Analysis of gut microbiota metabolites of platycodin D and activity verification.

As the main saponin component of Platycodon grandiflorum A.DC, Platycodin D has been reported to have an anti-obesity effect. Due to poor oral absorption, the intestinal microflora usually transforms saponins into potential bioactive substances. In this study, we profiled the metabolic changes of platycodin D by incubating it with intestinal microflora extracted from mice feces subjected to either a standard control diet or a high-fat diet. A UPLC-LTQ-Orbitrap-MS method was used for rapid analysis of the metabolic profile of platycodin D. A total of 10 compounds were identified 9 of which were assessed to be metabolized by intestinal microflora. Dehydroxylation and deglycosylation were the major metabolic process of platycodin D. The metabolic profile of platycodin D biotransformed by intestinal microflora was elucidated based on the metabolite information. Platycodin D and its metabolites had anti-inflammatory effects in LPS-stimulated RAW 264.7 cells. Only platycodin D could alleviate lipid accumulation in FFA-treated HepG2 cells.