Identification of Plasma Absorbed Components of Qingxin Zishen Prescription by UPLC-Q-TOF MS

It has been confirmed in clinic that Qingxin Zishen Prescription (QZP) is effective and safe in relieving vasomotor symptoms. However, its active components have not been elucidated. In this study, a method based on ultra-performance liquid chromatography quadrupole-time of flight mass spectrometry (UPLC-Q-TOF MS) was developed to identify the plasma absorbed components of QZP. After continuous intragastric administration of 48.5 g/kg QZP for 3 days to female SD rats, plasma samples were collected and then pre-treated by solid phase extraction (SPE) to remove proteins in plasma. Then, chromatographic separation of the plasma samples was performed on an Agilent ZORBAX SB C18 column (4.6 mm×100 mm, 1.8 µm) using a gradient elution with a mobile phase composed of 0.1% formic acid aqueous solution (A) and methanol-acetonitrile (1:1, V/V, B) prior to MS analysis. The column temperature was kept at 40 ℃. The MS and MS2 analysis were performed with the electrospray ionization (ESI) source under both positive and negative ion modes from m/z 100 to 1300. Intelligent dynamic background deduction, information dependent acquisition and highly sensitive mode were used to collect the data. According to the accurate m/z values of MS and MS2 information, data from reference substance and related literature, the absorbed components in plasma were identified. In total, forty prototypes from QZP are identified and inferred in the plasma samples, including 27 alkaloids, 9 iridoid glycosides, 2 flavonoid carbon glycosides, 1 phenolic acid and 1 fatty acid. Among them, alkaloids are mainly from Nelumbo nucifera Gaertn, Coptis chinensis Franch, Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chou, and Uncaria rhynchophylla (Miq.) Miq. ex Havil. Iridoid glycosides are mainly from Rehmannia glutinosa Libosch. and Cornus officinalis Sieb. et Zucc. Furthermore, the fragmentation pathways and characteristic fragment ions of iridoid glycosides and dibenzylisoquinoline alkaloids were summarized. This study provides not only a rapid and comprehensive analysis method for the plasma absorbed components of QZP, but also a scientific fundamental for elucidating the material basis of action of QZP.