Antiviral Polysaccharides

Among the natural compounds, polysaccharides represent a class of natural products with a significant antiviral activity, suggesting that they could be explored as novel antiviral agents (Table 1.3). 

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Among natural antiviral agents, recent investigations have reconsidered the interest of phyto-polysaccharides, which act as potent inhibitors of different viruses (Martinez et al. 2005). This section will illustrate a variety of antiviral polysaccharides from natural sources since 1990, with the aim of making this matter more accessible to drug development, some typical examples of such medicines and their antiviral activities are shown in Table 3.3. 

CS derivatives/salts have found limited use as detergents (25), antistatic coatings for photographic film (26), oil drilling fluids (25), thickeners in food, cosmetics, and pharmaceuticals (27). They have been recommended for use as cation exchangers (28,29). Also, sulfated polysaccharides have recendy shown interesting antiviral activity (30). 

Mourier s report was quickly followed by successful enantiomeric resolutions on stationary phases bearing other types of chiral selectors, including native and deriva-tized cyclodextrins and derivatized polysaccharides. Many chiral compounds of pharmaceutical interest have now been resolved by packed column SFC, including antimalarials, (3-blockers, and antivirals. A summary is provided in Table 12-2. Most of the applications have utilized modified CO, as the eluent. 

The red microalga genus Porphyridium is a source of biochemicals possessing nutritional and therapeutic values. The biochemicals include polysaccharides that have anti-inflammatory and antiviral properties, long-chain polyunsaturated fatty acids, carotenoids such as zeaxanthin, and fluorescent phycobiliproteins. 

Emphasis in the initial phase of our work was placed on sulfated polysaccharides that are antiviral. Not only were the desired rheological properties and long-term stability achieved in DCE formulations, the activity of the dextran sulfate or N9 were not compromised. DCE formulations containing DS display strong anti-HIV activity in vitro in comparison with negative (not shown) and positive controls (Figure 2). This is an important first step in the screening process towards clinical effectiveness. 

The pharmacologically active constituents of these Astragalus belong to two different kinds of chemical compounds, polysaccharides and saponins, and the most interesting pharmacological properties are hepatoprotective, immunostimulant and antiviral. 

Attempts have also been made to compile the results of chiral resolutions by SFC using polysaccharide-based CSPs, as summarized in Table 11. To show the nature of the SFC chromatograms, Figure 28 represents the SFC chiral resolution of ibuprofen on a Chiralpak AD CSP. Stringham et al. [144] resolved the enantiomers of four intermediates encountered in the process of developing synthetic antiviral drugs on a Chiralcel OD CSP. In another report, Blackwell... 

Abstract The inhibitory action of polyanionic substances on virus replication was reported more than 50 years ago. Seaweeds, marine invertebrates, and higher plants represent abundant sources of novel compounds of proved antiviral activity. Natural sulfated polysaccharides (SPs) are potent in vitro inhibitors of a wide variety of enveloped viruses, such as herpes simplex virus (HSV) types 1 and 2, human immunodeficiency virus (HIV), human cytomegalovirus (HCMV), dengue virus (DENV), respiratory syncytial virus (RSV), and influenza A virus. Several polysulfate compounds have the potential to inhibit virus replication by blocking the virion binding to the host cell. In contrast, their in vivo efficacy in animal and human systemic infections has undesirable draw-... 

Keywords Antiviral activity Chemical structure Natural sulfated polysaccharides Polyanions Seaweeds... 

There are many classes of chemical compounds with putative antiviral effects. One such class is known broadly as sulfated polysaccharides (SPs). They... 

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]. 

As regards the antiviral compounds derived from microorganisms, the polysaccharides nostoflan and naviculan proved to be active against influenza A virus [54,97]. Chemically synthesized oversulfated derivatives of extracellular GAG and SP, produced by a marine Pseudomonas, prepared by dicyclohexylcarbodiimide-mediated reaction for both polysaccharides, showed antiviral activities against influenza virus type A but not against type B [52],... 

The anionic groups Most of the seaweed polysaccharides with antiviral activity carry only sulfate as their anionic group. Nevertheless, in the case of fucoidans both sulfate groups and uronic acids are present. Sulfated seaweed polysaccharides with degrees of sulfation lower than 20-22% usually do not show activity, unless other structural factors compensate the sulfate deficiency. 

Pujol et al. in chapter eight, reviews the chemistry, origin and antiviral activities of naturally occurring sulfated polysaccharides for the prevention and control of viral infections such as HIV-1 and -2, human cytomegalovirus (HCMV), dengue virus (DENV), respiratory syncytial virus (RSV), and influenza A virus. 

S. Mazumder, P. K. Ghosal, C. A. Pujol, M. A. Carlucci, E. B. Damonte, and B. Ray, Isolation, chemical investigation and antiviral activity of polysaccharides from Gracilaria corticata (Gracilariaceae, Rhodophyta), Int. J. Biol. Macromol., 31 (2002) 87-95. 

M. Witvrouw and E. De Clercq, Sulfated polysaccharides extracted from sea algae as potential antiviral drugs, Gen. Pharmacol., 29 (1997) 497-511. 

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