This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
In irregular masses, containing fragments of leaves, dark brown, brittle, somewhat porous and glossy when freshly broken. It is nearly inodorous, and has a strongly astringent and sweetish taste.
The chief constituents are - (1) Catechutannic Acid, about 45 per cent., the active principle, isomeric with Catechin, and converted into it by boiling or by the saliva, a red color being formed. (2) Catechin or Catechuic Acid C21H20O9+5H2O, probably inactive. Both constituents give a green precipitate with Ferric Salts. (3) Pyrocatechin or catechol gives a green color with ferric chloride.
Incompatibles. - Alkalies, metallic salts, and gelatin.
Impurity. - Starch.
Dose, 10 to 30 gr.; .60 to 2.00 gm.
Dose, 1/2 to 2 fl. dr. • 2. to 8. c.c.
2. Trochisci Catechu. - Troches of Catechu. Catechu, 6; Sugar, 65; Tragacanth, 2 gm.; Stronger Orange Flower Water, a sufficient quantity to make 100 troches. Each troche contains about 1 gr.; .06 gm.
Dose, 1 to 6 troches.
Catechu is a powerful astringent, acting in virtue of its tannic acid, and having a precisely similar action to it. It is used as a troche for sore throat, and the compound tincture is very efficacious for diarrhoea.