Partial characterization and anticoagulant activity of sulfated galactan from the green seaweed Halimeda opuntia

Abstract

The number of deaths associated with cardiovascular diseases (CVD) increases every year, leading to an intense search for new compounds that may be employed as anticoagulants. One of the classes of bioprospected molecules comprises sulfated polysaccharides (SP) from seaweed, as heparin displays many adverse effects associated with its use. The present study aimed to characterize and evaluate the anticoagulant potential of SP extracted from the green algae Halimeda opuntia. Four PS-rich fractions, F23, F44, F60 and F75, were obtained by proteolytic digestion in papain followed by ethanol precipitation. The presence of SP was confirmed by agarose gel electrophoresis, revealing different populations in each fraction. The F44 fraction is noteworthy compared to the other fractions, presenting a 5% yield compared to the initial algae weight and anticoagulant activity revealed by the activated partial thromboplastin time (APTT) assay (intrinsic/common coagulation pathway). Surprisingly, F44 purification (SP peak P1F44) resulted in prothrombin time (PT) activity (extrinsic coagulation pathway) at a 160 µg/mL, in addition to enhanced APTT activity. The P1F44 anticoagulant activity mechanism was shown to be dependent on two coagulations factors, IIa and Xa, more potent via IIa. Future assessments will be performed to assess this fraction in the medical clinic.

Key words
Marine algae; Sulfated polysaccharides; Blood clotting; Heparin-like; Factor IIa