Abstract
Quercetin, a polyphenol antioxidant, is widely distributedin foodin the form of glycoside rutin, which is not readily absorbed in thegastrointestinal tract. The microbiota of the colon is known to biotransformrutin, generating quercetin aglycones that can be absorbed. We investigatedthe role of the ileal and colonic microbiota in rutin biotransformationusing established in vitro fermentation models. Overall, a higherrate of rutin biotransformation was observed during colonic fermentationcompared with ileal fermentation. The colonic microbiome showed higherpotential for rutin conversion to quercetin through an increased abundanceof & alpha;-rhamnosidase- and & beta;-glucosidase-encoding genes comparedto the ileal microbiome. Nonetheless, rutin metabolism occurred rapidlyduring ileal fermentation (& SIM;20% rutin disappearance after 1h). The appearance of quercetin varied depending on the ileal inoculumand correlated with an increased abundance of Firmicutes, suggestingthat quercetin absorption could be improved via modulation of theileal microbiota.