Sulfation, heteropolysaccharides

Comparison of the activity of sulfated homopolysaccharides such as dextran and cellulose esters with that of neutral homopolysaccharides and sulfated heteropolysaccharides such as heparin and heparan sulfuric acid half esters shows potent virucidal activity against human T-cell lymphotropic virus type III (HTLV-III) for the sulfated homopolysaccharides. In contrast, neutral homopolysaccharides have no effect and sulfated heteropolysaccharides exhibit only a little effect on HTLV-III activities. This suggests that the sulfate moiety and the type of polysaccharide are most important in inhibiting growth of HTLV-III [126]. 

Many studies have been conducted to investigate the in vitro antiviral activity of various SPs. Studies have generally concentrated on synthetic dex-tran sulfates (DSs), pentosan sulfates, clinically used heparins, and seaweed-derived carrageenans. Some reviews reported that sulfated homopolysaccharides are more potent than sulfated heteropolysaccharides [2,3]. In general, polysaccharides exhibiting antiviral potential are highly sulfated [4]. 

The cell walls consist of highly sulfated heteropolysaccharide which consists of a complex mixture of neutral and amino sugars, uronic acids, glycine and an aminuronic acid (gulosaminuronic acid) (Table 4) [80-84]. The typical components of minein or pseudomurein are missing. 

Sulfated heteropolysaccharide Nethanochondroitin Glucosaminoglycan Glycoprotein S-layer ... 

Abdel-Fattah, A.F., Hussein, M.M.-E. and Salem, H.M., 1973. Sargassan A sulfated heteropolysaccharide from Sargassum Uni folium. Phytochemistry, 12 1995—1998. 

This fragmentation of the heparin heteropolysaccharide chain proved to be a jS-elimination reaction in which diazomethane acts as the proton acceptor. It is interesting that aryldiazoalkanes (for example, phenyl or substituted-phenyl diazomethanes) cannot be used for a similar j8-eliminative degradation of quaternary ammonium salts of sulfated heteropolysaccharides. 

Heteropolysaccharides are long-chain polymers that contain more than one type of monosaccharide, many of which are amino sugars. As a result, they are often referred to as gly-cosaminoglycans, which include chondroitm sulfate, hyaluronic acid, and heparin. Hyaluronic acid is abundant in the fluid of joints and in the vitreous humor of the eye. Chondroitin sulfate is an important component of cartilage and heparin has anticoagulant function. The structures of the repeat units of these polymers are shown below. 

Heteropolysaccharides (Hyaluronic Acid, Chondroitin Sulfates, Dermatan Sulfate, and Heparins)... 

The endocyclic, enolacetal-forming, 8-eliminative degradation of dermatan sulfate (33) possesses only one other notable stereochemical feature, namely, the hexopyranuronate residue of this heteropolysaccharide is that of L-idopyranuronic acid, in which the C-5 proton and the C-4 leaving-group are both axially attached (as was proved with synthetic, model compounds, discussed later) in the JC(l) conformation. Therefore, the /8-eliminative degradation of dermatan sulfate can be accepted as being a diaxial procedure, as in 38. 

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