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..
Buchu. - Synonym. - Bucco. The leaves of Barosma betulina (Thunberg) Battling et Wendland, and Barosma crenulata (Linne) Hooker (nat. ord. Rutaceae).
About 15 mm. long, roundish-obovate, with a rather wedge-shaped base, or varying between oval and obovate, obtuse, crenate or serrate, with a gland at the base of each tooth, dull yellowish-green, thickish, pellucid-punctate; odor and taste strongly aromatic, somewhat mint-like, pungent and bitterish. Resembling Buchu. - Senna and Uva Ursi, which have entire leaves.
Impurity. - Leaves of Emplanum serrulatum, which have no glands.
The chief constituents are - (1) A yellowish-brown volatile oil, from the glands. (2) A stearopten (Diosphenol, C10H16O2) in solution in a liquid hydrocarbon. The stearopten is deposited on exposure to air. (3) A glucoside Barosmin, soluble in alcohol (scarcely so, if cold) and in ether, volatile oils, dilute acids and alkalies. (4) Rutin, a bitter principle. (5) Mucilage.
Dose, 15 to 30 gr.; 1. to 2. gm.
By maceration and percolation with Alcohol, and evaporation. Dose, 15 to 30 m.; 1. to 2. c.c.
A medicinal dose of buchu causes a slight feeling of warmth in the stomach, and a large one gives rise to vomiting. The volatile oil diffuses into the blood and is excreted by the bronchial mucous membrane, which it stimulates, and buchu is therefore occasionally given as an expectorant. Most of the oil is excreted by the kidneys, which are also stimulated, and thus buchu is a mild diuretic. In the process of excretion it gives a peculiar odor to the urine, and acts as an astringent and disinfectant to the urinary tract, especially the bladder. It has consequently been administered for cystitis, irritable bladder, pyelitis, gonorrhoea, etc. Large doses continued for a long time are said to damage the kidney. The infusion B. P., 1 to 20, dose 1 to 2 fl. oz., 30. to 60. c.c. contains very little of the oil. The fluid extract does not mix well with water on account of the oil in it. The action of the buchu is much the same as that of pareira, (q. v.) but it is pleasanter to take, and is a good vehicle for diuretics.