A comparative study of Liandan Xiaoyan Formula metabolic profiles in control and colitis rats by UPLC-Q-TOF-MS combined with chemometrics

Liandan Xiaoyan Formula (LDXYF) is a traditional Chinese medicine prescription (TCMP) consisting of Herba Andrographis (dried herb of Andrographis paniculata) and Picrasmae ramulus et folium (dried twiggeries and leaves of Picrasma quassioides). It is used to treat diarrhea, acute gastroenteritis, colitis, and dysentery, among other inflammatory gastrointestinal diseases. However, because of less research on the in vitro chemical composition and holistic metabolism of LDXYF, in vivo mechanisms of action and quality control of LDXYF have not yet been fully assessed due to the lack of studies into its bioactive components. In this study, ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was established for comprehensive analysis of chemical compounds of LDXYF and their metabolites in serum and urine samples of control and colitis rats. As a result, totally 94 compounds in LDXYF were unambiguously identified or tentatively characterized. And a total of 91 LDXYF-related xenobiotics were characterized, including 61 (16 prototypes and 45 metabolites) in serum, and 72 (26 prototypes and 46 metabolites) in urine. Besides, we compared the exposure of metabolites in normal and colitis rats by chemometrics and summarize similarities and differences of metabolic pathways of mainly compounds in normal and colitis conditions, and found that in control and colitis conditions, alkaloids predominantly went through phase I reaction combined phase II reaction (hydroxylation and sulfation, hydroxylation and glucuronidation, demethylation and glucuronidation), while the major metabolic reaction of diterpene lactones were phase Ⅱ reactions (glucuronidation, sulfation). And there were no significant differences in metabolic pathways between control and colitis groups, just the exposure of prototype and their metabolites absorbed into serum or excreted through the urine were different, and 17 alkaloids and 6 diterpene lactone prototypes and their metabolites in serum could be considered as potential pharmacodynamic substances. A comprehensive analysis of the compounds and metabolic characteristics of LDXYF was conducted in our study, and the results laid the chemical foundation for further research into effective substances and the action mechanism of LDXYF.