Heparinoid-active sulphated polysaccharides from marine algae as potentialblood anticoagulant agents

Anticoagulant properties of marine algae have been extensively studied for the last 60 years. Sulphated polysaccharides (SPS) of three major divisions of marine algae, viz, Rhodophyta, Phaeophyta and Chlorophyta are reported to have such properties. Some of the active components have been chemically well characterized. Sulphated galactans and fucoidan sulphates from red an d brown algae, respectively, and different sugar sulphates like arabinan, r hamnan sulphates, etc. from green algae are the active molecular species id entified. Activity is related to the molecular size, type of sugar and sulp hate content of the active componnt. Sulphate position, type of linkage and molecular geometry are also known to have a role in activity. The proposed mechanisms of action are predominantly on HC-II mediated antithrombin acti vities, direct antithrombin action (thrombin-fibrinogen complex) and minor AT-III involvements. Little anti-factor Xa and fibrinolytic activities are also proposed. Therapeutic interest of algal SPS as anticoagulant has recen tly been in focus. In future, algal SPS can be developed as anticoagulant/a ntithrombotic agents or could be used as a model for the same.