Characterization of the components and metabolites of ethanol extracts of psoralea fructus in the plasma and tissues of rats based on ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry.

Psoralea fructus (PF) is a well-documented traditional Chinese medicinal herb with potent tonic effects and has been widely used in clinical practice for centuries. This study systematically characterized the in vivo metabolic profiles of the ethanol extract of Psoralea fructus (PFE) in Sprague-Dawley (SD) rats. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was used to identify both prototype components and metabolites in rat plasma and major organ tissues. First, we performed comprehensive chemical profiling of PFE using UPLC-QTOF-MS, which enabled the tentative identification of 132 chemical constituents. Following oral administration of PFE, we further characterized the systemically absorbed prototype components in plasma and various tissues. In total, 85 prototypical compounds were identified across all biological samples: 56 prototype compounds were identified in plasma, primarily consisting of coumarins, flavonoids, and phenolics. For major organs, 57, 71, 43, 36, 48, and 26 prototype compounds were found in the heart, liver, spleen, lung, kidney, and brain, respectively, with all tissues dominated by the same classes of chemical components. Subsequently, metabolite profiling was performed to elucidate the biotransformation characteristics of PFE. Metabolites were putatively annotated based on public databases and previously reported literature. A total of 83 metabolites were identified in plasma, and 63, 79, 54, 50, 59, and 21 metabolites were detected in the heart, liver, spleen, lung, kidney, and brain, respectively. The major metabolic pathways of PFE included Phase I reactions (oxidation, reduction, hydrolysis, and hydroxylation) and Phase II conjugation reactions (sulfation and glucuronidation). Consistent with the selective permeability of the blood-brain barrier, the brain tissue exhibited the lowest abundance of prototype components and metabolites. In conclusion, this systematic investigation of the in vivo metabolic characteristics of PFE provides a solid scientific foundation for guiding the rational clinical application of PF.