Metabolite Profiling, Pharmacokinetics, and In Vitro Glucuronidation of Icaritin in Rats by Ultra-Performance Liquid Chromatography Coupled with Mass Spectrometry

Abstract

Icaritin is a naturally bioactive flavonoid with several significant effects. This study aimed to clarify the metabolite profiling, pharmacokinetics, and glucuronidation of icaritin in rats. An ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) assay was developed and validated for qualitative and quantitative analysis of icaritin. Glucuronidation rates were determined by incubating icaritin with uridine diphosphate glucuronic acid- (UDPGA-) supplemented microsomes. Kinetic parameters were derived by appropriate model fitting. A total of 30 metabolites were identified or tentatively characterized in rat biosamples based on retention times and characteristic fragmentations, following proposed metabolic pathway which was summarized. Additionally, the pharmacokinetics parameters were investigated after oral administration of icaritin. Moreover, icaritin glucuronidation in rat liver microsomes was efficient with CLint (the intrinsic clearance) values of 1.12 and 1.56 mL/min/mg for icaritin-3-O-glucuronide and icaritin-7-O-glucuronide, respectively. Similarly, the CLint values of icaritin-3-O-glucuronide and icaritin-7-O-glucuronide in rat intestine microsomes (RIM) were 1.45 and 0.86 mL/min/mg, respectively. Taken altogether, dehydrogenation at isopentenyl group and glycosylation and glucuronidation at the aglycone were main biotransformation process in vivo. The general tendency was that icaritin was transformed to glucuronide conjugates to be excreted from rat organism. In conclusion, these results would improve our understanding of metabolic fate of icaritin in vivo.

Characterization of the In Vivo and In Vitro Metabolites of Linarin in Rat Biosamples and Intestinal Flora Using Ultra-High Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Tandem Mass Spectrometry

“…Additionally, apigenin-xyloside was identified as one of the metabolites. Similar glycosylation metabolic pathways have also been reported in other flavonoids, such as icaritin [ 18 ]. It is believed that when catalyzed by glycosyltransferases, sugar residue can be transferred to nucleophilic glycosyl acceptor molecules, such as flavonoids, and that the sugar residues are usually derived from activated donors like sugar-nucleotide derivatives (UDP-Glc, UDP-Gal, UDP-GlcNAc, UDP-GalNAc, UDP-Xyl and UDP-GlcA) [ 19 ].…”

SAR Study on Estrogen Receptor α/β Activity of (Iso)flavonoids: Importance of Prenylation, C-Ring (Un)Saturation, and Hydroxyl Substituents

“…While DMI was only detected in traces in the hydrolyzed extract, ICT is metabolized by P450 enzymes to the estrogenic metabolite, DMI (Scheme 1, Figure 4C,D), in vivo. 43 The estrogenic results with E. sagittatum may mostly correlate with the effects observed with its weakly estrogenic major flavonol, ICT, and to a certain degree with its metabolite DMI. The present findings suggest that the estrogenic effects of the tested extracts could correlate with the order of activity of their corresponding bioactive (iso)flavonoids: in ERα: 8-PN/hops > 8-PA/inflata licorice ≈ GEN/red clover > DMI/E.…”

“…sagittatum was hydrolyzed prior to biological analysis yielding an extract enriched in aglycones, including the weakly estrogenic ICT (Figures , S4–S10). While DMI was only detected in traces in the hydrolyzed extract, ICT is metabolized by P450 enzymes to the estrogenic metabolite, DMI (Scheme , Figure C,D), in vivo . The estrogenic results with E.…”