Sulfated polysaccharide extracted from seaweed Gracilaria caudata attenuates acetic acid-induced ulcerative colitis

Marine macroalgae have high concentrations of sulfated polysaccharides (PLS) studies have demonstrated their antioxidant and anti-inflammatory effects. Certain structural features of PLS such as the formation of sulfate clusters are essential for their biological activities. PLS extracted from Gracilaria caudata have shown therapeutic potential and can be considered an alternative for the treatment of inflammatory bowel disease (IBD) such as ulcerative colitis (UC). The study objective is to evaluate an anti-inflammatory action of Gracilaria caudata PLS on acetic acid-induced intestinal damage in UC model in mice. Mice were treated with PLS from Gracilaria caudata 1.0, 3.0, and 10.0 mg/kg, intraperitoneally (ip) or dexamethasone 2.0 mg/kg, subcutaneously (sc) to determine the best dose of PLS to elicit an anti-inflammatory effect on UC. Colonic-tissue samples were collected for macroscopic analysis, wet weight, microscopic, and biochemical (MPO, GSH, MDA, NO3NO2, cytokine levels and Western blotting for iNOS) features. Treatment with PLS attenuated the colonic inflammatory process during the course of UC by reducing the macroscopic and microscopic scores and reducing the wet weight of the colon. Additionally, there was a reduction in MPO enzyme activity, GSH consumption, and reduction in MDA, NO3/NO2 and pro-inflammatory cytokine (IL-1β and TNF-α) concentrations and reduction in iNOS expression. This study indicates that Gracilaria caudata PLS have anti-inflammatory action on acetic acid-induced UC by reducing inflammatory infiltrate, oxidative stress, pro-inflammatory cytokine action, and iNOS expression. The data suggest that PLS have therapeutic potential against IBD such as UC.