Polysaccharides, brown algae

These materials are another polysaccharide. The name derives from its original source, brown algae. The current commercial sources are brown seaweeds such as Laminaria digitata, L. hyperborea, Ascophyllium nodosum and Fucus serratus. Different properties are obtained in alginates from different seaweeds. The sources are rocky coasts in the United States, the United Kingdom, France and Norway. 

Among the plant polysaccharides there may be mentioned the hemi-celluloses the most common of these contain 4-O-methyl-D-glucuronic acid as branch units linked to a /3-D-xylan backbone.110 The commercially important gum arabic, a soluble polysaccharide produced by Acacia trees and widely used in foods and pharmaceuticals, also contains glucuronic units.111 D-Glucuronic acid has been found in sulfated complex polysaccharides from brown algae.112... 

D-Mannuronic acid (36) constitutes the major component of alginic acid, the main polysaccharide of the brown algae, in which L-guluronic acid (37) is also found. The ratio of D-mannuronic acid and L-guluronic acid can vary with the algal species, the type of tissue, and the age of the plant. In the case of Laminaria hyperborea, L-guluronic acid is the major component.130... 

B. Larsen, A. Haug, and T. J. Painter, Sulphated polysaccharides in brown algae. I. Isolation and preliminary characterization of three sulphated polysaccharides from Ascophyllum nodosum (L.) Le Jol, Acta. Chem. Scand., 20 (1966) 219-230. 

Polysaccharides from plants, too, can form gels in water. Pectin is used to help gel jams and fruit preserves. Some polysaccharides are used to thicken foods. Alginic acid, extracted from brown algae, is a linear polymer containing many carboxylic acid groups. The sodium salt is soluble in water and is used as a thickener in the preparation of ice cream and other foods. If a sodium alginate solution is mixed with calcium ion, the polysaccharide pre-... 

Most of the research on marine compounds with anti-HIV activity has focused on sulphated polysaccharides (PS) and proteins. Sulphated polymannuroguluronate is a marine sulphated PS which has entered phase II clinical trials in China as the first anti-AIDS drug candidate obtained from marine brown algae. Miao et al. [19] investigated the binding site(s) receptors of this compound in lymphocytes mediating its anti-AIDS activities. These results indicate that the interaction of this PS and CD4 may provide a mechanistic explanation of its immunopotentiating and anti-AIDS activities in HIV-infected individuals. 

Alginates are a family of polysaccharides mainly extracted by brown algae. Alginate hydrogels are able to store up to 100 times their weight of water, trapped in a network of hydrophilic fibrils. This property accounts for their natural occiurence as water reservoirs in plants of the tidal area [6]. 

A xylan has been found in Chlorophyta, Rhodophyta, and Phaeophyta (brown algae). The skeletal polysaccharide of die green algae Caulerpa, Halimeda, and Udotea is a (1 3)-j8-D-xylopyranan, coiled helically to form microfibrils. In contrast to the crystalline lattice of cellulose, which could not be penetrated by water, the helical arrangement in the )8-D-(l — 3)-linked xylan allows in the lattice considerable hydration and hydrogen bonding, and these contribute to... 

Bruhn, T. Duerig, J. Kraiselburd, E.N. De Clercq, E. Bruhn, H-D. Beress, L. Antiviral and Anticoagulant Activity of Polysaccharides from marine brown algae. 

Experiments have been performed on enzymes likely to hydrolyze polysaccharides (laminarin and algin) more specific to brown algae. 

CgHgOg) ) A yellow-white organic solid that is found in brown algae. It is a complex polysaccharide and produces, in even very dilute solutions, a viscous liquid. Alginic acid has various uses, especially in the food industry as a stabilizer and texture agent. 

The polysaccharide laminarin is commerdally extraded mainly from kelp and fucoids and is a main form of food storage of brown algae. Sulfated laminarins have antilipidemic activities and capable of reducing serum cholesterol levels and total serum lipids (Kiriyama et al., 1969). The anticoagulant activity of this material is attributed to its antithrombotic... 

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