PB0320 - "Characterization and Hemostatic Effects of Sulfated Galactan Polysaccharide Fractions from the Green Alga Penicillus capitatus"

Background: Sulfated polysaccharides (SP) abundantly found in marine organisms exhibit significant pharmacological effects across various biological systems. Leveraging their linear and repetitive structure, these compounds serve as pharmacological tools in studies aiming to correlate structure with biological activity.

Aims: In this study, we isolated and characterized two distinct polysaccharide fractions, designated as F23 and F44, from a sulfated galactan extracted from the green alga Penicillus capitatus, each displaying subtle differences in sulfation pattern and glycosidic bond.

Methods: Extraction and characterization of the polysaccharide fractions were performed as illustrated in Fig 1, with structural insights gained through NMR analysis. To assess effects on the coagulation system, we employed aPTT, recalcification time (RT), and anti-Xa and anti-IIa assays. Factor XII activation was evaluated using the chromogenic substrate for kallikrein. In vivo experiments utilized FeCl3 arterial injury and the vena cava stasis thrombosis models. Statistical analysis employed OriginPro 2018 software, with significance determined through one-way analysis of variance and Bonferroni’s post-hoc test.

Results: While F44 exhibited higher anticoagulant activity than F23 in the aPTT assay, both fractions demonstrated procoagulant activity in RT assays, particularly F23. Anti-Xa activity was higher for F23 than for F44. Both fractions activated factor XII. In vivo assays revealed a prothrombotic effect in the arterial model, as evidenced by reduced occlusion time, and in the venous model, with a 34% increase in thrombus weight.

Conclusion(s): Previous literature has suggested that sulfated galactans may exert a dual effect on the coagulation system by activating factor XII and/or platelets. Further investigations are warranted to elucidate the mechanism of action of sulfated galactans from P. capitatus on hemostasis, involving a comprehensive array of in vitro and in vivo assays.
1- Fonseca, RJC.; et at. Slight Differences in Sulfation of Algal Galactans Account for Differences in Their Anticoagulant and Venous Antithrombotic Activities. Thromb. Haemost. 2008.