Flavanol monomer-induced changes to the human faecal microflora

• Published in: British journal of nutrition Vol. 99; no. 4; pp. 782 - 792
• Main Authors: Tzounis, Xenofon, Vulevic, Jelena, Kuhnle, Gunter G. C., George, Trevor, Leonczak, Jadwiga, Gibson, Glenn R., Kwik-Uribe, Catherine, Spencer, Jeremy P. E.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.04.2008
• Subjects: Antioxidants; Antioxidants - metabolism; Antioxidants - pharmacology; Bacteria; Bacteria - drug effects; Bacteria - metabolism; Bacteriological Techniques; batch fermentation; Bifidobacterium; Bifidobacterium - growth & development; Biological and medical sciences; Carbon sources; catechin; Catechin - metabolism; Catechin - pharmacology; Clostridium; Clostridium - growth & development; colon; Colorectal cancer; drug effects; E coli; Energy sources; Environmental conditions; epicatechin; Escherichia coli; Escherichia coli - growth & development; Eubacterium; Eubacterium - growth & development; Faecal microflora; feces; Feces - microbiology; Feeding. Feeding behavior; Fermentation; Flavanols; Flavonoids; Flavonoids - metabolism; Flavonoids - pharmacology; fructooligosaccharides; Fundamental and applied biological sciences. Psychology; growth & development; Human subjects; Humans; Inflammatory bowel disease; Intestine, Large; Intestine, Large - metabolism; Intestine, Large - microbiology; Large intestine; Membrane filters; Metabolism; Metabolites; microbiology; microorganisms; Nutrition research; pharmacology; Prebiotics; Studies; sucrose; Trust funds; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Flavanols; Faecal microflora; Large intestine; Prebiotics; Flavanol; Human; Vertebrata; Mammalia; Digestive system; Gut; Microflora; Change; Feces; Flavanols: Prebiotics: Faecal microflora: Large intestine
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114507853384

We have investigated the bacterial-dependent metabolism of ( − )-epicatechin and (+)-catechin using a pH-controlled, stirred, batch-culture fermentation system reflective of the distal region of the human large intestine. Incubation of ( − )-epicatechin or (+)-catechin (150 mg/l or 1000 mg/l) with faecal bacteria, led to the generation of 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone, 5-phenyl-γ-valerolactone and phenylpropionic acid. However, the formation of these metabolites from (+)-catechin required its initial conversion to (+)-epicatechin. The metabolism of both flavanols occurred in the presence of favourable carbon sources, notably sucrose and the prebiotic fructo-oligosaccharides, indicating that bacterial utilisation of flavanols also occurs when preferential energy sources are available. (+)-Catechin incubation affected the growth of select microflora, resulting in a statistically significant increase in the growth of the Clostridium coccoides–Eubacterium rectale group, Bifidobacterium spp. and Escherichia coli, as well as a significant inhibitory effect on the growth of the C. histolyticum group. In contrast, the effect of ( − )-epicatechin was less profound, only significantly increasing the growth of the C. coccoides–Eubacterium rectale group. These potential prebiotic effects for both (+)-catechin and ( − )-epicatechin were most notable at the lower concentration of 150 mg/l. As both ( − )-epicatechin and (+)-catechin were converted to the same metabolites, the more dramatic change in the growth of distinct microfloral populations produced by (+)-catechin incubation may be linked to the bacterial conversion of (+)-catechin to (+)-epicatechin. Together these data suggest that the consumption of flavanol-rich foods may support gut health through their ability to exert prebiotic actions.