Biotransformation of (-)-Epicatechin 3-O-Gallate by Human Intestinal Bacteria.

Isolation and Characterization of a Human Intestinal Bacterium <i>Eggerthella</i> sp. CAT-1 Capable of Cleaving the C-Ring of (+)-Catechin and (−)-Epicatechin, Followed by <i>p</i>-Dehydroxylation of the B-Ring

“…SDG-2 was isolated from human feces as a bacterium capable of catalyzing dehydroxylation of the p-hydroxyl groups of (+)-DHEND. 12) This strain also cleaved the Cring of (3R)-and (3S)-flavan-3-ols, 7) and showed a capability for p-dehydroxylation of a 3,4-dihydroxyphenyl moiety in the B-ring of (3R)-flavan-3-ols, but not of (3S)-flavan-3-ols (Fig. 5).…”

“…7) Furthermore, the cleavage of the C-ring is prerequisite for elimination of a p-hydroxyl group of the B-ring by Eg. sp.…”

“…2,4,5) When catechins are ingested, they inevitably come into contact with intestinal bacteria in the gastrointestinal tract and are converted to various metabolites, such as γ-valerolactones and simple phenolic acids. [6][7][8] Differences in bioconversion between diastereoisomers as substrates have been reported; for example, Eggerthella (Eg.) sp.…”

“…9) Previous studies showed that (+)-catechin and their gallate forms were transformed to p-dehydroxylated products after ring fission by incubation with a mixture of human intestinal bacteria. 7) Therefore, in the present study, we attempted to isolate human fecal bacteria that were capable of p-dehydroxylation of (2R)-1-(3,4-dihydroxyphenyl)-3-(2,4,6-triphydroxyphenyl) propan-2-ol (CAM1, Fig. 1).…”

Polyphenols in lahpet-so and two new catechin metabolites produced by anaerobic microbial fermentation of green tea

“…Compounds 4-6 were reported to be metabolites of catechins and proanthocyanidins produced by mammalian intestinal bacteria [6,7,11,12]. Pyrogallol (3) is considered to be produced by degradation of gallic acid [9,10], while the three diphenylpropane derivatives are reduction products of 2, 3, and (−)-epiafzelechin.…”