The dried leaves of Barosma Betulina (Thunberg) Bartling and Wendland, known commercially as short buchu, or of Barosma Serratifolia (Curtis), Willdenow, known commercially as long buchu, with which may be mixed not more than 10 per cent. of the stems of the plants or other foreign matter.
BOTANICAL CHARACTERISTICS.—Shrubby plant. The characteristics common to the buchus are opposite leaves, small, simple, coriaceous, dotted with pellucid glands. Flower pink (betulina), white (crenulata), solitary on axillary or terminal peduncles. Fruit composed of five follicles, adherent at the axis and dehiscing at the summit.
HABITAT.—Southern Africa, Cape of Good Hope.
DESCRIPTION OF DRUG.—About 15 mm. long, varying between oval and obovate, yellowish-green, apex obtuse, margin crenate or serrate with a gland at the base of each tooth, base more or less wedge-shaped; coriaceous, both surfaces beset with numerous slight projections; odor strong and characteristic; taste somewhat mint-like, pungent and bitterish. B. serratifolia (very narrow, linear-lanceolate) con. stitute the "long buchu" of commerce. The long buchu (off. in U.S.P. 1890) contains less of the volatile oil. Transverse sections show a subcuticular layer of thickened cells, rich in mucilage, and containing sphaero-crystals. Both kinds usually require careful garbling, as they are often mixed with branchlets, fragments of capsules, and with leaves of allied species. The long buchu is sometimes mixed with the leaves of Empleurum serrulatum, but these are still narrower, often longer, and terminate in an acute point, without an oil duct.
Powder.—Characteristic elements: See Part iv, Chap. I, B.
CONSTITUENTS.—Volatile oil is contained in large circular cells just beneath the epidermis of the under surface of the leaf; the short buchu yields the greater per cent. (1 to 1.56 per cent.). On exposure to cold it separates out barosma camphor, which existed in the oil dissolved in a hydrocarbon. The upper surface of the leaves swells up in water, due to a layer of mucilage cells just beneath the surface. The bitter principle is rutin; resin is also present.
ACTION AND USES.—A mild diuretic in disorders of the urinogenital organs, its action depending upon the volatile oil. In Cape Colony the leaves are employed as a stimulant and stomachic. Dose: 15 to 45 gr. (1 to 3 Gm.).
Fluidextractum Buchu, Dose: 15 to 60 drops (1 to 4 mils) .