Anaerobic transformation of quercetin-3-glucoside by bacteria from the human intestinal tract

Citation
H. Schneider et al., Anaerobic transformation of quercetin-3-glucoside by bacteria from the human intestinal tract, ARCH MICROB, 171(2), 1999, pp. 81-91
Citations number
52
Categorie Soggetti
Microbiology
Journal title
ARCHIVES OF MICROBIOLOGY
ISSN journal
03028933 → ACNP
Volume
171
Issue
2
Year of publication
1999
Pages
81 - 91
Database
ISI
SICI code
0302-8933(199901)171:2<81:ATOQBB>2.0.ZU;2-H
Abstract
From human feces two phenotypically differ ent types of bacteria were isola ted on quercetin-3-glucoside as carbon and energy source. Isolates of one t ype were identified as strains of Enterococcus casseliflavus. They utilized the sugar moiety of the glycoside, but did not degrade the aglycon further . The sugar moiety (4 mM) was fermented to 5.5 +/- 2.1 mM formate, 2.1 +/- 0.7 mM acetate, 1.6 +/- 0.3 mM L-lactate, and 1.3 +/- 0.4 mM ethanol. The s econd type of isolate was identified as Eubacterium ramulus. This organism was capable of degrading the aromatic ring system. Growing cultures of Euba cterium ramulus converted 5 mM quercetin-3-glucoside to 1.7 +/- 0.6 mM 3,4- dihydroxyphenylacetic acid, 7.6 +/- 1.0 mM acetate, and 4.0 +/- 0.4 mM buty rate. Molecular hydrogen, 3,4-dihydroxybenzaldehyde, and ethanol were detec ted in small amounts. Phloroglucinol was a transient intermediate in the br eakdown of quercetin-3-glucoside. Eubacterium ramulus did nor grow on the a glycon quercetin or the ring-fission intermediate phloroglucinol, but cleav ed the flavonoid ring system when glucose was present as a cosubstrate. The most probable number of quercetin-3-glucoside-degrading bacteria determine d in nine human fecal samples was 10(7)-10(9)/g dry mass. Isolates from the se experiments were all identified as Eubacterium ramulus.