Anaerobic C-ring cleavage of genistein and daidzein by Eubacterium ramulus

Degradation of quercetin and luteolin by Eubacterium ramulus.

The degradation of the flavonol quercetin and the flavone luteolin by Eubacterium ramulus, a strict anaerobe of the human intestinal tract, was studied. Resting cells converted these flavonoids to 3,4-dihydroxyphenylacetic acid and 3-(3,4-dihydroxyphenyl)propionic acid, respectively. The conversion of quercetin was accompanied by the transient formation of two intermediates, one of which was id...

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 a...

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

Daidzein and genistein contents of vegetables.

Food samples (n 114) were prepared from vegetables commonly eaten in Europe. The glycosidic forms of the phyto-oestrogens daidzein and genistein were extracted from the dried foods into aqueous methanol. The isoflavones were quantified by GC-MS after hydrolytic removal of any conjugated carbohydrate. Completeness of extraction and any procedural losses of the isoflavones were accounted for usin...

C-ring cleavage of flavonoids by human intestinal bacteria.

Four hitherto undescribed Clostridium strains capable of cleaving the C ring of quercetin, kaempferol, and naringenin at C-3-C-4 were isolated from the fecal flora of humans. None of the strains cleaved catechin. C-ring fission occurred when the substrate was either in solution or in suspension. Mixed cultures of flavonoid-hydrolyzing bacteria, flavonoid-cleaving bacteria, and Escherichia coli,...