Chemical composition and spatiotemporal distribution characteristics of Gu-ben-Qing-Hua formula in ulcerative colitis rats based on UPLC-Q-Exactive-MS and MALDI mass spectrometry imaging.

Gu-Ben-Qing-Hua formula (GBQHF) is a traditional Chinese medicine (TCM) formula that exhibits significant efficacy in the treatment of ulcerative colitis (UC) in a clinical setting. A combination of ultrahigh-performance liquid chromatography with Q Exactive mass spectrometry (UPLC-Q-Exactive-MS) in both positive and negative ionization modes and matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) in positive ionization mode was used to identify the components of GBQHF and determine its distribution after oral administration. A total of 240 chemical compounds, including 100 flavonoids, 27 saponins, 22 terpenoids, 20 phenolics, 18 alkaloids, 17 volatile compounds, and 12 organic acids, and 24 other compounds, were identified in GBQHF with high mass accuracy (within 5 ppm) and using MS/MS data based on online, local, and self-built databases for GBQHF using UPLC-Q-Exactive-MS. Moreover, 67 prototype compounds were identified in the intestinal tissues. The characteristics of the identified compounds, including the numbers as well as the structure and source in the duodenum, ileum, proximal colon, and distal colon, were elucidated. Among these 67 compounds, the distribution of licoricesaponin A3 and astragaloside IV known for their anti-inflammatory properties was analyzed using MALDI-MSI in 1.5-, 6-, and 24-h postdose sections of the ileum and the proximal and distal colon. Licoricesaponin A3 was significantly distributed in the basolateral region of the proximal colon, especially at 1.5 h. Astragaloside IV showed a significant distribution both in the mucosal side and basolateral region of the distal colon, especially at 6 after administration. This study systematically and comprehensively characterizes the chemical constituents of GBQHF, thereby establishing an effective strategy to characterize compounds in TCM formulae used to treat UC.