Iodine amyloid

The seeds of Tamarindus indica contain polysaccharides which can be extracted with hot water and purified by precipitation with alcohol. The polysaccharide is composed of D-galactose, D-xylose, and D-glucose (Fig. 10). These xyioglucans have been named amyloids since they give a color reaction with iodine similar to starch. The xyioglucans from Tamarindus are gel-forming polysaccharides which are stable in a wide pH range. This type of polysaccharide is mainly used in food industry, but, in some cases, it has been pharmaceutically employed as a substitute for pectin. 

Amyloid.—When treated with concentrated sulphuric acid cellulose dissolves and undergoes hydrolysis. If the solution is diluted with water a gelatinous product is obtained which gives the blue color with iodine characteristic of starch. This product is known as amyloid. When boiled in the dilute acid the amyloid is hydrolyzed and dextrin and finally glucose are obtained. Concentrated hydrofluoric acid and phosphoric acid also dissolve cellulose. With glacial acetic acid in the presence of acetic anhydride and sulphuric acid cellulose yields acetyl derivatives indicating its alcoholic character. From the products of this reaction the acetate of a di-saccharose is obtained. 

Amyloid Matter.—ihsoZMftfe in water, saline solutions or dilute acids or alkalies, colored red-brown or violet by iodin. 

V. —Amyloid — is a pathological product, occurring in fine grains, resembling starch-granules in appearance, in the membranes of the brain and cord, in waxy and lardaceous liver, and in the walls of the blood-vessels. Its composition is that of the albuminoids, from which it differs in being colored red by iodin violet or blue by iodin and HjSOt. Soluble in HCl with formation of syntonin and in alkalies. It is not attacked by the gastric juice, and is not as prone to putrefaction as the other albuminoids. 

Cellulose dissolves in concentrated sulphuric acid when the solution is diluted with water and boiled, soluble carbohydrates are formed, which vary in complexity from soluble celluloses and dextrins to dextrose, the final product of hydrolysis. When unsized paper is left in contact for a moment with sulphuric acid diluted with about one-fourth its volume of water, the surface of the paper is converted into a colloidal modification of cellulose called amyloid. After washing in water and dilute ammonia the paper is found to have a smooth surface, and to have been markedly toughened by the treatment. The so-called parchment paper is prepared in this way. Amyloid is colored blue by iodine the reaction is used as a test for cellulose. 

Amyloid is a substance of uncertain composition (111) sometimes found in diseased connective tissues. The name is derived from its resemblance to starch in turning blue when exposed to iodine and dilute sulfuric acid. This method of staining is so poor that it is now seldom used. A... 

Studies suggest that curcumin s anti-fibhllogenic activity involves fibril binding and destabilization as well as direct inhibition of amyloid fibril growth. Iodine-123 labeled curcumin was synthesized and evaluated in a preliminary biodistribution study in mice. 

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