Inhibition of complement activation by water-soluble polysaccharides of some far-eastern brown seaweeds

Fucoidans and laminarans from Laminaria cichorioides, Laminaria japonica, F ucus evanescens, laminaran from Laminaria gurjanovae, other beta-D-glucans (translam, pustulan and zymosan) and lambda-carrageenan from Chondrus armat us were used to study the effect of water-soluble polysaccharides from seaw eeds on the alternative pathway of complement (APC). beta-D-Glucans and fuc oidans under study differed appreciably from each other by structural chara cteristics, and also by degree of purification. beta-D-glucans, on ability to bind complement, ranked in a line according to a degree of their purific ation. Highly purified P-D-glucans under study did not reveal an ability to bind complement. The fucoidans were divided conventionally into three grou ps according to their action on APC. Highly sulfated alpha-L-fucan from L. cichorioides with the greatest activity toward APC and caused 50% inhibitio n of reaction of activation (RA) of APC in a concentration of 0.5-0.7 mg/ml . Opposite 50% of inhibition of lysis of erythrocytes by sulfated heterogen eous fucoidan from L.japonica was achieved with 20 mg/ml. All other fucoida ns and lambda-carrageenan have activity at 6-10 mg:ml concentration. Decrea sing the sulfate content from 36% up to 9% in sample fucoidans under study was not reflected practically in the 50% inhibition concentration. Apparent ly, the degree of sulfating of fucoidans did not influence their action on APC. But the positive influence of fucose in structure of polysaccharide wa s obvious. (C) 2000 Elsevier Science Inc. All rights reserved.