In vitro antiviral activities of sulfated polysaccharides from a marine microalga (Cochlodinium polykrikoides) against human immunodeficiency virus and other enveloped viruses.

A marine microalga, Cochlodinium polykrikoides, produces extracellular sulfated polysaccharides. Isolation and purification of the polysaccharides were accomplished by precipitation with ethanol and Cetavlon, followed by DEAE-cellulose column chromatography (polysaccharides A1 and A2). These polysaccharides, which were homogeneous when analysed by both ultracentrifugal and electrophoretic methods, were composed of mannose, galactose, glucose and uronic acid, together with sulfate groups (S = 7-8% w/w). Both A1 and A2 inhibited the cytopathic effect of influenza virus types A and B in MDCK cells, that of respiratory syncytial virus types A and B in HEp-2 cells, that of human immunodeficiency virus type 1 in MT-4 cells; and, except A1 for herpes simplex virus type 1 and A2 for parainfluenza virus type 2 in HMV-2 cells, the cochlodinium polysaccharides showed no antiviral activity against parainfluenza virus types 2 and 3, measles virus, mumps virus or herpes simplex virus type 1 in HMV-2 cells. No cytotoxicity for host cells was observed with these polysaccharides at a concentration of 100 micrograms ml-1. Inhibitory effects on various viruses were achieved at concentrations that were not markedly inhibitory to the blood coagulation process.