Polysaccharides from the skin of the ray Raja radula. Partial characterization and anticoagulant activity.

The polysaccharide fraction from the skin of the ray Raja radula was extracted, characterized and assayed for anticoagulant activity. A whole polysaccharidic fraction was extracted from the skin of the ray Raja radula by papain digestion followed by cetylpyridinium chloride and ethanol precipitation and was subjected to gel chromatography and anion exchange chromatography, acetate cellulose electrophoresis and characterized by physicochemical procedures. APTT and anti Xa assays were performed to assess the anticoagulant activity of the polysaccharidic fractions in comparison with unfractionated heparin. Gel and anion-exchange chromatography revealed two negatively charged polysaccharidic populations different in both molecular weight and charge. Infrared spectra suggested the occurrence of uronic acids and acetylated hexosamines. The second polysaccharide was highly sulfated, with a sulfate content of approximately 29%. These data suggested that dermatan sulfate (DS) is the sulfate rich polysaccharide whereas hyaluronic acid (HA) is the polysaccharide devoid of sulfate groups. Molecular mass characterization indicated that their average molecular masses were 22 kDa and 85 kDa, respectively. The sulfated polysaccharide, i.e. presumably DS, accounted alone for the observed concentration-dependent anticoagulant activity which was, as measured by APTT, 2 to 3-fold lower than that of heparin. In addition, it had a significant anti-Xa activity. A major-sulfated polysaccharide, likely a dermatan sulfate, was extracted from the ray Raja radula skin. The results indicated that it exhibited a high anticoagulant activity and suggested that it was mediated by both heparin cofactor II and antithrombin.