Buchu. U. S. (Br.) Buchu.
"The dried leaves of Barosma betulina (Thunberg) Bartling and Wendland, known in commerce as Short Buchu; or of Barosma serratifolia (Curtis) Willdenow, known in commerce as Long Buchu (Fam. Rutaceae), without the presence or admixture of more than 10 per cent. of stems or other foreign matter." U. S. "Buchu Leaves are the dried leaves of Barosma betulina, Bart. and Wendl." Br.
Buchu Folia, Br.; Folia Bucco, Folia Diosmae s. Barosmae; Feuilles de Bucco (Booko, Buchu), Fr.; Buckublätter, Bucco-blätter, G.
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.
Buchu leaves are not recognized except in the U. S. and British Pharmacopoeias. The definitions for this drug do not show any great stability, at one time the " short" buchu being official and then again both the "short" and the "long" buchus are included in one definition. This latter is a mistake as the oils in the several buchus are quite distinct. The drag was exploited in the 70's in the United States by Helmbold who was one of the most eccentric and fantastic exploiters of proprietary medicines. (See A. J. P., 1916, p. 23.) 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 carpels. 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 and shipped to London. B. serratifolia is a well developed shrub growing in the mountains of the Southwest of Cape Colony. The leaves usually command a higher price and are only employed when the supplies of short buchu are reduced. The exports of buchu from South America in 1908 were 243,742 pounds, in 1912, 223,000 pounds, in 1913, 163,000 pounds, and in 1914 about 75,000 pounds. 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.
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 crenulata (L.) Hook.—The leaves are opposite, ovate or obovate, 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. C. J. .S. Thompson has found that the leaves of B. serratifolia yield only 3.45 per cent. of resin and 1 per cent. of volatile oil, while those of B. crenulata yield 3.75 per cent. of resin and 1.6 per cent. of volatile oil, and those of B. betulina give 4.25 per cent. of resin and 1.45 per cent. of volatile oil; so that B. serratifolia would seem to be the least active of the species. (P. J., xxi, 1890.)
Barosma Eckloniana Barth., 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 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., lxv, 506, 787) a small semi-solid volatile oil having the odor of peppermint. Recently a new buchu has appeared on the market, the leaves resembling very closely those of Barosma scoparia E. and Z. (Perf. & Ess. Oil Rec., 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 are lanceolate or narrowly linear, about 4 cm. in length, yellowish-green and very acute at the summit. They furthermore do not contain any oil canals at the base of the teeth. (For description of many other adulterants, see Holmes, P. J., 1910, lxxxv, p. 464.)
Properties.—Buchu leaves are officially described as follows:
"Short Buchu.—Rhomboidally oval or obovate; from 9 to 25 mm. in length and from 4 to 13 mm. in breadth; summit obtuse, and recurved; margin somewhat serrate or finely dentate with an oil gland at the base of each tooth; the base more or less wedge-shaped; color varying from vivid green to yellowish-green, occasionally a few olive-gray leaves; glandular-punctate; both surfaces papillose; under surface longitudinally striate; texture coriaceous; petiole 1 mm. in length; odor and taste characteristic, aromatic and mint-like.
"Long Buchu.—Linear-lanceolate, from 2.5 to 4 cm. in length and from 4 to 6 mm. in breadth; summit somewhat rounded or truncate with an oil gland at the apex; margin sharply serrate and glandular; otherwise resembling Short Buchu.
"Stems in both Short and Long Buchu about 1 mm. in diameter, yellowish-green or brownish-red, cylindrical, longitudinally furrowed, with prominent leaf-scars nearly opposite to each other giving the stems a jointed character. The yield of ash does not exceed 4 per cent." 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 near the margin. Transverse section exhibits in epidermis cells containing yellow sphere-crystals; inner walls of these cells thick and rich in mucilage. Odor and taste strong and characteristic." Br.
