Identification of Icaritin Metabolites in Rats by LC-MS/MS

Abstract Objective Icaritin is the main aglycone and also active intestinal metabolite of prenylflavonoids from the Chinese materia medica Epimedii Herba. Modern pharmacological studies have demonstrated that icaritin has a wide range of biological activities. However, its metabolites and biotransformation pathways have not yet been comprehensively investigated. The present study aims to identify icaritin metabolites in rats by using a sensitive and effective LC-MS/MS method. Methods The plasma and urine samples of rats were collected before (blank) and after oral administration of icaritin, and subjected to liquid-liquid extraction with ethyl acetate. The full-scan LC-MS chromatograms of the plasma and urine samples were compared with those of blank samples to detect the possible metabolites, which were later detected by their product ion spectra. Results A total of 23 metabolites were identified, and conjugated icaritins produced by glucuronidation, glycosylation, and sulfation were its major metabolites. Minor demethylation, hydrogenation, and oxidation metabolites were also found. Conclusion Phase II metabolism is the main metabolic pathway of icaritin.