C20H20O10 = 420.16.
Scoparin, C19H16O8(OH) (OCH3), is a phenolic substance (not a glucoside), occurring in broom, Cytisus scoparius, Link. (N.O. Leguminosae), and may be prepared by boiling the tops and twigs of the plant in water, evaporating the decoction to a low bulk, and allowing to stand for twenty-four hours. The gelatinous, crude scoparin thus obtained is washed with a little cold water, dissolved in boiling water containing a few drops of hydrochloric acid, filtered and set aside to solidify; the jelly again formed is purified by washing, pressing, and drying over a water-bath. Scoparin occurs as a tasteless, odourless, neutral, pale yellow, amorphous, brittle mass, or as a yellow, crystalline powder. When slowly heated the substance puffs up, and melts at about 202°; if quickly heated it Melts at about 219°; on further heating it carbonises without subliming, and burns with a bright flame. Chlorinated lime colours its aqueous solution dark green; bromine gives a bluish-green colour. By the action of nitric acid, picric acid is formed. Neutral and basic lead acetates give a yellowish-green precipitate, but silver nitrate and mercuric chloride have no action. On fusion with potassium hydroxide, acetovanillone, phloroglucinol and protocatechuic acid are formed. Hot alcohol converts it into a mixture of a jelly-like, insoluble, and a crystalline soluble modification.
Scarcely soluble in water; soluble in hot water, forming a light, greenish-yellow solution; slightly soluble in alcohol; soluble in hot alcohol; easily soluble in solution of ammonia and in solutions of the caustic alkalies and their carbonates. The solutions in caustic alkalies are greenish-yellow, and deposit a greenish-brown resin on boiling. Hot aqueous solutions reduce alkaline copper and silver solutions. Scoparin is precipitated as a jelly from the cold ammoniacal solution, by excess of hydrochloric acid.
Action and Uses.—Scoparin is said to be the chief cause of the diuretic action of broom tops, and it may be administered in place of the preparations of the crude drug, either in mixture form with sodium bicarbonate, or hypodermically, dissolved by the aid of a very small quantity of solution of ammonia.
Dose.—3 to 5 decigrams (5 to 8 grains); hypodermically, 3 to 5 centigrams (½ to 1 gram).