[Study of the mechanism of the anticoagulant action of fucoidans].

The comparative study of the anticoagulant activity of fucoidans, sulphated polysaccharides of brown sea algae was carried out in experiments in vivo. It was shown that compounds of this class possess the anticoagulant activity comparable with that of heparin but with a different mechanism of action. The anticoagulant effect of fucoidans is determined by inhibition of the activity of the blood coagulation "internal" route factors - XI, XII and VIII, the activity of the prothrombin complex factors - II, V and X not changing significantly. It was established that a reduction of the activity of the factors belonging to serine proteases occurs mainly without involvement of antithrombin III.