Characterization And Biological Activities Of Polysaccharides From Two Species Of Brown Algae

Studies on polysaccharides from two kinds of brown algae,Sargassum maclurei and Costaria costata were rarely concerned.In this study,the polysaccharides were extracted from S.maclurei and C.costata by hot-water or dilute acid extraction,and purified through anion exchange chromatography with DEAE Sepharose FF-column.The structure and chemical characteristic were elucidated based on FT-IR,NMR and normal chemical analysis.Results showed that the polysaccharide from S.maclurei was a kind of sulfated heteropolysaccharide composed of fucose,glucouronic acid and several other monosaccharides.While the polysaccharide from C.costata was a complex and highly acetylated polysaccharide that sulfated mainly at C2 position of galactose and fucose residues.The antioxidant activity of polysaccharide from S.maclurei was examined in vitro.Results showed that the S.maclurei polysaccharide had great antioxidant activity with strong ability to remove free radicals.Meanwhile,the antioxidant capacity was positively related to the concentration of polysaccharides,and the polysaccharides extracted by hot water had better antioxidant capacity.The anticoagulant activities of polysaccharides from S.maclurei and C.costata were determined in vitro by the APTT,PT and TT assays using the sheep plasma.Results showed that they all had great anticoagulant activity,and polysaccharides from C.costata were better.The polysacchrides prolonged the APTT and TT,suggested they had anticoagulation activities by inhibiting the intrinsic pathways.Meanwhile,the results showed a positive correlation between clotting time and sulfate content.While the low molecular weight components had no distinct prolongation of APTT,PT and TT,indicating that the molecular weight might also play an important role in the anticoagulant activity of polysaccharides from brown algae.The Ba F3 lymphoid cell lines were used to determine the activity of polysaccharides that to activate the fibroblast growth factors/ fibroblast growth factors receptors(FGF/FGFR)signaling.The results showed that the crude polysaccharides from S.maclurei and its degradation had great activity to activate the signal.And the polysaccharides from C.costata especially the fractions without degrading activated all the tested FGF/FGFR pairs greatly,while the effects of different components with different sulfate content to the FGF-1,-2,-7,-8,-9 and-10 were slightly different.It indicated that the FGF/FGFR signal activating activity was correspond with the sulfate group and the molecular weight.