Abstract: Sulfated polysaccharides from marine algae attracted more and more attention as their diverse biological activities. Tumor neovascularization has become a new target for anti-cancer drugs, and antiangiogenic activities of sulfated polysaccharides have been increasingly reported in recent years. In order to discover polysaccharide-type angiogenic inhibitors, a homogenous sulfated galactan, GFP15, was obtained from Grateloupia filicina, by water extraction, DEAE-Sepharose Fast Flow and Sepharose CL-6B gel permeation chromatography. The structure of GFP15 was characterized with monosaccharide composition analysis, absolute configuration determination, methylation analysis, IR and NMR. The results consistently indicate that GFP15 was an agaran-carrageenan hybrid polysaccharide, composed of 3-linked β-D-galactose partially sulfated at positions O4 and O6, and 4-linked α-D-galactose 2,3-disulfate and α-L-galactose 2,3-disulfate. Small quantities of xylose, 3,6-anhydro-α-galactose and 6-methyl-galactose were also present. The antiangiogenic activity of GFP15 was evaluated via the chick chorioallantoic membrane(CAM) assay. GFP15(100 μg/egg) could reduced new vessel formation. These results indicate that as a potential angiogenesis inhibitor, GFP15 may be a good candidate for future development as an anti-cancer agent.

Key words: Grateoupia filicina, Sulfated galactan, Antiangiogenic activity