A comparative study of the anticoagulant activities of eleven fucoidans.

Seven fucoidans that differed only with respect to the average molecular weight and four fucoidans that differed with respect to both the molar ratio of fucose to galactose and the average molecular weight were obtained. The anticoagulant activities of these fucoidans were determined in order to understand the effects of the average molecular weight and the content of galactose. Fucoidans Y5-Y11, with the average molecular weight in the range of 50.1-8.4 kDa, showed decreasing activity at three concentrations and dose-dependent activity in the APTT and TT assays. Y1-Y4, which differed with respect to the average molecular weight and the molar ratio of fucose to galactose, exhibited complicated results in the APTT and TT assays. It was shown that not only the average molecular weight but also the molar ratio of fucose to galactose affected the anticoagulant activity of fucoidans.