Characterization and immunomodulatory activities of sulfated polysaccharides from Capsosiphon fulvescens

Sulfated polysaccharides isolated from Capsosiphon fulvescens and fractionated using ion-exchange chromatography were investigated to determine their chemical and molecular characteristics and biological activities. The crude and fractionated polysaccharides (F1, F2, and F3) consisted mostly of carbohydrates (28.9-67.0%), uronic acids (1.6-9.2%) and sulfates (5.2-13.4%) with various amounts of proteins (2.1-53.7%). Their monosaccharide levels were significantly different including rhamnose (20.8-65.2%), xylose (13.0-37.1%) and mannose (11.6-65.1%). The polysaccharides contained one or two subfractions with molecular weights (Mw) ranging from 401.7 × 103 to 6232 × 103 g/mol. These polysaccharides (the crude and fraction F2) strongly stimulated macrophage cells, RAW264.7 cell line, producing considerable amounts of NO, PGE2 and cytokines which suggested that they could be strong immunostimulators. The main backbone of the most immunoenhancing polysaccharide (F2) was suggested by GC-MS and NMR to be the following: