Beta vulgaris L. extract and betanin alleviate dextran sulfate sodium (DSS)-induced colitis in mice by enhancing the intestinal barrier and regulating the gut microbiota to suppress inflammation

The gut microbiota and intestinal barrier are essential for intestinal homeostasis, and their disruption contributes to ulcerative colitis (UC). This study evaluated the protective effects of red beetroot extract (RE) and its major pigment, betanin (BN), against dextran sulfate sodium (DSS)-induced UC in mice. Male C57BL/6 J mice were assigned to Health, DSS, DSS + low-dose RE (LRE, 300 mg/kg), DSS + high-dose RE (HRE, 900 mg/kg), and DSS + BN (50 mg/kg) groups. LRE showed no meaningful protective effects, whereas HRE significantly alleviated DSS-induced body weight loss, colon shortening, mucus layer disruption, and tight junction damage (occludin and claudin-1). BN also improved these outcomes, exhibiting efficacy comparable to HRE, although HRE showed slightly greater improvements across several colitis-related symptoms. Both HRE and BN inhibited NF-κB activation, reduced pro-inflammatory cytokines, and improved microbial balance by enhancing α-diversity, enriching short-chain fatty acid (SCFA)–producing bacteria, and suppressing pathogens. Functional prediction (PICRUSt2) indicated recovery of inflammation-related pathways. Overall, HRE and BN mitigated colitis by reinforcing the gut barrier, suppressing inflammation, and modulating the gut microbiota. • RE and BN alleviated DSS-induced colitis symptoms and restored the mucus layer. • RE and BN suppressed NF-κB activation and reduced inflammatory cytokine levels. • RE and BN promoting SCFA-producing bacteria while reducing pathogenic bacteria. • RE and BN exhibit therapeutic potential in alleviating gut inflammation.