Michio Fujihara

Isolation, purification, and characterization of fucose-containing sulfated polysaccharides from the brown seaweed ecklonia kurome and their blood-anticoagulant activities

A sulfated polysaccharide fraction, obtained from the hot-water extract of the brown seaweed, Ecklonia kurome by removing laminaran and the major part of alginic acid, gave sulfated polysaccharides (B-I, B-II, C-I, and C-II) by both anion-exchange chromatography on a column of Ecteola-cellulose and by fractional precipitation with ethanol containing 0.3% calcium acetate, and then by gel-filtration chromatography on a Sepharose 4B column. B-I and B-II are composed of fucose, galactose, mannose, xylose, glucuronic acid, and ester sulfate in the approximate molar ratios of 1.00:0.36:0.48:1.08:1.85:2.35 and 1.00:0.81:0.18:0.45:0.61:2.00, respectively. C-I and C-II are composed of fucose, galactose, glucuronic acid, and ester sulfate in approximate molar ratios of 1.00:0.03:0.03:1.61 and 1.00:0.19:0.07:1.48, respectively. Blood-anticoagulant activities with respect to activated partial thromboplastin time (APTT) were approximately 24, 19, 81, and 85% of that of heparin for B-I, B-II, C-I, and C-II, respectively. All the polysaccharides showed slight antithrombin activity. No antifactor Xa activity was observed for any of the polysaccharides.

Isolation and preliminary characterization of fucose-containing sulfated polysaccharides with blood-anticoagulant activity from the brown seaweed Hizikia fusiforme

We reported that a crude, sulfated polysaccharide (SPS) fraction from Hizikia fusiforme showed considerable anticoagulant activity. In order to identify the biologically active substances, we attempted to isolate each of the polysaccharide components from the SPS fraction. As a result, two purified, fucan-like sulfated polysaccharides having anticoagulant activity were obtained. We describe herein the isolation of the purified sulfated polysaccharides, their physical and chemical properties, and their blood-anticoagulant activities

Inhibition of the Generation of Thrombin and Factor Xa by a Fucoidan from the Brown Seaweed Ecklonia kurome

The effects of a fucoidan (C-II), which was purified from the brown seaweed Ecklonia kurome, on the generation of thrombin and factor Xa have been investigated by measuring the amidolytic activities by using the respective specific chromogenic substrates in both plasma and purified systems. C-II inhibited significantly the generation of thrombin in both the intrinsic and the extrinsic pathways, although the intrinsic inhibitory effect by C-II was more remarkable than the extrinsic one. On the other hand, C-II was a good inhibitor of the factor Xa generation in the intrinsic pathway, while it was a poor one in the extrinsic pathway. In the purified systems C-II also inhibited the formation of prothrombin-activating complex (i.e., prothrombinase), but not its activity. The concentration of C-II required for 50% inhibition of thrombin generation was about one-tenth to one-seventh of that of the activity of the generated thrombin in plasma. These results indicate that C-II has an inhibitory effect on the generation of thrombin by blocking the formation of prothrombinase and by preventing the generation of intrinsic factor Xa in addition to its antithrombin activity, and also that the generation-inhibitory effect is more remarkable than C-IIs enhancement effect on the antithrombin activity by heparin cofactor II in plasma.

Purification and chemical and physical characterisation of an antitumour polysaccharide from the brown seaweed Sargassum fulvellum

Abstract A polysaccharide isolated from a hot-water extract of Sargassum fulvellum and purified by gel-filtration chromatography on Sepharose 4B inhibited the growth of subcutaneous Sarcoma-180 in mice. The purified, active substance appeared to be sodium alginate having a mol. wt. of 33,400 and a molar ratio of mannuronic acid to guluronic acid of 2.78.

Biotransformation of digitoxigenin by cultured Strophanthus hybrid cells

Hybrid cells between Strophanthus gratus and S. amboensis were obtained by electrofusion and confirmed to be hybrids through isozyme and RFLP analyses. Because a new and hybrid compound, 17 beta H-periplogenin beta-D-glucoside, was isolated as a biotransformation product of digitoxigenin by the hybrid cells, isomerization of 17 beta-lactone ring on S. gratus and glucosylation on S. amboensis were demonstrated simultaneously as the biotransformation abilities in the hybrid cells. Moreover, the productivity of the hybrid compound was increased by raising the sucrose concentration.