic bacterium (Mt1B8) from the mouse intestine which converted daidzein via dihydrodaidzein to equol as well as genistein via dihydrogenistein to 5-hydroxy-equol. Strain Mt1B8 was a gram-positive, rod-shaped bacterium identified as a member of the CORIOBACTERIACEAE: Strain Mt1B8 also transformed dihydrodaidzein and dihydrogenistein to equol and 5-hydroxy-equol, respectively. The conversion of daidzein, genistein, dihydrodaidzein, and dihydrogenistein in the stationary growth phase depended on preincubation with the corresponding isoflavonoid, indicating enzyme induction. Moreover, dihydrogenistein was transformed even more rapidly in the stationary phase when strain Mt1B8 was grown on either genistein or daidzein. Growing the cells on daidzein also enabled conversion of genistein. This suggests that the same enzymes are involved in the conversion of the two isoflavones.