Anticoagulant screening of marine algae from Mexico, and partial characterization of the active sulfated polysaccharide from Eisenia arborea.

Abstract

The in vitro anticoagulant activity of 41 water extracts of various seaweeds from Baja CaliforniaSur, Mexico was evaluated. In this study, nine extracts exhibited anticoagulant activity in the prothrombin time assay and 29 extracts were positive in the activated partial thromboplastin time assay. The water extract obtained at 25 °C from the brown seaweed Eisenia arborea was the most active in both assays, increasing the normal blood clotting-time over 300 s at 100 mg mL-1. The fractionation of this extract by anion exchangechromatography yielded 3 fractions. Fraction 2 eluted with 1.0 M sodium chloride increased the clotting-time over 300 s in the activated partial-thromboplastin time assay at 5 mg mL-1, being more active than sodium heparin. Chemical and spectroscopic analysis of fraction 2 showed it to be a sulfated heterofucan composed of 56.2 % ± 0.1% of total sugars and 45 % of sulfates.The neutral sugar constituents of the active heterofucan was determined to be 47.6 % fucose, 35.5 % xylose and 16.9 % rhamnose, with substitutions of sulfate groups at C-4 (axial), and minor substitutions at C-2 and-or C-3.