earticle

영어

Polysaccharides from brown seaweeds are interesting due to their various biological activities. A water-soluble polysaccharide was isolated and purified from the sporophyll of Korean Undaria pinnatifida by dilute acid extraction, CaCl2 precipitation to remove alginates, and purified DEAE-cellulose chromatography. Structure of this polysaccharide was characterized by various methods such as elemental analysis, HPAEC-PAD, HPLC analysis, FT-IR, FT-Raman, and 1H and 13C NMR. The average molecular mass of this polysaccharide was estimated about 2.1×103 kDa by HPLC. The polymer showed lower electrophoretic mobility (RSH 0.127) than carrageenans (0.096-0.100) and chondroitin sulphate A (0.103), but higher than alginate (0.170). It is consisted of neutral sugar (52.34 % in mass) and sulfate esters (7.4 % in mass), no uronic acid was observed. From the HPAEC-PAD analysis, the monosaccaride composition was shown to be fucose, galactose, xylose, and mannose, with a molar ratio of 1, 0.8, 0.08, and 0.005, respectively. The major monosaccharide was fucose (50.9 mol%), suggesting that it is a fucoidan, a general name of seaweeds polysaccharides containing fucose residues. Other sugars, galactose (44.6 mol%), xylose (4.2 mol%), and mannose (0.3 mol%), were present as minor component. Very intense and broad FT-IR band at 1258-1259 cm-1 were attributed to S=O stretching of sulfate esters. The IR band centered at 840-842 cm-1 was attributed to COS bending of sulfate substituents. Elemental analysis (EA) of this polysaccharide resulted in C (23.03%), H (3.07%) and S (9.18 %). Taken together, these results clearly demonstrated the presence of sulfate groups in this polysaccharide. The degree of sulfation was determined to me 0.93 by DS (moles of SO3- per mole of sugar units) value, which shows about one sulfate group per sugar unit. Consequently the purified polysaccharide was defined as O-acetylated sulphated galactofucan.