[Identification of chemical constituents and in vivo metabolites in rats of classic formula Baizhu San using UPLC-Q-Exactive-Orbitrap-MS].

This study employed ultra-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry(UPLC-Q-Exactive-Orbitrap-MS) to investigate the chemical constituents of the classic formula Baizhu San and their prototype components and metabolites in rats, aiming to elucidate the potential pharmacologically active substances of this formula. Following the final intragastric administration of Baizhu San, plasma, urine, and feces samples were collected from rats and analyzed in both positive and negative ion modes using Full MS-ddMS~2 scanning. The mass spectral data were processed using Xcalibur 4.5 and Compound Discoverer 3.3 software to identify the chemical constituents in Baizhu San and the prototype components and metabolites in the biological samples. A total of 125 constituents were identified in the Baizhu San extract, comprising 51 flavonoids, 44 triterpenoids, 9 lactones, 8 organic acids, 4 phenylpropanoids, and 9 other compounds. A total of 69 prototype components and 79 metabolites were identified in the rat biological samples, and the metabolic pathways involved phase I reactions such as deglycosylation, oxidation, and hydrolysis, as well as phase Ⅱ reactions including glucuronidation, sulfation, and glutathione conjugation. This study presents the first systematic characterization of the chemical constituents of Baizhu San and their absorption and metabolism characteristics in rats, offering an important reference for the investigation of the pharmacodynamically active substances and quality control of this formula.