Study on the effect of Portulaca oleracea L. extract on chronic ulcerative colitis in rats induced by allogeneic antigen and acetic acid

ABSTRACT Purpose: To investigate the effect and mechanism of Portulaca oleracea L. (POL) extract on acetic acid and alloantigen-induced chronic ulcerative colitis in rats. Methods: Ulcerative colitis was induced in rats by sensitization with rabbit colon antigen and acetic acid. Rats received oral sulfasalazine, intestine-quieting tablet, or POL (high, medium, or low dose) for 14 days. Disease activity index (DAI), colonic mucosal damage index (CMDI), and histological score (HS) were assessed. Serum levels of interleukin (IL)-4, IL-8, IL-17, C-reactive protein (CRP), immunoglobulin G (IgG), and interferon-γ (IFN-γ); colonic levels of myeloperoxidase (MPO), epidermal growth factor (EGF), and tumor necrosis factor (TNF)-α; serum hemolysin (by immunoturbidimetry); splenic T lymphocyte subsets (by flow cytometry); and serum IgG, IgM, IgA, C3, and C4 were measured. Results: Compared with the model group, POL significantly reduced DAI, CMDI, and HS scores in a dose-dependent manner—most markedly in the high-dose group (p < 0.01). POL also significantly decreased serum IL-8, IL-17, CRP, IFN-γ, and IgG, and colonic TNF-α and MPO (p < 0.05 or p < 0.01), while increasing serum IL-4 and colonic EGF (p < 0.01). All POL dosage groups significantly increased hemolysin, IgM, and CD4+CD25+/CD4+ levels in rats (p < 0.05 or p < 0.01), while decreasing serum IgG, IgA, complement C3/C4, CD4+/CD8+, and IL-17+ CD4+ (p < 0.05 or p < 0.01). Conclusion: The POL extract exerts therapeutic effects in chronic ulcerative colitis rats, likely by downregulating pro-inflammatory mediators—including IL-8, IL-17, CRP, IFN-γ, TNF-α, and MPO—, as well as serum IgG, IgA, C3/C4, CD4+/CD8+, and IL-17+ CD4+; and by upregulating anti-inflammatory/repair factors—including IL-4, EGF, lysozyme, IgM, and CD4+CD25+/CD4+. These findings support the clinical potential of POL for ulcerative colitis treatment.