Identification of absorbed components and metabolites of Zhi-Zi-Hou-Po decoction in rat plasma after oral administration by an untargeted metabolomics-driven strategy based on LC-MS

In this study, a novel untargeted metabolomics-driven strategy based on LC-MS was used to rapidly screen and identify the absorbed components and metabolites of Zhi-Zi-Hou-Po decoction (ZZHPD) in rat plasma. The plasma sample was obtained from orbital venous of rats after oral administration and pretreated by protein precipitation before analysis. All sample data from total ion chromatograms (TICs) of LC-TOF/MS were aligned and peak picked by XCMS and MetAlign combined to extract three-dimensional datasets (peak code, tR–m/z pairs and ion intensity). Xenobiotics in rat plasma were differentiated from endogenous components by multivariate statistical analysis and then divided into prototype compounds and metabolites by comparing tR–m/z with the chemical compounds of ZZHPD. Combined with fragment ions and structure information of LC-TSQ/MS, a total of 61 compounds, including 35 prototype compounds and 26 metabolites, were rapidly identified or tentatively characterized in rat plasma. Results indicated that iridoid glycosides, monoterpenoids, flavonoids, and lignans were the main absorbed chemical components of ZZHPD. Glucuronidation and sulfation were the main metabolic pathways of ZZHPD compounds in vivo. In addition, there were ring-opening reactions and reduction reactions for iridoid glycosides, hydrolysis for flavonoids, as well as hydroxylation and stereoscopic conversion reactions for lignans. This study offers a systematically applicable approach for rapid screening and identification of xenobiotics and metabolites derived from multi-herb prescription in vivo, and provides useful information for ascertaining bioactive ingredients and action mechanisms of ZZHPD.