In vitro human intestinal microbiota biotransformation of nobiletin using liquid chromatography-mass spectrometry...

In this study, the in vitro biotransformation of nobiletin by human intestinal microbiota, which is a bioactive polymethoxyflavone widely presented in Citrus plants, has been investigated via utilizing an anaerobic incubation protocol. The incubation samples were detected using high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. A background subtraction strategy incorporated in Microsoft Office was employed to eliminate the interferences in medium and feces. The parent and three metabolites sinensetin, 5-hydroxy-6,7,3',4'-tetramethoxyflavone, and 5-demethylnobiletin were detected and identified based on the characteristics of their protonated molecules. The proposed metabolic pathway revealed that nobiletin went through phase I metabolism including demethylation and demethoxylation in human intestinal microbiota. The characterization of nobiletin metabolic profile transformed by human intestinal bacteria would be helpful for understanding its efficacy and action mechanism.