Polysaccharides from the green seaweeds Codium fragile and C. vermilara with controversial effects on hemostasis

Codium fragile and Codium vermilara biosynthesize water-soluble sulfated arabinans and galactans (and/or sulfated arabinogalactans), α(1 → 4)-d-glucans and β(1 → 4)-d-mannans. The former polysaccharides are composed by 3-linked β-d-galactopyranose and β-l-arabinopyranose residues, they are highly sulfated and substituted with pyruvic acid ketals. For both seaweeds, they have the same main structural units, but in different percentages. All the room-temperature water extracts from both seaweeds showed a dual haemostatic effect: they prevented coagulation, but they induced platelet aggregation. Anticoagulant activity and platelet aggregation were higher in the samples with polysaccharides richer in sulfate, mainly in those from C. vermilara, which have a higher degree of sulfation and arabinose content.