Anticoagulant activity of a sulfated polysaccharide from the green alga Arthrospira platensis.

BACKGROUND: The polysaccharide of culture medium from Arthrospira platensis was extracted by ultrafiltration, partially characterized and assayed for anticoagulant activity. METHODS: The crude polysaccharidic fraction was fractionated by anion exchange chromatography on DEAE-cellulose, subjected to acetate cellulose electrophoresis and characterized by physicochemical procedures. The anticoagulant effect of the ultrafiltrated polysaccharide was checked by several coagulation tests. RESULTS: Anion exchange chromatography revealed in the whole ultrafiltrated polysaccharidic fraction the occurrence of a sulfated spirulan-like component designated PUF2. The average molecular weight of PUF2 was determined by size exclusion chromatography combined with multi-angle light scattering (SEC-MALS) and viscosimetry and was 199 kDa and the sulfate content was 20% weight/dry weight. The physicochemical characterization indicated the occurrence of rhamnose (49.7%), galacturonic and glucuronic acid (32% of total sugar). The anticoagulant effect of this sulfated polysaccharide was mainly due to the potentiation of thrombin inhibition by heparin cofactor II and was 4-times higher than that of the porcine dermatan sulfate whereas it had no effect on anti-Xa activity. CONCLUSIONS: An ultrafiltrated sulfated polysaccharide, likely a calcium spirulan was obtained from the culture medium of A. platensis and showed an anticoagulant activity mediated by heparin cofactor II. GENERAL SIGNIFICANCE: Old culture medium of A. platensis may represent an important source for the spirulan-like PUF2 which was endowed with potentially useful anticoagulant properties whereas its obtention by ultrafiltration may represent an extraction procedure of interest.

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

INTRODUCTION: The polysaccharide fraction from the skin of the ray Raja radula was extracted, characterized and assayed for anticoagulant activity. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.