Exopolysaccharides (EPS) extracted with hot water from Spirulina platensis were characterized. The mass performance of water-soluble exopolysaccharides of Spirulina platensis suspension is 13.95%. The chemical composition of ESP was mainly consisted of 72.23±1.37% carbohydrates, among them 26.6±1.48% are neutral monosaccharides and 45.47±0.98% are uronic acids. Chromatographic analyzes using four TLC systems after 2M TFA hydrolysis at 80°C for 4 h indicate that ESP are composed mainly of glucoronic acid, arabinose and mannose. In vitro study shows that EPS of S. platensis exhibited anticoagulant activity as compared with heparin, a standard anticoagulant. The anticoagulant activity was detected by prolongation of activated partial thromboplastin time (APTT) and prothrombin time (PT). The EPS extract at 0.1% showed >300 s of APTT activity. In PT assay, almost all tested concentration did not show good activities. According to the results, the EPS extract strongly inhibit the endogenous pathway of coagulation.
