The composition and structural characteristics of polysaccharides of the brown alga Eisenia bicyclis

Abstract

The present study examines the polysaccharide composition of the brown alga Eisenia bicyclis. The major polysaccharide of E. bicyclis is shown to be sodium alginate (15.8% of the dry defatted alga weight). The yields of laminaran and fucoidan were 1.4% and 1.3% of the dry defatted alga weight, respectively. The alga contains laminaran (1,3;1,6-beta-D-glucan) that has a unique structure, a high content of 1,6-linked D-glucose residues (the ratio of 1,3: 1,6 linkage is 1.5: 1), and an unusually high molecular weight (19-27 kDa). The fucoidan fractions isolated from E. bicyclis are sulfated and acetylated heteropolysaccharides that differ in their sulfate content and monosaccharide composition.