Structures of acidic polysaccharides from Basella rubra L. and their antiviral effects

In this study four acidic polysaccharides (BRP-1, BRP-2, BPR-3 and BRP-4) were isolated from the aerial part of Basella rubra L. Sugar composition and methylation analyses indicated that both BRP-2 and BRP-4 were native pectins containing dominant homogalacturonan regions and minor ramified rhamnogalacturonan type I regions branched with arabinogalactan type II neutral side chains. They exhibited antiviral activity against herpes simplex virus type 2 by interfering with absorption and penetration of virus to host cells. The most abundant component, BRP-4, showed a high therapeutic efficacy in the mouse model infected intravaginally with herpes simplex virus type 2. Moreover, orally administered BRP-4 resulted in moderate therapeutic efficacy in the mice infected intranasally with influenza A virus, and was shown to stimulate the production of neutralizing antibody and the secretion of mucosal IgA in influenza virus-infected mice.