Fractionation, preliminary structural characterization and bioactivities of polysaccharides from Sargassum pallidum

Sargassum pallidum polysaccharides were fractioned using a DEAE-Sepharose fast-flow column and four polysaccharide fractions (SP-P1, SP-P2, PV-P3 and SP-P4) were obtained. Structural analyses indicated that SP-P2 and SP-P4 had higher molecular weights than SP-P1 and SP-P3. SP-P2, SP-P3 and SP-P4 comprised of fucose, rhamnose, arabinose, galactose, glucose, xylose, and mannose in a similar molar ratio, while SP-P1 did not contain arabinose. SP-P2 and SP-P4 had a similar number of (1 -> 6) or (1 ->) glycosidic linkages (1 -> 2) or (1 -> 4) glycosidic linkages and (1 -> 3) glycosidic linkages, while SP-P1 and SP-P3 contained a small number of (1 -> 3) glycosidic linkages. SP-P2 exhibited better bioactivities than SP-P1, SP-P3 and SP-P4, including antioxidant, anti-hemolysis inhibitory, alpha-amylase and alpha-glucosidase inhibitory and antiproliferative activities. These data suggest that S. pallidum has four polysaccharide fractions with different structural features and bioactivities and SP-P2 has potential to be explored as a functional food or complementary medicine. (C) 2016 Elsevier Ltd. All rights reserved.