"Buchu Leaves are the dried leaves of Barosma betulina, Bart, and Wendl." Br.

The leaves of the official and other Barosmas and of some Agathosmas, are collected by the Hottentots, who value them on account of their odor ,and under the name of bookoo or buchu, rub them, in the state of powder, upon their greased bodies.

The medicinal species of Barosma are all erect, slender shrubs with opposite leaves, dotted with conspicuous pellucid oil glands, smooth, angular, purplish branches, often of a purplish color, white flowers, and a fruit of five erect follicles. They are chiefly distinguished by their leaves.

Barosma betulina is a small shrubby plant indigenous to Cape Colony. The leaves are collected while the plant is in flower and fruit, then dried. B. serratifolia is a well-developed shrub growing in the mountains of the southwest of Cape Colony. The leaves of both of these plants are collected in the Cape Colony district of South Africa when the plants are in the flowering or fruiting condition. About 90 per cent, of the supply used in the United States comes from Cape Town, South Africa. The other 10 per cent, comes through London. According to Schimmel and Co., the Buchu plant thrives best in a very sandy soil, but it is rather difficult to cultivate as the cuttings do not root readily. The Buchu of commerce always contains more or less foreign material, such as stems, twigs and old worthless leaves, and the U. S. Pharmacopoeia has wisely limited the amount of such admixture to 10 per cent.

Barosma crenulata (L.) Hook, has leaves opposite, ovate or obvate, acute, serrated and glandular at the edge, coriaceous, and full of small pellucid dots on the under surface. The flowers are white or of a reddish tint, and stand solitarily at the end of short, lateral leafy shoots. The non-official species, which have been seen in European markets occasionally, are said to be used in South Africa as substitutes for the official buchu; they are: Barosma Eckloniana Bartl., a plant which has been considered to be only a variety of B. crenulata, has leaves which are rounded at the base, shorter and proportionately wider than those of B. crenulata and also grow upon pubescent shoots.

The leaves of Barosma venusta Eeklon and Zeyher, which are said to have appeared in the London markets, are readily distinguished by their being very much smaller than those of B. betulina, which they otherwise resemble. Barosma pulchellum (L.) Bartl. and Wendl.� The leaves closely resemble those of the B. betulina, being ovate instead of obovate, that is, they are wider at the base. Their odor is quite different, strongly recalling that of citronella, and Schimmel and Company have demonstrated the presence in them of citronellal.

Under the name of Karoo buchu, in 1904 the leaves of the Diosma succulenta L., var. Bergiana H. and S., appeared in London; they are small and heath-like, thick, obtuse, and slightly recurved, and yielded to C. E. Sage (C, D., Ixv, 506, 787) a small semi-solid volatile oil having the odor of peppermint. Another buchu, which has appeared on the market, has leaves resembling very closely those of Barosma scoparia E. and Z. (Pref. & Ess. Oil Bee., 1914, p. 375.)

Buchu is subject to many adulterations both by the leaves of other species of the genus as well as more distantly related leaves. The most important of these adulterations are as follows: Psoralea obliqua E. Mey, or P. bracteata (P. J., 1910, pp. 69 and 464), and Empleurum serrulatum Ait. The leaves of the latter have a more acrid taste, are lanceolate or narrowly linear, about 4 cm. in length, yellowish-green and very acute at the summit. They furthermore acrid taste, are lanceolate or narrowly of the teeth. (For description of many other adulterants, see Holmes, P. J., 1910, Ixxxv, p. 464.)

Description and Physical Properties.
Unground Short Buchu. � Rhomboidally oval or obovate, from 9 to 30 mm. in length and from 4 to 20 mm. in breadth; apex obtuse or rounded and sometimes recurved, base wedge-shaped or obtuse, margin finely dentate, glandular punctate, with an oil gland at the base of each tooth, papillose, longitudinally striate beneath, coriaceous and with a petiole about 1 mm. in length; color bright green to yellowish-green, occasionally olive-gray; odor aromatic, and mint-like; taste camphoraceous. Unground Long Buchu. � Linear-lanceolate from 12 mm. to 4 cm. in length and from 4 to 10 mm. in breadth; apex acute, somewhat rounded; margin sharply serrate. Otherwise resembles Short Buchu.

