Physicochemical characterization and immunomodulatory activity of sulfated Chinese yam polysaccharide.

A sulfated Chinese yam polysaccharide (S-CYP) was obtained from non-starch Chinese yam polysaccharide (CYP) by chlorosulfonic acid-pyridine (CSA-Pyr) method. The physicochemical characteristics and immunological activity of S-CYP were evaluated in this study. Results showed that sulfated modification changed the physicochemical properties of Chinese yam polysaccharide. Body weights and thymus index of the mice in polysaccharides group were increased compared with the cyclophosphamide (Cy)-induced immunosuppressed mice in model group, and could restore the splenomegaly that caused by Cy. It also showed that S-CYP could enhance the immunomodulatory activity on splenic lymphocytes since it could increase the proliferation of splenic lymphocytes and effectively cooperate with ConA to induce splenic lymphocytes differentiation into T lymphocytes. Meanwhile, the number of CD3CD4 and CD3CD8 T lymphocytes was elevated, the CD4+/CD8+ ratio was restored in polysaccharides group. The levels of splenic lymphocytes cytokines (interleukin (IL)-1β, tumor necrosis (TNF)-α), and the levels of immunoglobulin (IgG and IgM) secretion in serum were also increased by S-CYP significantly. These findings demonstrate that CYP and S-CYP can serve as a promising immunomodulator with potential application in functional food and nutraceutical industry.