A step-by-step progressive strategy exploring whole metabolic profiles in vivo for Polygalae Radix with/without licorice.

Introduction: Polygalae Radix (PR) is known to relieve toxicity and increase efficiency in various diseases after processing. However, there were few studies for aromatic carboxylic acids (ACAs) due to the limited detection, especially for the metabolites within m/z 100-2000.

Objectives: This study aims to elucidate the whole metabolism of PR with/without licorice (LP), focusing on metabolites within m/z 100-2000 and pharmacodynamics in vivo.

Material and methods: This study was established by the combination of multidimensional ultra-high performance liquid chromatography coupled with a mass spectrometer (UPLC-MS) technology with protein sedimentation method to analyze metabolites in plasma, brain, colon, and stomach contents. Quantitative monitoring ACAs was enhanced with our novel stable isotope derivatization (SILD) technique. And then the pharmacokinetics (PK) study of relatively large metabolites was carried out. A targeted network pharmacology approach was established to avoid false positive results, mapping interactions relevant to Alzheimer's disease (AD), and other conditions.

Results: The 85 polygala metabolites were qualitatively analyzed in plasma, brain, colon, and stomach contents. The 11 types of relatively large metabolites and 8 types of ACAs were quantitatively monitored. Among them, nine types of relatively large metabolites were assessed through PK studies. In targeted network pharmacology, it highlighted the significance of small molecular metabolites, including ACAs et al, which were frequently overlooked. LP may play a more key role mainly through neural active ligand-receptor interaction, AD, and pertussis pathways. These findings have outlined a step-by-step strategy for in-depth research in vivo, laying a foundation for further verification of biological function.