Astilbin inhibits intestinal polyps via modulating the intestinal barrier, gut microbiota, and the intestinal inflammatory environment in mice.

[BACKGROUND] Astilbin (AST) has been showed to alleviate enteritis, but its effects on intestinal polyps, a precursor to colorectal cancer, remain unclear.

[PURPOSE] This study aimed to investigate the impact of AST on intestinal polyp formation and its underlying mechanisms.

[METHODS] In vivo, the Apc mouse model of familial adenomatous polyposis and the AOM/DSS-induced inflammatory adenomatous polyp model were used to assess AST's effects. In vitro, the protective effects of AST on the intestinal barrier were evaluated using immunofluorescence and Caco-2 monolayer assays. Additionally, AST's impact on cytokine secretion was measured in LPS-stimulated RAW264.7 macrophages via ELISA. 16S rRNA sequencing and metabolomic analyses were conducted to examine AST's influence on gut microbiota and metabolite profiles. Key differential metabolites identified from these analyses were further validated through in vitro experiments.

[RESULTS] AST significantly reduced the number of intestinal polyps in both animal models, with inhibition rates of 50 %-60 %, by modulating inflammatory cell infiltration and the release of proinflammatory cytokines. In vitro, AST inhibited the proliferation of Caco-2 and HCT116 cells, enhanced TEER, and significantly decreased FITC-dextran permeability in monolayers following TNF-α stimulation. Microbiomic and metabolomic analyses demonstrated that AST restored gut microbiota composition and metabolic balance. Correlation analysis revealed significant relationships between microbiota, metabolites, polyp number, and inflammatory cytokines. Furthermore, typical differential metabolites were shown to inhibit IL-6 and TNF-α secretion in vitro, with valeric acid notably restoring tight junction protein expression, enhancing TEER, and significantly decreasing FITC-dextran permeability in monolayers.

[CONCLUSION] AST inhibited intestinal polyp formation by restoring barrier integrity, and modulating gut microbiota-metabolite networks to reduce local inflammation. This study highlights AST's potential as a preventive agent against intestinal polyps by targeting multiple key pathways in polyp progression.