Boldo leaves are obtained from Peumus Boldus, Molina (N.O. Monimiaceae), a dioecious evergreen tree indigenous to the central provinces of Chili. The leaves are ovate or elliptical in shape, 4 to 8 centimetres long, shortly petiolate, greyish-green in colour, coriaceous, and brittle. The margin is entire and slightly revolute, the apex obtuse. The midrib and veinlets are prominent on the under surface. Both surfaces bear numerous emergences, each of which is crowned with a group of one-celled, thick-walled hairs, which, however, are very readily broken off. The transverse section is sharply characterised by the presence of a well-marked hypoderma below the upper epidermis, by numerous oil-cells in the mesophyll, and by the emergences bearing the hairs previously referred to. The drug has an aromatic odour and a pungent, camphoraceous, bitter taste. The leaves of Cryptocarya Peumus, Nees (N.O. Laurineae), which grows in the same districts as boldo, closely resemble boldo leaves; they may be distinguished by their darker colour, by the wavy margin, and by the absence of hairs.
Constituents.—The principal constituent of boldo leaves is about 2 per cent. of volatile oil (specific gravity, 0.915 to 0.945; optical rotation +2° 25' to -1° 40'; refractive index, 1.4777), in which, in addition to terpenes, terpineol. has been detected. The leaves also contain the bitter alkaloid boldine (0.1 per cent.), and the glucoside boldin or boldoglucin. They yield about 10; per cent. of ash.
Action and Uses.—Boldo leaves are employed in Chili and other South American countries for chronic hepatic congestion and as an aromatic tonic and diuretic in gonorrhoea, cystitis, and other bladder affections. Its diuretic and stimulant properties are apparently due to the volatile oil. The alkaloid, boldine, has been recommended for use as a hypnotic; also, in combination with calomel, in liver congestion. It has weak local anaesthetic properties. Boldoglucin, the glucoside of boldo, also possesses hypnotic properties, and has been given internally in capsules, 18 centigrams (3 grains) in each. Boldo is now used principally in the form of tincture, as a diuretic and supposed liver stimulant, but it should be noted that the functions of the liver cannot be stimulated or increased by any known drug; bile salts increase the flow of bile, but are not known to affect the other functions of the liver.
- Tinctura Boldo, B.P.C.—TINCTURE OF BOLDO. 1 in 10.
- Used as a diuretic. Dose.—1/2 to 2 1/2 mils (10 to 40 minims).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.