Conversion of daidzein and genistein by an anaerobic bacterium newly isolated from the mouse intestine.
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.
Department of Gastrointestinal Microbiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany.
Anastasia
A
Matthies
Thomas
T
Clavel
Michael
M
Gütschow
Wolfram
W
Engst
Dirk
D
Haller
Michael
M
Blaut
Annett
A
Braune
D000818:Animals; D001421:Bacteria, Anaerobic / Q000302:isolation & purification / Q000378:metabolism*; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D005260:Female; D019833:Genistein / Q000378:metabolism*; D006094:Gram-Positive Bacteria / Q000302:isolation & purification / Q000378:metabolism*; D007082:Ileum / Q000382:microbiology*; D007529:Isoflavones / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D021241:Spectrometry, Mass, Electrospray Ionization
D007529:Isoflavones; C013908:daidzin; D019833:Genistein