The Heterocyclic Ring Fission and Dehydroxylation of Catechins and Related Compounds by Eubacterium sp. Strain SDG-2, a Human Intestinal Bacterium.

Bioconversion of (−)-Epicatechin, (+)-Epicatechin, (−)-Catechin, and (+)-Catechin by (−)-Epigallocatechin-Metabolizing Bacteria

“…On the basis of these results together with previous reports, [11][12][13] we propose the bioconversion of catechol-type catechins by intestinal bacteria as illustrated in Fig. 4.…”

“…These observations seemed to indicate that the presence of three vicinal hydroxyl groups in the B ring is important for the dehydroxylation by A. equolifaciens MT4s-5. Wang et al 11) reported that Eggerthella sp. SDG-2 (formerly Eubacterium sp.…”

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

“…In the mechanism, degradation of the phloroglucinol ring is the inverse of the biosynthesis of the flavan-3-ol A ring, and it is closely related to the production metabolism of hydroxyphenyl-4-hydroxypentanoic acids (10 and 11) and 6 hydroxyphenyl-γ-valerolactones (12 and 13), which are major catechin metabolites produced by mammalian intestinal bacteria [6][7][8] and were not detected in this experiment. The metabolites 12 and 13 are produced by removal of 2 acetic acid units from 4 and 5 via intermediates 4a,b and 5a,b.…”

“…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.…”

“…However, the bioavailability of tea catechins from the digestive tract is low [4,5]. Therefore, it has been suggested that catechin degradation products generated by intestinal bacteria are important in the biological activity of green tea [6][7][8]. Recently, we reported that Japanese postfermented tea produced by anaerobic microbial fermentation of green tea contained polyphenols identical to the tea catechin metabolites formed by mammalian intestinal bacteria [9].…”