Anti-Cytomegalovirus Activity of Sulfated Glucans Generated from a Commercial Preparation of Rice Bran

Abstract

Many viruses display affinity for polysaccharides presented at the surface of target cells with high biological relevance for virus attachment and entry. This raises the possibility of the application of polysaccharides, particularly their sulfated modifications, in studies of receptor binding and also in antiviral therapy. In this study, we analysed various sulfated glucans, generated from a commercial preparation of rice bran using chemical, chromatographic, spectroscopic and virological methods. A number of sulfated polysaccharides with different charge densities were generated from a commercial rice bran preparation by aqueous extraction followed by chemical sulfation. The backbone of the type of glucans identified was made up mainly of α-(1→4)-linked glucopyranosyl residues. Sulfate groups were found to be located at C6 and partly at C2 or C3 of glucopyranosyl residues. Sulfation appeared to be very important for anti-cytomegaloviral activity, as desulfation experiments demonstrated an impairment of activity. Using an established cytomegalovirus replication assay with primary human fibroblasts, data demonstrated that the anti-cytomegaloviral effect was determined primarily at the stage of viral entry. Sulfated glucans derived from rice bran possess very promising characteristics for their potential use as entry-inhibiting anti-cytomegaloviral agents.