Oil of cajuput is obtained by distillation from the leaves and twigs of Melaleuca Leucadendron, Linn. (N.O. Myrtaceae), and various allied species indigenous to Upper India, the islands of the Malay Archipelago, Northern Australia, etc., the oil being distilled in the Molucca Islands, and imported by way of Batavia and Singapore. It is also official in the U.S.P. It occurs as a green to bluish-green, oily liquid, having an agreeable camphoraceous odour, and an aromatic, bitter, camphoraceous taste. Specific gravity, 0.919 to 0.930 (0.915 to 0.925 at 25°). Rotation, 0° to -4°. The green colour of the oil is due to contamination with copper; it can be removed by redistillation, or by shaking the oil with a concentrated solution of tartaric acid. The presence of turpentine as an adulterant lowers the specific gravity of the oil, as also does the abstraction of cineol.
Soluble in all proportions of alcohol; in 80 per cent. alcohol (1 in 1); often gives clear solutions with 70 per cent. alcohol (1 in 3 to 5).
Constituents.—The principal constituent of the oil is cineol, C10H18O, which should be present to the extent of 45 to 55 per cent. (U.S.P., not less than 55 per cent.), as determined by the phosphoric acid process (see Oleum Eucalypti). Solid terpineol, C10H18O, is also present, as well as its acetic acid ester; l-pinene, C10H16; and several aldehydes, such as valeric, butyric, and benzoic.
Action and Uses.—Oil of cajuput, when applied externally, acts as a stimulant and mild counter-irritant. It is applied to inflamed and rheumatic joints, diluted with 2 parts of olive oil of turpentine liniment. Internally, it has the typical action of a volatile oil and is antispasmodic; it is administered on sugar or as Spiritus Cajuputi to relieve flatulent colic. It has also been given internally in chronic rheumatism.
Dose.—1/2 to 2 decimils (0.05 to 0.2 milliliters) (1 to 3 minims).
- Spiritus Cajuput, B.P.—SPIRIT OF CAJUPUT.
- Oil of cajuput, 10; alcohol, sufficient to produce 100. Spirit of cajuput is used as a stimulant and antispasmodic in flatulent colic, etc. Dose.—3 to 12 decimils (0.3 to 1.2 milliliters) (5 to 20 minims).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.