Characterization of the Constituents of the Stem of Bauhinia championii (Benth.) Benth and Their Metabolites in Rat Plasma by UPLC‐LTQ/Orbitrap HRMS

ABSTRACT Rationale Stems of Bauhinia championii (Benth.) Benth (Longxuteng in Chinese, LXT) are widely used folkloric traditional medicine in China, which is mainly utilized to treat rheumatoid arthritis, epigastric pain, and traumatic injury. Nevertheless, the comprehensive components correlated to the therapeutic efficacy are still unclear. Our study aims to characterize constituents in LXT extract and their metabolites in plasma and subsequently provide detailed compositional information for the LXT's quality evaluation and mechanism researches. Methods Ultraperformance Liquid Chromatography–Orbitrap Elite Combined High Resolution Mass Spectrometer (UPLC‐LTQ/Orbitrap HRMS) was used to identify the constituents of LXT and their metabolites in plasma. The HRMS data were analyzed by Xcalibur, and the constituents were identified by the MS 2 profile, characteristic fragments, and cleavage patterns by comparative analysis using authentic standards, online mass spectral libraries, and literature reports. Results Forty‐six components in LXT extract were identified, including 28 flavonoids, 5 phenylpropanoids, 10 organic acids, 1 carbohydrate, 1 nucleoside, and 1 alkaloid. Among them, 27 components were detected from LXT for the first time. Meanwhile, 54 compounds were found in plasma, including 11 prototypes and 43 metabolites. The prototypes, which are mainly polymethoxyflavones, dihydroflavonol glycosides, and flavanols, seem to be potential pharmacodynamic components of LXT. Conclusion This is the first report on the comprehensive component identification of LXT extract and its metabolites in plasma by using LC‐MS. Our findings may serve as a theoretical basis for LXT's quality evaluation and mechanism research.