Effect of ascophyllan from brown algae Padina tetrastromatica on inflammation and oxidative stress in carrageenan-induced rats

Sulfated polysaccharide ascophyllan was isolated from the brown algae Padina tetrastromatica and purified by ion-exchange chromatography. Anti-inflammatory effect of ascophyllan fraction against carrageenan-induced paw edema in rats was studied. Paw edema in rats was induced by injecting 0.1 ml, 1 % carrageenan suspension in 0.9 % NaCl solution into the sub-plantar tissue of the right hind paw. Carrageenan caused a significant increase in the activity of inflammatory marker enzymes like lipoxygenases and cyclooxygenase in peripheral blood mononuclear cells and paw tissue and also increased the concentration of prostaglandin E2 (PGE2) and myeloperoxidase (MPO) in paw tissue. When compared to the reference drug diclofenac, ascophyllan fraction-3 (AF3) treatment significantly reduced the activities of anti-inflammatory enzymes, concentration of PGE2 and MPO. AF3 treatment decreased the mRNA level expression of TNF-α and IL-6. Concentration of thiobarbituric acid reactive substances was decreased. Activities of antioxidant enzymes and reduced glutathione level were increased on treatment with AF3. Histopathology of paw tissue showed decreased edema formation and cellular infiltration on supplementation with AF3. Thus the results demonstrated the potential beneficiary effect of ascophyllan fraction on carrageenan-treated rats.