Structure. � Cuticle thick, somewhat uneven and striated; hairs few, simple, 1-celled, non-lignifled, up to 0.145 mm. in length (Short Buchu), or 0.180 mm. in length (Long Buchu). Stomata absent on the upper surface, numerous on the lower surface, broadly oval, up to 0.040 mm. in length and surrounded by from 4 to 6 neighboring cells; epidermal cells with inner walls mucilaginous and containing colorless sphero-crystal aggregates of hesperidin which strongly polarize light, the latter form giving a brilliant display of colors; a single row of large hypodermal cells beneath the upper epidermis containing mucilage and frequently brownish, feather-like crystal aggregates; palisade cells in a single row below the mucilage cells, and bordering a loose mesophyll, the cells containing numerous plastids and a few rosette aggregates of calcium oxalate; oil cavities occurring mostly near the margin of the leaf, circular in outline and containing globules of oil. Fibro-vascular bundles of midrib and larger veins collateral, in crescent-shaped groups, composed chiefly of tracheas, sieve tubes and non-lignified fibers and separated by collenchyma from the lower epidermis.

Powdered Buchu. � Light green; elements of identification are epidermal cells containing 16 sphere-crystals or crystal aggregates of hesperidin, rosette aggregates of calcium oxalate from 0.015 to 0.030 mm. in diameter, a few simple hairs, lower tissue with numerous stomata, oil secretion cavities and oil globules, and fragments of the fibro-vascular bundles." U. S.

"From twelve to twenty millimetres long, rhomboid-obovate, dull yellowish-green, rigid, cartilaginous when slightly moist. Surface glabrous, bearing small scattered prominences; margin usually sharply denticulate, apex blunt and recurved. Oil glands visible in the leaf, especially in epidermis cells containing yellow especially near the margin. Transverse section exhibits in epidermis cells containing yellow sphero-crystals; inner walls of these cells thick and rich in mucilage. Odor and taste .strong and characteristic." Br.

The leaves of B. betulina constitute the short buchu or round buchu, while those of B. serratifolia are the long buchu of commerce. The leaves of B. crenulata are at present comparatively infrequent in commerce, the parcels usually consisting of those of one of the other species almost unmixed. The species can be recognized by the characters already given.

Buchu leaves yield a volatile oil with a peppermint-like odor. The amount of oil present in the short buchu ranges from 1.5 to 2 per cent., but in the long buchu is much less, usually not over 1 per cent. (Schim. Sep., Oct., 1893). This oil on chilling deposits a stearopten which is known as Barosma camphor or dio-sphenol (it is, however, said not to occur in the oil from B. serratifolia). This substance, which composes about 30 per cent, of the oil, forms crystals which have a melting point of 82� C. and boil at 232� C. with partial decomposition. The residue of the oil after extraction of the diosphenol contains a hydrocarbon, C₁₀H₁₈, and a ketone, C₁₀H₁₈O, which is probably laevogyrate menthone. Spica (P. J., 1885) found in the leaves of the B. crenulata, from which the oil had been extracted, a solid principle diosmin which is considered now to be the same as hesperidin found in orange peel. His results were confirmed by Shimoyama (A. J. P., 1888) who also has prepared several derivatives of diosphenol. The yield of ash varies, according to the researches of H. W. Jones (P. J., ix, 673), from 4.69 to 4.40 in B. betulina, 4.32 to 5.39 in B. crenulata, 5.03 to 5.22 in B. serratifolia; the ash itself was remarkable as containing a great deal of manganese.

Uses � The activity of buchu depends upon the volatile oil, which is eliminated by the kidneys. Under its action there is no marked increase in the amount of the urine, but the oil affects very decidedly the mucous membrane of the genito-urinary tract, perhaps by virtue of some antiseptic power. The remedy is useful in diseases of the urinary organs, such as gravel, chronic cystitis, urethritis and diseases of the prostate. It should not be given when the inflammation is severely acute. An infusion (one ounce in a pint of boiling water) may be given in the dose of one to two fluidounces (30-60 cc.), but the best preparation is the fluidextract.

Off. Prep. � Fluidextractum Buchu, U. S. Infusum Buchu, Br.; Tinctura Buchu, Br.; Elixir Buchu (from Fluidextract), N. F.; Elixir Buchu Compositum (from Compound Fluidextract), N. F.; Elixir Buchu et Potassii Acetatis (from Elixir of Buchu), N. F.; Fluidextractum Buchu Compositum, N. F.

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