Thromb Haemost 2001; 86(06): 1540-1546
DOI: 10.1055/s-0037-1616760
Review Article
Schattauer GmbH

Dual Effects of Sulfated D-galactans from the Red Algae Botryocladia occidentalis Preventing Thrombosis and Inducing Platelet Aggregation

Wladimir R. L. Farias
1   Laboratório de Tecido Conjuntivo, Hospital Universitário Clementino Fraga Filho and Departamento de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
2   Departamento de Engenharia de Pesca, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
,
Rômulo A. Nazareth
1   Laboratório de Tecido Conjuntivo, Hospital Universitário Clementino Fraga Filho and Departamento de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
Paulo A. S. Mourão
1   Laboratório de Tecido Conjuntivo, Hospital Universitário Clementino Fraga Filho and Departamento de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
› Author Affiliations
Further Information

Publication History

Received 15 February 2001

Accepted after revision 26 June 2001

Publication Date:
12 December 2017 (online)

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Summary

Sulfated D-galactans occur on the red algae Botryocladia occidentalis as three fractions that differ in their sulfate content. Fractions F2 and F3 are potent anticoagulants. Like heparin, they enhance thrombin and factor Xa inhibition by antithrombin and/or heparin cofactor II. The inhibition potency increases simultaneously with the sulfate content of the fractions. The antithrombotic activity of these sulfated D-galactans was investigated on an experimental thrombosis model in which thrombus formation was induced by a combination of stasis and hypercoagulability. In contrast with heparin, the sulfated D-galactans showed a dual dose-response curve preventing thrombosis at doses up to0.5 mg/ kg body weight but losing the effect at higher doses. This unexpected behavior is probably due to a combined action of the sulfated D-galactan as anticoagulant and also as a strong inducer of platelet aggregation. In platelet-depleted animals the antithrombotic activity at higher dose of sulfated D-galactan is restored and almost total inhibition of thrombus formation is achieved. The sulfated D-galactan has no hemorrhagic effect even at high doses, possibly as a consequence of its effect on platelet aggregation. At comparable dose heparin has an intense bleeding effect. These results indicate that new polysaccharides, with well-defined structures, can help to distinguish events, such as antithrombotic and anticoagulant activities, bleeding and platelet-aggregating effects, which are obscure when induced simultaneously by a single compound.