Structural Analysis of an Antiviral Polysaccharide Produced by a Dinoflagellate Cochlodinium polykrikoides

摘要

A dinoflagellate Cochlodinium polykrikoides Produced an extracellular acidic polysaccharide in ESM medium at 21.5°C and 3, 500 lux for 50 days. The product was isolated and purified with EtOH and Cetavlon Precipitations, and fractionated by a DEAE-cellulose column chromatography using stepwise elution with phosphotate buffer containing 0.8,1.2, and 2.0M NaCl (pH 7.0), respectively. The polysaccharide eluted with 0.8M NaCl buffer (A-1) was composed of D-glucose, Dgalactose, mannose, fucose, Dgalacturonic acid, and sulfate (14.8%). Polysaccharides eluted by 1.2 M (A-2) and 2.0M (A-3) NaCl buffers had the same chemical components as A-1 except sulfate contents. The disaccharide was obtained by partial hydrolysis and enzyme hydrolysis (Cellulase from Aspergillus niger ), followed by purification by Bio-Gel P2 column chromatography. The disaccharide which has a structure of β-D-Galp(1-4)-D-Glcp was identified by NMR analyses. A-1, A-2, and A-3 had antiviral activities a-gainst respiratory syncytial virus (G-HeLa cells), human immunodeficiency virus type 1 (MT-4 cells), and influenza virus type A (MDCK cells) and no cytotoxicity to cultured host cells. However, desulfated derivative of A-1 (sulfate 0.8% ) lost these antiviral activities and appeared cytotoxicities to G-HeLa and MT-4 cells.