Pharmacokinetic study of rutin and quercetin in rats after oral administration of total flavones of mulberry leaf extract

Mulberry leaves, a traditional Chinese medicine, are effective in the treatment of diabetes mellitus. Rutin and quercetin are the main components of total flavones of mulberry leaf extract. To study the pharmacokinetics of rutin and quercetin in rat plasma and their metabolites in rat urine and feces after oral administration of total flavones of mulberry leaf extract. At different timepoints after oral administration of total flavones of mulberry leaf extract in rats, plasma concentrations of rutin and quercetin were determined by RP-HPLC. The main pharmacokinetic parameters were estimated using 3P97 software. The metabolites in rat urine and feces were determined by using UPLC-ESI-QTOF/MS and estimated MetaboLynx™ software. The plasma concentration-time curves of rutin and quercetin both were best fitted with a two-compartment model. Rutin and quercetin were absorbed rapidly and then slowly decreased. Two prototype compounds and seven metabolites were identified. The pharmacokinetic and metabolic results may be useful for further studies of the bioactive mechanism of mulberry leaf flavones and potential development of a new TCM.