Xanthoxylin alleviates dextran sulfate sodium (DSS)-induced colitis by targeting macrophage infiltration via the tumor necrosis factor (TNF) /nuclear factor-kappa B (NF-κB) signaling pathway.

BACKGROUND

Ulcerative colitis (UC) is a relapsing-remitting inflammatory bowel disease (IBD) hallmarked by mucosal ulceration and bloody diarrhea. Its rising prevalence worldwide has led to a significant healthcare burden. Edible and medicinal herbs (EMHs) represent promising alternative therapies. Xanthoxylin (XT; 2‑hydroxy‑4,6-dimethoxyacetophenone), both an acetophenone and a phenol compound that is isolated from several spp of Zanthoxylum genus, has shown anti-inflammatory effects in other diseases, but its potential in UC remains unexplored.

PURPOSE: We aimed to investigate the therapeutic effects and mechanisms of XT in dextran sulfate sodium (DSS)-induced colitis.

METHODS

To establish DSS-induced model, mice were given 2.5% DSS for 5 days, followed by distilled water for 3 days. XT is injected intraperitoneally. We measured the colon length, disease activity index (DAI), and histopathological score to evaluate XT's impact on inflammation. Multiplex immunohistochemistry (mIHC), flow cytometry, bulk RNA-seq, enzyme-linked immunosorbent assay (ELISA), Western blot, and molecular docking were employed to delve into the mechanisms underlying XT. Indirect co-culture models involving RAW 264.7 with Caco-2 cells and THP-1 with NCM460 cells were applied to further illustrate the multi-target effect of XT in vitro.

RESULTS

Our results confirmed that XT (5 and 10 mg kg⁻¹) proficiently restored the integrity of the intestinal mucosal barrier, reduced local and systemic pro-inflammatory cytokines in DSS-induced colitis. Mechanistically, XT suppressed colonic lamina propria (CLP) macrophage infiltration by mediating the tumor necrosis factor (TNF) /nuclear factor-kappa B (NF-κB) pathway, specifically affecting the F4/80loCD11b+ macrophage subset. In vitro, XT (20-40 µM) exerted protective effects through attenuation of TNF/NF-κB signaling in macrophages and directly stabilizing tight junctions.

CONCLUSION

Xanthoxylin (XT; 2‑hydroxy‑4,6-dimethoxyacetophenone), a phenolic acetophenone from Zanthoxylum spp., exhibits anti-inflammatory efficacy through regulating both F4/80loCD11b+ macrophage infiltration and the TNF/NF-κB pathway, positioning it as a promising agent for UC.