Protective Effect of Liriope platyphylla Root Extract on Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Ulcerative colitis (UC), a major form of inflammatory bowel disease, is characterized by chronic inflammation of the colon resulting from disruption of the intestinal barrier and excessive immune activation. Natural compounds with immunomodulatory properties and fewer adverse effects have therefore attracted attention as potential alternatives to conventional therapies. In this study, therapeutic effects of heat-treated Liriope platyphylla root extract (LP) were evaluated in a dextran sulfate sodium (DSS)-induced mouse model of colitis. Oral administration of LP (300 mg/kg/day) markedly ameliorated DSS-induced clinical symptoms, as evidenced by reduced body weight loss, lower disease activity index scores, and restoration of colon length. Histological examination confirmed that LP attenuated mucosal erosion, crypt damage, and inflammatory cell infiltration. LP administration suppressed the DSS-induced upregulation of pro-inflammatory cytokines (tumor necrosis factor-alpha, interleukin 6, interleukin 1 beta) and inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase 2) in both serum and colon tissues. Mechanistically, LP inhibited nuclear translocation of nuclear factor-kappa B (NF-κB) p65 and reduced the phosphorylation of mitogen-activated protein kinase (MAPK) molecules (extracellular signal-regulated kinase, c-jun n-terminal kinase, and p38), indicating suppression of key inflammatory signaling pathways. Moreover, LP helped restore gut microbial balance by reducing pathogenic Enterobacteriaceae and partially increasing beneficial Bifidobacterium populations. Taken together, these findings suggest that heat-treated LP alleviates colitis through the suppression of inflammatory mediators, inhibition of NF-κB and MAPK pathway activation, and modulation of gut microbiota. Therefore, LP may represent a promising natural therapeutic candidate for the management of colonic inflammation.