Carrageenans from cystocarpic and sterile plants of Chondrus pinnulatus (Gigartinaceae, Rhodophyta) collected from the Russian pacific coast

The chemical structure, gel properties and biological activity of the carrageenans isolated from cystocarpic and sterile plants of Chondrus pinnulatus were investigated. The total carrageenan content of the sterile plant was observed to be twice that of the cystocarpic plants. According to data obtained by C-13-NMR and FT IR, the gelling polysaccharides from cystocarpic and sterile plants of C. pinulatus have similar structures and were identified as kappa/iota-carrageenans. The difference between these polysaccharides was in the ratio of the kappa- and iota-segments, with a predominant content of kappa-segments in cystocarpic plants (80%). Moreover, KCl-insoluble fractions possibly contain hetero-disperse mu/nu precursor: amounts of this in the polysaccharide from sterile plants were more than that extracted from the cystocarpic plants. The KCl-soluble fractions (non gelling) were lambda-carrageenans with another carrageenan type that had a low amount of 3,6-anhydrogalactose. Carrageenans from cystocarpic stages showed good gelling properties, whereas those from sterile plants formed a very weak gel. Structural differences and molecular weight of carrageenans obviously determine the biological activity of the polysaccharides. Non gelling-carrageenans from both types of iota t C. pinnulatus plants showed high macrophage-phosphatase activity and kappa/iota-carrageenan from cystocarpic plant possessed a potent anti-coagulant activity, which was extremely strong in a low concentration of 100 mu g ml(-1).