Ol. Cajup. [Cajuput Oil, Oil of Cajeput]
Related entry: Cajuput
"A volatile oil distilled from the fresh leaves and twigs of several varieties of Melaleuca Leucadendron Linné, especially the var. Cajeputi Roxburgh and the var. minor Smith (Fam. Myrtaceae). Preserve it in well-stoppered, amber-colored bottles, in a cool place." U. S. "Oil of Cajuput is the oil distilled from the leaves of Melaleuca Leucadendron, Linn., and other species of Melaleuca." Br.
Oleum Cajeputi; Essence de Cajeput, Huile volatile de Cajeput, Fr.; Cajeputol, G.; Essenza di Cajeput, It.; Esencia de Cayeput, Sp.; Kayuputieh, Mal.
It was long supposed that the oil of cajuput was derived only from Melaleuca Leucadendron, but it is now well established that it is derived chiefly from one or more varieties of this species. They are trees indigenous to upper India, the Islands of the Indian Ocean, Northern Australia, Queensland and New South Wales. (See The Volatile Oils, Gildemeister and Hoffmann.) It is possible, however, that the oil may also be obtained from different species of Melaleuca, as Stickel of Jena, succeeded in procuring from the leaves ofM. hypericifolia, cultivated in the botanical garden of that place, a specimen of oil not distinguishable from the cajuput oil of commerce, except by a pale-green color. (Ann. Pharm., xix, 224.) M. viridifolia and M. latifolia, large trees growing abundantly in the Island of New Caledonia, yield a volatile oil very analogous to the oil of cajuput.
Melaleuca Leucadendron Linné (M. Cajuputi Bumphius) grows with an erect but crooked stem, and scattered branches, the slender twigs of which droop like those of the weeping willow. The bark is of a whitish ash color, very thick, soft, spongy, and lamellated, throwing off its exterior layer from time to time in flakes. The leaves have short footstalks, are alternate, lanceolate, when young sericeous, when full-grown smooth, deep green, three- and five-nerved, slightly falcate, entire, from three to five inches long, from one-half to three-quarters of an inch broad, and when bruised exhale a strong aromatic odor. The flowers are small, white, inodorous, sessile, and disposed in terminal and axillary downy spikes, with solitary, lanceolate, three-flowered bracts. The filaments are three or four times longer than the petals, and both are inserted in the rim of the calyx. The oil is obtained from the leaves by distillation. It is prepared chiefly in Amboyna and Bouro, and is exported from the East Indies in glass bottles. The small proportion yielded by the leaves and the extensive use made of it in India render it somewhat costly.
Properties.—Cajuput oil is very fluid, transparent, of a fine green color, a lively and penetrating odor analogous to that of camphor and cardamom, and a warm, pungent taste. Upon rectification the green color disappears. It is very volatile and inflammable, burning without any residue. The sp. gr. varies from 0.914 to 0.9274. Its chief constituent has the formula C10H18O, and by repeated distillation over phosphoric oxide the hydrocarbon, C10H16, called cajuputene, can be obtained. The oil is, therefore, said to contain cajuputene hydrate, or cajuputol. The identity of cajuputol with cineol and eucalyptol from Eucalyptus Globulus in both chemical and physical properties was established by Wallach. in 1884 and by C. Jahns (A. J. P., 1885, 237.) It boils at 175° C. (347° F.). A second constituent of the formula C10H18O is the solid terpineol, which is present both in the free state and as acetic ester. A small amount of l-pinene and traces of aldehydes have been found, including valeraldehyde and benzal-dehyde. (Schimmel & Co's Report, April, 1897.) Oil of cajuput is "a colorless or yellowish liquid having a peculiar, agreeable, distinctly camphoraceous odor, and an aromatic, slightly bitter taste. It is soluble in 1 volume of 80 per cent. alcohol. Specific gravity: 0.912 to 0.925 at 25° C. (77° F.). Its optical rotation does not exceed -4° in a 100 mm. tube at 25° C. (77° F.)." U. S.
"Green or bluish-green. Agreeable, camphoraceous odor; taste aromatic, bitter and camphoraceous. Specific gravity 0.919 to 0.930; optical rotation not more than -4°; refractive index at 25° C. (77° F.) 1.460 to 1.467. When 10 millilitres of the Oil are mixed with 4 to 5 millilitres of syrupy phosphoric add in a vessel surrounded by a freezing mixture, and then pressed strongly in a piece of fine calico between folds of blotting-paper, the pressed cake, decomposed by warm water in a graduated vessel, yields an oily layer, which, on cooling to 15.5° C. (60° F.), measures not less than 4.5 millilitres (presence of not less than 45 per cent. of cineol)." Br,
The U. S. requires the oil to be colorless or yellow, but according to the Br. it has a greenish tint. When it is distilled, a light, colorless liquid first comes over, and afterwards a green and denser one. The green color has been ascribed to a salt of copper derived from the vessels in which the distillation is performed, and Guibourt obtained two grains and a half of copper oxide from a pound of the commercial oil. But neither Brande nor Gaertner could detect copper in specimens examined by them, and Lesson, who witnessed the process for preparing the oil at Bouro, attributes its color to chlorophyll or some analogous principle, and states that it is rendered colorless by rectification. Guibourt, moreover, obtained a green oil by distilling the leaves of a Melaleuca cultivated at Paris. A fair inference is that the oil of cajuput is naturally green, but that as found in commerce it sometimes contains copper, either accidentally present or added with a view of imitating or maintaining' the fine color of the oil. The proportion of copper, however, is not so great as to forbid the internal use of the oil, and the metal may be separated by distillation with water, or by agitation with a solution of potassium ferrocyanide. This statement as to the frequent occurrence of copper in the cajuput oil of commerce, though at the same time its presence is not desirable, has been confirmed by experiments by Edward Histed, who found copper in all of six specimens of the commercial oil, obtained from different sources. When redistilled, the oil became perfectly colorless, but after a few days' exposure to copper filings reassumed its green color. (P. J., 1872, p. 804.)
Oil of cajuput is said to be often adulterated with oils derived from other than the official species of Melaleuca, Oil of rosemary, and oil of turpentine, impregnated with camphor and colored with the resin of milfoil, are also said to be employed as adulterants. The best test, according to Zeiler, is iodine, which, after a moderately energetic reaction, with little increase of temperature and but a slight development of orange vapors, occasions immediate inspissation into a loose coagulum, which soon becomes dry, greenish-brown, brittle mass.
Uses.—This oil is highly stimulant, producing when swallowed, a sense of heat, with an increased fulness and frequency of pulse, and exciting in some instances profuse perspiration. It is much esteemed by the Malays and other people of the East, who consider it a panacea. Formerly the oil of cajuput was used internally in chronic rheumatism, low fevers, and various other complaints, but is rarely employed at present for its alterative effects. It is useful internally as a stimulating expectorant in chronic laryngitis and bronchitis, as a urinary antiseptic in cystitis, and as an anthelmintic especially against the round worm. Its most frequent uses, however, are externally in the treatment of various skin diseases. For this latter group of affections it is used for its anti-parasitic effect in such diseases as scabies, tinea versicolor, etc., and for its stimulating action in acne rosaceae, psoriasis, and other chronic conditions. It is also used externally as a counter-irritant in chronic rheumatism and other painful conditions. Like many other essential oils it relieves toothache if introduced into the hollow carious tooth.
Dose, from three to ten minims (0.2-0.6 mil).
Off. Prep.—Linimentum Crotonis, Br.; Spiritus Cajuputi, Br.; Linimentum Tiglii, N. F.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.