Heterofucans from the brown seaweed Canistrocarpus cervicornis with anticoagulant and antioxidant activities

Abstract

Fucan is a term used to denominate a family of sulfated polysaccharides rich in sulfated l-fucose. We extracted six fucans from Canistrocarpus cervicornis by proteolytic digestion followed by sequential acetone precipitation. These heterofucans are composed mainly of fucose, glucuronic acid, galactose and sulfate. No polysaccharide was capable of prolonging prothrombin time (PT) at the concentration assayed. However, all polysaccharides prolonged activated partial thromboplastin time (aPTT). Four sulfated polysaccharides (CC-0.3/CC-0.5/CC-0.7/CC-1.0) doubled aPTT with only 0.1 mg/mL of plasma, only 1.25-fold less than Clexane, a commercial low molecular weight heparin. Heterofucans exhibited total antioxidant capacity, low hydroxyl radical scavenging activity, good superoxide radical scavenging efficiency (except CC-1.0), and excellent ferrous chelating ability (except CC-0.3). These results clearly indicate the beneficial effect of C. cervicornis polysaccharides as anticoagulants and antioxidants. Further purification steps and additional studies on structural features as well as in vivo experiments are needed to test the viability of their use as therapeutic agents.

Keywords: Dictyota cervicornis; free radicals; fucoidan; sulfated polysaccharides.

Figure 1

Anticoagulant activity by aPTT test. Results were expressed as aPTT ratio, obtained by dividing clotting time achieved with the anticoagulant by that obtained with the control. Data are expressed as means ± standard deviation of four determinations; ^a,b,c,d Different letters indicate a significant difference between each concentration of the same sulfated polysaccharide using one-way Anova followed by the Student-Newman-Keuls test (p < 0.05). Cx: Clexane^®.

Figure 2

Total antioxidant capacity of sulfated polysaccharides extracted from the marine brown seaweed C. cervicornis. The results are expressed as ascorbic acid equivalents. Each value is the mean ± SD of three determinations: ^a,b,c Different letters indicate a significant difference (p < 0.05) between sulfated polysaccharides.

Figure 3

Ferrous chelating activity of sulfated polysaccharides from the brown seaweed C. cervicornis. Each value is the mean ± standard deviation of three determinations: ^a,b,c Different letters indicate a significant difference (p < 0.05) between each concentration of the same sulfated polysaccharide.