Phytochemical basis and mechanistic insight of Swertia macrosperma in treating 5-fluorouracil-induced diarrhea.
ETHNOPHARMACOLOGICAL RELEVANCE 5-Fluorouracil (5-FU)-induced diarrhea severely impacts chemotherapy outcomes. Swertia macrosperma (C. B. Clarke) C. B. Clarke in Hook. f. is traditionally used for diarrhea, yet its efficacy and mechanism remain unclear. AIM OF THE STUDY This study first investigated the anti-diarrheal potential of 70% ethanol extract from S. macrosperma (SME). MATERIALS AND METHODS In a 5-FU-induced mouse model, SME was evaluated for its effects on diarrhea severity, weight loss, intestinal histopathology, oxidative stress (MDA, SOD, GSH), inflammation (TNF-α, IL-6, COX-2, iNOS), and tight junction proteins (Claudin-1, Occludin). Phytochemical investigation (including isolation, structural elucidation, and UPLC-MS quantification), IEC-6 cell-based mechanistic studies, network pharmacology, and Western blot analysis (for PI3K-AKT pathway) were performed. RESULTS SME significantly alleviated weight loss, diarrhea severity, and intestinal histopathological damage. It inhibited oxidative stress and inflammation while upregulating tight junction proteins, thereby protecting intestinal barrier integrity. Phytochemical investigation yielded 57 compounds, including three new isolates (swemacronosides A-C) and 37 first-time reports for this species. UPLC-MS quantification identified compounds 7, 8, and 23 as the predominant constituents. Mechanistic studies indicated that SME ameliorated diarrhea symptoms in mice via the PI3K-AKT signaling pathway. Western blot confirmed that compounds 7 and 23 significantly restored the 5-FU-induced downregulation of PI3K expression and the p-AKT/AKT ratio. CONCLUSION S. macrosperma ameliorates 5-FU-induced diarrhea, and the mechanism potentially involves the PI3K-AKT pathway. However, under the present experimental conditions, it did not significantly reverse 5-FU-induced thymic and splenic atrophy. These findings provide a scientific basis for clinical application and offer potential chemical markers for future quality control studies of S. macrosperma.