Rapid screening and identification of metabolites of quercitrin produced by the human intestinal bacteria using ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry

Ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF MS) technique combined with Metabolynx™ software was used for analysis of the metabolites of quercitrin by the isolated human intestinal bacteria from the human feces. Four metabolites of quercitrin were detected and tentatively identified based on the characteristics of their protonated ions. The metabolites were metabolized by four main metabolic pathways including hydroxylation, demethylation, deglycosylation and ring-cleavage. Quercitrin was metabolized to the hydroxyquercitrin and desmethylquercitrin by the majority of the isolated intestinal bacteria such as Bacteroides sp. 54, and was degraded to the deglycosylated product quercetin by rhamnosidase and further ring-cleavage metabolite 3,4-dihydroxybenzoic acid by the minority of the isolated bacteria such as Bacteroides sp. 45. The metabolic pathways and most of the metabolites of quercitrin were reported for the first time.