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Updated: Sep 12, 2026

Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade
Published on: August 14, 2019
C-ring cleavage of flavonoids by human intestinal bacteria
J Winter1, L H Moore, V R Dowell
1Department of Pathology, St. Luke's-Roosevelt Hospital Center, New York, New York 10025.
Abstract:
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, which was used to provide the anaerobic environment, rapidly metabolized rutin to 3,4-dihydroxyphenylacetic acid, indicating that the intestinal half-life of the biologically active aglycone is short. The cleaving strains shared many phenotypic characteristics, including their inability to ferment sugars, but they differed sufficiently to indicate that they represent different species.
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