Bupleurum scorzonerifolium: Systematic research through pharmacodynamics and serum pharmacochemistry on screening antidepressant Q-markers for quality control

Bupleurum scorzonerifolium (BS) is one of the sources of Bupleuri Radix, which was first recorded in Shennong's classic of materia medica. It has a medicinal history of 2000 years and is now widely used for the treatment of depression clinically. However, the material basis of antidepressant effects is unclear, and the quality evaluation method is lacking. The paper aims to investigate the antidepressant quality markers (Q-markers) of BS by electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS). Firstly, the rat depression model was established by using chronic unpredictable mild stress (CUMS) combined with the solitary confinement method to evaluate the pharmacodynamics of BS. After verification of the antidepressant effect of BS, UPLC-ESI-Q-TOF-MS was used to analyze BS and the blood components of BS. A total of 34 components were identified in BS, in which 8 components, including saikosaponin a (SSa), saikosaponin c (SSc), saikosaponin d (SSd), saikosaponin b1 (SSb1), saikosaponin b2 (SSb2), glycyrrhetinic acid, nootkatone and valerenic acid, were detected in serum. SSa, SSc, SSd, SSb1 and SSb2 were found as metabolites, and glycyrrhetinic acid, nootkatone and valerenic Acid were identified as the prototypes in the blood. The depression model of zebrafish was established with reserpine to verify the antidepressant effect of the potential eight active components. The results showed that all these components could markedly improve the depressive behavior of zebrafish, increase the content of 5-HT and reduce the cortisol content. Finally, according to the principles of effectiveness, accessibility and measurability for Q-markers, SSa, SSc, and SSd were confirmed as Q-markers of BS, and the contents of 3 Q-markers in 10 batches of BS from different origins were determined to be 0.0728-1.465%. In addition, the total contents of 3 Q-markers in BS produced in Lindian, Heilongjiang Province, were higher than those in other origins. This paper provided a reliable method for the quality evaluation of BS for depression treatment.