Metabolism profiles of icariin in rats using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry and in vitro enzymatic study.
Icariin (ICA), the major constituent of Epimedium brevicornu Maxim, is recognized as an effective agent for the treatment of osteoporosis. In our previous report, the relatively short half-life (74min) and poor bioavailability (approximately 0.1%) of ICA in rats suggested that not only ICA itself but also its metabolites could be responsible for the observed osteoporosis treatment effect. Therefore, the present study aimed at identifying the metabolites of ICA in rat plasma, bile, urine, and feces after the administration of a single oral dose of ICA (150mg/kg). In this work, ultra-high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS) method was established to identify the metabolic profiles following intragastric administration of pure ICA in rats. The blood, bile, urine, and feces samples of the rats were investigated to explore the complete metabolic pathway of ICA in vivo. A total of 14 metabolites were detected in the bile, revealing that the bile is the main excretion pathway for ICA and its metabolites. The conjugated metabolites as observed in vivo, was further confirmed by the in vitro enzymatic study. Five metabolites of ICA, including demethylicariin, icariside I-3-O-glucuronide, demethylicariside II, demethylicariside II-7-O-glucuronide, and dehydroxyicaritin-glucuronide, were reported for the first time in the literature. In addition, the results revealed that the principal metabolism pathways of ICA in rat were deglycosylation and glucuronidation after deglycosylation.
Experiment Center for Teaching and Learning, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China; School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China.
Tao
T
Cheng
Experiment Center for Teaching and Learning, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China; School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China.
Tingting
T
Sheng
Experiment Center for Teaching and Learning, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China; School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China.
Yaxiong
Y
Yi
Experiment Center for Teaching and Learning, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China; School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China. Electronic address: zhangtdmj@hotmail.com.
Tong
T
Zhang
Experiment Center for Teaching and Learning, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China. Electronic address: pashanhan@126.com.
Han
H
Han
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism*; D005966:Glucuronidase / Q000378:metabolism*; D008297:Male; D053858:Metabolic Networks and Pathways; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D008970:Molecular Weight; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors
D005419:Flavonoids; D005966:Glucuronidase; C056599:icariin
Enzymatic study; Icariin; Metabolite characterization; Rats; UHPLC/QTOF-MS