CAT′ECHIN

Syn. Catechu′ic acid , Resinous tan′nin . When cubical gambir or catechu, in powder, is treated with cold water, a portion remains undi olved. This is catechin. By repeated solutions in alcohol it may be obtained under the form of white, silky, acicular crystals. Prop., . Catechin strikes a green colour with the salts of iron, but does not precipitate gelatin. When di olved in caustic pota a, and the solution exposed to the air, it absorbs oxygen, and japonic acid is formed. If, instead of caustic pota a, carbonate of pota a is employed, it is converted into rutic acid.