Buchu leaves (Buchu, U.S.P.; Short Buchu; Round Buchu) are obtained from Barosma betulina, Bart. and Wendl (N.O. Rutaceae), a small shrubby plant indigenous to Cape Colony. The leaves are collected while the plant is flowering and fruiting, then dried and exported. The leaves vary from 12 to 20 millimetres in length; they have a characteristic rhomboid-obovate outline, a sharply denticulate margin, almost glabrous surface, and a blunt, strongly recurved apex. Numerous oil glands are distributed throughout the lamina of the leaf, especially near the indentations in the margin. The odour is strong and characteristic, more marked when the leaves are crushed, and the taste is strong and aromatic. When fresh, the leaves have a bright pale green colour, but this changes to yellow on keeping. In addition to the official "short " or "round " buchu, two other varieties of the drug are imported, viz., "long" buchu and "crenate" buchu. Long buchu leaves (B. serratifolia, Willd.. may be distinguished by their greater length (2.5 to 3.0 centimetres), linear lanceolate shape, serrate margin, and truncate apex; they contain numerous oil glands, one being situated in the truncate apex. The constituents are similar to those of the official variety, with the exception that they contain no diosphenol; as this is considered to be an important constituent, long buchu leaves have been excluded from the British Pharmacopoeia. Crenate buchu leaves (B. crenulata, Hook.. are rather broader than the long buchu, varying in outline from lanceolate to oval-oblong. They yield about 1.6 per cent. of volatile oil, which, like that of short buchu, contains diosphenol. Leaves of other species of Barosma are occasionally imported and offered as buchu, but the official variety is easily distinguished by the size and characteristic shape of the leaves.
Constituents.—Buchu leaves contain about 1.3 to 2 per cent. of volatile oil which, on cooling, deposits about 30 per cent. of diosphenol, C10H16O2, a crystalline and optically inactive substance, boiling at 232° with partial decomposition; other constituents of the oil are a hydrocarbon, C10H18, boiling at 174° to 176°, and a ketone, C10H18O, the latter possessing a pure peppermint-like odour, and probably identical with laevogyrate menthone. The drug also contains mucilage, diosmin and yellow sphero-crystals of hesperidin. It yields about 4 per cent. of ash on incineration.
Action and Uses.—Buchu is antiseptic and slightly diuretic; it is used principally in inflammatory conditions of the urinary organs as cystitis, pyelitis, vesical irritation, and gonorrhoea. The drug is used as infusion, tincture, or liquid extract. The infusion contains the demulcent mucilage of the freshly broken leaves. The liquid extract is a more concentrated preparation than the tincture, and is to be preferred when a small proportion only of alcohol is desired. Buchu is prescribed with diuretics and genito-urinary antiseptics, notably the benzoates, formamine, cubebs, etc.
- Extractum Buchu Liquidum, B.P.C.—LIQUID EXTRACT OF BUCHU. 1 in 1.
- Contains the volatile oil and alcohol-soluble constituents of the leaves in greater concentration than in Tinctura Buchu. It may be prescribed in place of the latter when a minimum of alcohol is desired, with fresh infusion of buchu. Dose.—3 to 12 decimils (0.3 to 1.2 milliliters) (5 to 20 minims).
- Fluidextractum Buchu, U.S.P.—FLUIDEXTRACT OF BUCHU.
- Buchu, in No. 60 powder, 100; a mixture of alcohol, 3, and water, 1, sufficient to produce 100. Average dose.—2 mils (30 minims).
- Infusum Buchu, B.P.—INFUSION OF BUCHU.
- Buchu leaves, freshly broken, 5; distilled water, boiling, 100. Infusion of buchu is a common vehicle for diuretics, urinary antiseptics, and sedatives. Dose.—30 to 60 mils (1 to 2 fluid ounces).
- Infusum Buchu Concentratum, B.P.C.—CONCENTRATED INFUSION OF BUCHU.
- A product closely resembling infusion of buchu is obtained by diluting 1 part of this preparation with 7 parts of distilled water. Dose.—4 to 8 mils (1 to 2 fluid drachms).
- Mistura Buchu Composita, B.P.C.—COMPOUND BUCHU MIXTURE.
- Each fluid ounce contains about 20 grains of potassium citrate, and 15 grains of tincture of hyoscyamus, with a sufficient quantity of infusion of buchu. This mixture is a diuretic and urinary sedative employed in cystitis, catarrh of bladder, nervous retention and incontinence of urine. Dose.—15 to 30 mils (1/2 to 1 fluid ounce).
- Tinctura Buchu, B.P.—TINCTURE OF BUCHU.
- Buchu leaves, in No. 20 powder, 20; alcohol (60 per cent.), sufficient to produce 100. Tincture of buchu is used as a diuretic and urinary antiseptic. Dose.—2 to 4 mils (1/2 to 1 fluid drachm).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.