Anticoagulant activity of sulfated polysaccharides obtained from the brown seaweed Stephanocystis dioica

Background: Brown algae are recognized as a source of sulfated polysaccharides of great economic value and importance in biomedical studies due to their diverse biological activities such as anticoagulant, antioxidant, antiviral, among others. Goals: In this study, an aqueous extract from the brown seaweed Stephanocystis dioica was evaluated to determine its potential anticoagulant activity. Methods: An aqueous extraction was carried out at room temperature to obtain sulfated polysaccharides, which were semi-purified by fractional precipitation with ethanol to obtain three fractions. These fractions were employed in prothrombin time (PT) and activated partial thromboplastin time (aPTT) assays to evaluate anticoagulant activity at different concentrations (6.25-100 µg mL-1). The partial chemical composition (fucose, uronic acids, and sulfates) and SO4/sugar residue ratio were also determined. Results: In the PT assay, at a concentration of 100 µg mL-1, fraction F3 exhibited the greatest coagulation time (76 s), which was four times that of the control. In the aPTT assay, the three fractions extended the control time (28.8 s) to more than 300 s at a concentration of 100 µg mL-1. Partial chemical analysis showed that fractions F1, F2, and F3 are sulfated heteropolysaccharides rich in fucose, with lower concentrations of uronic acids and other sugars. In the infrared spectrum, the observed vibrations at 820 cm-1 indicate a twist of the sulfate group at the equatorial position of the sugar ring at 2-O and/or 3-O positions. Conclusions: The results showed that sulfated polysaccharide from Stephanocystis dioica has potential anticoagulant activity.