Systematically characterization of in vivo substances of Ziziphi Spinosae Semen in rats by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry analysis

Ziziphi Spinosae Semen (ZSS), the seeds of Ziziphus jujuba var. spinosa, is widely used in China or other Asian countries for the treatment of insomnia and palpitation. In our previous work, chemical constituents in ZSS were profiled by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF MS). Notably, characterization of substances in vivo was of great importance to reveal the therapy basis or mechanism in further work. Till now, there were few reports about in vivo substances’ investigation of ZSS. In the present study, an integrated strategy contained represented compounds and diagnostic ions extraction was applied to characterize metabolism feature of ZSS in rats based on UHPLC/Q-TOF MS method. First, the metabolic information of four compounds (spinosin, isovitexin, jujuboside B, betulinic acid) featuring three representative chemical structures (flavonoids, saponins, terpenes) in ZSS was conducted, and their metabolism features were summarized, especially for flavonoid C-glycosides. Second, the absorbed compounds and representative compounds-related metabolites were quickly screened out; during this time, the diagnostic ions were sorted out. Last, with the help of diagnostic ions and summarized metabolic reactions, other metabolites were characterized. As a result, a total of 151 xenobiotics (58 prototypes and 93 metabolites) were identified or tentatively characterized in rats after ingestion of ZSS. Among them, 16 substances were presented in plasma, 114 in urine, 51 in bile, and 120 in feces, respectively. Hydrogenation, hydrolysis, and glucuronidation were the major metabolic reactions of ZSS in rats. The present study provided meaningful data for further pharmacological mechanism research or pharmacokinetics evaluation of ZSS.