Oleum Caryophylli. U. S., Br. Oil of Clove.
Ol. Caryoph. [Clove Oil, Oil of Cloves]
Related entry: Cloves
"A volatile oil distilled from the flower-buds of Eugenia Aromatica (Linné) O. Kuntze [Jambosa Caryophyllus. (Sprengel) Niedenzu] (Fam. Myrtaceae), and yielding not less than 82 per cent., by volume, of eugenol [C10H12O2 = 164.10]. Preserve it in well-stoppered, amber-colored bottles, in a cool place, protected from light." U. S. "Oil of Cloves is the oil distilled from Cloves." Br.
Huile volatile de Girofle, Fr. Cod.; Oleum Caryophyllorum, P. G.; Nelkenöl, Eugenol, G.; Essenza di garofani, It.; Esencia de clavo, Sp.
This oil is obtained by distilling cloves with water, to which it is customary to add common salt, in order to raise the temperature of ebullition and the water should be repeatedly distilled from the same cloves, in order completely to exhaust them, Scharling has found advantage from the application of superheated steam to the distillation of this oil. (P. J., xi, 469.) It is essential also to use the same water over and over again, in order to avoid loss by the solution of the ofl in the water. The product of good cloves is said to be about one-fifth or one-sixth of their weight. The oil was formerly brought from Holland or the East Indies, but since the introduction 'of the Cayenne cloves into our markets the reduced price and superior freshness of the drug have rendered the distillation of oil of clove profitable in this country, and the best now sold is of domestic extraction. The exportation of clove from Zanzibar in 1909 was over 20,000,000 pounds. We have been informed that from seven to nine pounds of clove yield to our distillers about one pound of the oil.
Properties.—Oil of cloves, when recently distilled, is very fluid, clear, and colorless (but becomes yellowish by exposure, and ultimately reddish-brown). It has the odor of cloves, a hot, acrid, aromatic taste, and a slightly acid reaction. Its sp. gr. is variously stated at from 1.034 to 1.061, the latter being given by Bonastre as the sp. gr. of the rectified oil.
"Oil of Clove is a colorless or pale yellow liquid, becoming darker and thicker by age and exposure to the air, having the characteristic odor and taste of clove. It is soluble in 2 volumes of 70 per cent. alcohol. Specific gravity: 1.038 to 1.060 at 25° C. (77° F.). Its optical rotation does not exceed -1° 10' in a 100 mm. tube at 25° C. (77° F.)
Oil of clove is one of the least volatile of the essential oils and requires for congelation a temperature from -17.8° to -20° C. (0° to -4:° F.). It is completely soluble in alcohol, ether, and strong acetic acid. Nitric acid changes its color to a deep red, and converts it by the aid of heat into oxalic acid. The same change to red is produced by nitric acid on morphine, but in this case the red is followed by yellow, which does not happen with the oil of clove. Besides, if to a solution of morphine with nitric acid a solution of chlorinated lime be added, and the mixture be exposed for some hours to the light, the solution of morphine will retain a straw color, while if oil of clove be treated in the same manner the color disappears. (Haselden, B. F. M. H., July, 1867, 265.) It is frequent adulterated with fixed oils, and sometimes with oil of pimenta and with copaiba. When pure, it sinks in distilled water. According to E. Scherer, these adulterations may sometimes be detected by attention to the specific gravity and the boiling point, pure oil of clove varying in specific gravity from 1.03 to 1.06, and boiling at from 240° C. (464° F.) to 255° C. (491° F.). According to Zeiler, its character of congealing entirely into a crystalline mass with the alcoholic solution of potassium hydroxide, losing at the same time its peculiar odor, affords a .sufficient criterion ef its purity. This, however, while included among the official tests, is not sufficient, the percentage of eugenol as determined by the official assay being now a requirement.
Oil of clove contains small amounts of vanillin, methyl alcohol and furfurol, but is mainly composed of an unsaturated phenol termed eugenol which is now an official product (see Eugenol) and its acetic derivative and a sesquiterpene caryophyllene. Eugenol acetyl salicylate hash also been reported. The U. S. Pharm. IX introduced an assay process for the eugenol content.
Eugenol, C10H12O2 (see p. 432), has been shown to be the methyl ether of allyl-dioxybenzene,
One of its most important reactions is its conversion into vanillin. For this purpose it is boiled with acetic anhydride, whereby aceteugenol is formed, which, oxidized in weak acid solution by potassium permanganate, yields acetvanillic acid, and this with weak potassium hydroxide solution is changed into vanillin, which is then extracted by acidifying and shaking up with ether. (See also Ph. Era, 1887, 444.) For the estimation of eugenol in the form of its crystalline benzoyl compound, see A. J. P., 1892, 26 and 508; also Schim. Rep., April, 1892, 28. The characteristic aromatic odor of oil of clove is due to methyl-amylketone, CH3.CO.C3H11, which has been isolated by the chemists of Schimmel & Co., and found to be present only in minute, quantity. (Ph. Bev., 1897, 115.)
Uses.—By virtue of its local irritant effect oil of clove stimulates peristalsis and is frequently a useful remedy in the treatment of flatulent colic. It is also an active local anesthetic and is a favorite remedy for toothache; for this purpose a small pledget of cotton is saturated with oil and inserted into the carious cavity. It is a powerful germicide, far exceeding phenol in activity, but is not frequently used for this purpose. Eugenol has been used internally in doses of forty-five grains (3 Gm.) per diem as an antiseptic antipyretic. Little, however, is known of its physiological action. According to Leubuscher (W. M. Bl., 1889) it is a feeble local anesthetic. Landis (T. G., 1909, xxxiii, 386) has used oil of clove as a stimulant expectorant in tuberculosis and bronchiectasis with good results.
Dose, from two to six minims (0.12-0.4 mil).
Off. Prep.—Elixir Cardamomi Compositum (from Compound Spirit), N. F.; Elixir Glycyrrhizae Aromaticum, N. F.; Nebula Aromatica, N. F.; Spiritus Cardamomi Compositus, N. F.