Characterization of chemical constituents and identification of absorbed components and metabolites in rat plasma of Fu‐Ke‐Zai‐Zao pills by ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry

Fu-Ke-Zai-Zao pills, the famous traditional Chinese medicine formula, composed of 42 medicinal herbs, have been widely used to treat various gynecological diseases. However, the chemical constituents and metabolic profiling of Fu-Ke-Zai-Zao pills remain largely unknown, which hampers improvement of the quality control and pharmacological elucidation of this formula. In the present study, a sensitive and selective ultra high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry method was developed to separate and identify the comprehensive chemical constituents of Fu-Ke-Zai-Zao pills. According to the results, a total of 83 compounds were identified, including phenylpropionic acids, flavonoids, terpenoids, triterpene saponins, and phthalides, and 81 compounds were first reported in Fu-Ke-Zai-Zao pills. Moreover, the absorbed components and metabolites in rat plasma after intragastric administration of Fu-Ke-Zai-Zao pills were also detected by the same analytical method. A total of 36 compounds were identified, including 21 prototypes and 15 metabolites. The latter were generated through the metabolic pathways of methylation and glucuronidation, and glucuronidated metabolites were the main constituents in the plasma. This is the first systematic study on the chemical constituents and metabolic profiling of Fu-Ke-Zai-Zao pills, and the results provide valuable chemical information for further elucidating pharmacological effects and mechanism of action of Fu-Ke-Zai-Zao pills.