Characterization of deglycosylated metabolites of platycosides reveals their biotransformation after oral administration

Abstract

Platycodon grandiflorus is a well-known edible and medicinal plant that has been developed for dietary supplements or functional foods to relieve pulmonary disorders. Platycosides are the main active constituents of P. grandiflorus with multiple pharmacological activities. However, their metabolic fates after dietary consumption are still unclear. Herein, 25 deglycosylated metabolites of platycosides were identified, most of which were identified in vivo for the first time. Notably, 3-O-β-d-glucopyranosyl platycosides could be absorbed into the bloodstream, and their structures were unambiguously characterized with the aid of chemically prepared standards, including two new compounds (M3 and M11). These findings reveal that both intestinal bacterial metabolism and hydrolysis of ester linkage at C-28 by carboxylesterases in liver are the possible in vivo deglycosylation metabolism pathway of platycosides. This study greatly facilitated our understanding of the fate of the platycosides after dietary consumption of P. grandiflorus products.