**3.2 Metabolism in the colon**

Microbes break down the flavonoid fragment, splitting the flavonoid core, i.e., heterocyclic oxygen-containing ring, and the breakdown products are detected in urine and plasma. Several hydroxylated phenyl carboxylic acids are among them. Flavonols are broken down into phenylacetic acids and phenyl propionic acids. However, the effects of these phenyl propionic acids have yet to be proven in humans [18, 19]. In bodily tissues, these phenyl carboxylic acids are extra degraded by bacteria and transformed by enzymes. The phenyl propionic acids will be oxidized to benzoic acids as a result. Although roughly 60 possible phenolic acid metabolites were recognized and measured, only a small amount of phenolic acids were discovered. Hippuric acid, the glycine ester of benzoic acid, was an actual significant metabolite in people who had subsequent tea consumption [19, 20]. Microorganisms in the colon have been found to show an imperative role in the conversion of flavonoids to phenolic acids. Colonic bacteria generate glucuronidases, glycosidases, and sulfatases, which can shred flavonoid conjugates of their sugar moieties, glucuronic acids, and sulfates, in addition to the destruction of the flavonoid ring structure O-glycosides and C-glycosides that could be hydrolyzed by human gut bacteria [21].
