Anticoagulant activity of sulfated polysaccharides fractions from an aqueous extract obtained from the red seaweed Halymenia floresia (Clemente) C. Agardh

Heparin (HEP) is known due to their side effects and the red seaweed Halymenia floresia (Hf) sulfated polysaccharides (SP) are heparinoids. In this study we purified the Hf-SP obtained from an aqueous extract and evaluated their anticoagulant activities. Hf-SP 1 (25°C), Hf-SP 2 (80°C) and Hf-SP 3 (80°C) were sequentially isolated. Hf-SP3 had the highest sulfate content (37.45%). Hf-SP 3 was fractionated by ion exchange chromatography on a DEAE-cellulose column using a NaCl gradient. Fractions were lyophilized and submitted to 0.5% agarose gel electrophoresis. The anticoagulant activity was evaluated by the activated partial thromboplastin time using rabbits plasma and expressed in international units per mg of SP using standard HEP (193 IU mg -1 ). The chromatographic procedure separated into four different SP fractions (F I, F II, F III and F IV) eluted at concentrations of 0.50, 0.75, 1.00 and 1.25 M of NaCl, respectively, reveling among them different marked on charge density, when compared by electrophoresis. F III had the highest anticoagulant activity (10.72 IU mg -1 ), suggesting that the sulfate is important in this process. In conclusion, our results suggest that sequential extractions of Hf-SP are an important biotechnological tool for identification of novel anticoagulants and studies of structural characterization are already in progress.