The leaves of B. crenulata 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. The leaves of the Empleurum serrulatum sometimes occur mixed with buchu leaves occasionally constituting the bulk of the parcel. They are to be distinguished by their acrid taste and peculiar odor and by being longer and narrower than any buchu leaf, with a sharp-pointed apex, parallel sides, and coarse denticulation. Further, according to Holmes, when the leaf of a Barosma is held up to the light the lateral veins appear straighter, longer, and more strongly developed than in the leaves of the Empleurum. John C. Umney (P. J., March, 1895) finds that the leaves of the latter contain 0.64 per cent. of a peculiar volatile oil. There is no reason to believe that they possess the therapeutical properties of buchu. Holmes enumerated a number of plants used in South Africa as substitutes. (See P. J; 1900, 70.)
Flückiger obtained from B. betulina 1.56 per cent. of volatile oil, which had the odor of peppermint rather than of buchu, and deviated the plane of polarization considerably to the left. On exposure to cold it furnished a camphor, which, after resolution in alcohol, crystallized in needle-shaped forms. After repeated purification in this manner, the crystals of Barosma camphor, or diosphenol, C10H16O2, have a peppermint odor; they fuse at 85° C. (185° F.) and begin to sublime at 110° C. (230° F.). After fusion they again solidify only at 50° C. (122° F.). Barosma camphor is abundantly soluble in carbon disulphide. The crude oil from which the camphor had been separated had a boiling point of about 200° C. (392° F.), quickly rising to 210° C. (410° F.), or even higher. The oil which distilled between these temperatures, rectified over sodium, gave approximately the formula C10H16O. (Pharmacographia, 2d ed., p. 109.) Spica examined B. crenulata and found the volatile oil to differ from that obtained by Flückiger from B. betulina; the solid body was similar to diosphenol, but upon analysis gave the figures C10H16O2, and hence is regarded by Spica as an oxycamphor. The liquid portion was a greenish-yellow oil, having a pleasant odor and a pungent, peppermint-like taste; by fractioning, it was separated into a portion isomeric with borneol, resembling thymol in odor and taste, to which the name of dioscamphor was given. A substance extracted by alcohol from the residue after the removal of the oil Spica named diosmin. (P. J., 1885, p. 106.) The results of Spica were confirmed by Shimoyama (A. J. P., 1888, p. 624), who made several simple derivatives of diosphenol and then prepared from it, by prolonged digestion with alcoholic potash, coolie acid, C10H18O3 + H2O, forming white crystalline needles, melting at 96° to 97° C. (204.8°-206.6° F.), and a compound to which he gave the name diolalcohol. Wayne's experiments (A. J. P., 1876, p. 19) appear to indicate that the oil also contains a substance capable of being converted into salicylic acid. J. M. Maisch believed that buchu leaves do not contain salicylic acid, although the stearopten of the oil gives a blackish color with ferric chloride. (A. J. P., July, 1881.) 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. The short leaved buchu was found by P. W. Bedford to yield an average of 1.21 per cent. of volatile oil; while the long leaved, though more highly valued in the market, gave only 0.66 per cent., showing its great inferiority in strength. (Proc. A. Ph. A., 1863, p. 211.)
Uses.—Buchu, originally employed by the Hottentots, has long since come into general use. Its activity 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, hence the remedy is of no value in dropsies, but the oil affects very decidedly the mucous membrane of the genito-urinary tract. The remedy is useful in diseases of the urinary organs, such as gravel, chronic catarrh of the bladder, morbid irritation of the bladder and urethra; diseases of the prostate, and retention or incontinence of urine from a loss of tone in the parts concerned in its evacuation. It should be given when the inflammation is not severe, but when it is in that condition of chronicity requiring oil of turpentine, tincture of cantharides, or other stimulant diuretics. An infusion (one ounce in a pint of boiling water) may be given in the dose of one to two fluid-ounces (30-60 mils), but the best preparation is the fluidextract.
Dose, one-half to one drachm (2.0-3.9 Gm.).
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.