The anticoagulant activity of carrageenan

Abstract

Abstract λ-Carrageenans and κ-carrageenans from samples of Chondrus crispus, carrageenan from Polyides rotundus and degraded carrageenan from Eucheuma spinosum have anticoagulant activity on intravenous injection in the rabbit. Anticoagulant activity appears to be caused by a general reaction with plasma protein. The undegraded carrageenans are acutely toxic on intravenous injection and form insoluble complexes with fibrinogen in neutral solution. Degraded carrageenan is very much less toxic and, like heparin, forms soluble complexes with fibrinogen. The λ-carrageenans from C. crispus have higher sulphate content, consistently prolong the clotting time more, and are more toxic than the corresponding κ-carrageenans. The differences in sulphate content between the various λ-carrageenans, and between the carrageenans from the other seaweeds tested, do not correspond directly with differences in anticoagulant action and toxicity.