Identification and characterization of chemical constituents in Qi-Lin pills and their metabolites in rat bio-samples after oral administration using ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

Qi-Lin pill (QLP), a traditional Chinese medicine prescription (TCMP), composed of fifteen herbal medicines, has been widely used for the treatment of male infertility. However, an in-depth understanding of the chemical constituents of QLP and its in vivo metabolic study is lacking. In this study, a method using ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was established for comprehensive analysis of chemical constituents of QLP and their metabolites in plasma, urine, bile and feces after gastric perfusion. The method guaranteed the fast discovery of representative structural fragment information and provided efficient structure clues for identification based on data from MS mode. As a result, a total of 202 constituents were unambiguously identified or tentatively characterized. In addition, a total of 203 QLP-related xenobiotics were characterized, including 41 (22 prototypes and 19 metabolites) in plasma, 144 (47 prototypes and 97 metabolites) in urine, 50 (27 prototypes and 23 metabolites) in bile and 68 (51 prototypes and 17 metabolites) in feces. The metabolism reactions included phase I reactions (demethylation, hydroxylation, deglycosylation, deoxygenation, hydrogenation, dehydration, oxidation and hydrolysis) and phase II reactions (methylation, conjugation with glucuronide and sulfate). This was the first comprehensive investigation on chemical constituents and metabolic profiles of QLP in vivo, and the results provided chemical foundation for further research on effective substances and action mechanism of QLP.