Oleum Cubebae, B.P. Oil of Cubebs.
Related entries: Cubeb
Oil of cubebs is obtained by steam distillation from coarsely ground cubebs, the fruit of Piper Cubeba, Linn. (N.O. Piperaceae), a plant indigenous to Java, Sumatra, and Borneo, and apparently also cultivated in those islands. It is also official in the U.S.P. (Oil of Cubeb). It occurs as a light green or bluish-green liquid, having the characteristic odour, and warm, camphoracous taste of cubebs. The oil may be colourless, in which case the last portions of the distillate, which are blue, have been withheld. The colour of the oil is not due to the presence of copper, as frequently supposed, but to this blue fraction, the nature of which is, so far, unknown. Specific gravity, 0.910 to 0.930 (0.905 to 0.925 at 25°); rotation, -25° to -40°. Oil distilled from old cubebs (which contains the cubeb camphor) can be recognised by immersing a piece of potassium or sodium in it, when the metal loses its lustre and becomes covered with a crust, whereas with an oil from the fresh cubebs the metal is not attacked. This oil is seldom adulterated. Not more than 10 per cent. should distil below 250°, and at least 75 per cent. should distil between 250° and 280°.
Soluble in alcohol (1 in 18); and in all proportions of absolute alcohol.
Constituents.—The constituents of the oil are mainly, if not wholly, terpenes and sesquiterpenes. Dipentene, C10H16, a laevorotatory terpene (rotation, -35.5°), presumably pinene or camphene, and two sesquiterpenes, one identical with cadinene, C15H24, are present. Cubeb camphor, in oil distilled from old cubebs, appears to be a crystalline sesquiterpene alcohol, derived from the sesquiterpenes by oxidation, having the formula C15H25OH. It is laevorotatory, crystallising in rhombic forms, and melting at 65°. It is somewhat unstable, decomposing, when kept over sulphuric acid, into sesquiterpene and water.
Action and Uses.—Oil of cubebs is employed internally as a stimulating antiseptic to the bronchial and genito-urinary mucous membranes, in chronic bronchitis, gonorrhoea, and cystitis. It is excreted by the bronchioles, kidneys, and skin. The oil may be administered as an emulsion or in capsules. It is inhaled from hot water in chronic bronchitis. Its action resembles that of copaiba.
Dose.—3 to 12 decimils (0.3 to 1.2 milliliters) (5 to 20 minims).
- Vapor Cubebae, B.P.C.—CUBEB INHALATION. 1 in 12 ½ .
- Quantity sufficient for one inhalation, 4 mils (1 fluid drachm), to be added to 600 mils (1 pint) of water at 60°. Used in chronic bronchitis.