This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
The unexpanded flowers of Eugenia aromatica (Linne) O. Kuntze (nat. ord. Myrtaceae).
Molucca Islands; cultivated in tropical countries.
About 15 mm. long, dark brown, consisting of a sub-cylindrical, solid and granular calyx-tube, terminated by four teeth, and surmounted by a globular head, formed of four petals, which cover numerous curved stamens, and one style. Cloves emit oil, when scratched, and have a strong, aromatic odor, and a pungent, spicy taste.
The chief constituents are - (1) Oleum Caryophylli (see below), 18 per cent. (2) Eugenin C10H12O2, a crystalline body. (3) Caryophyllin, C10H16O, a neutral body isomeric with Camphor.
Cloves are contained in Vinum Opii, Tinctura Rhei Aromatica, and Tinc-tura Lavandulae Composita.
Dose, 5 to 30 gr.; .30 to 2.00 gm.
A volatile oil distilled from Cloves.
A pale yellow, thin liquid, becoming darker and thicker by age and exposure to the air, having a strongly aromatic odor of Cloves, and a pungent and spicy taste. Sp. gr., 1.060 to 1.067.
The chief constituents are - (1) Eugenol (Synonym. - Eugenic Acid), C10H12O2, 85 per cent., which chemically resembles Phenol, and forms permanent Salts with Alkalies. This is also found in Oil of Pi-menta. (2) A terpene (Caryophyllene), C15H24.
Dose, 1 to 5 m.; .06 to .30 c.c.
Oil of cloves is a typical example of a volatile oil the most important actions of which are exerted in the stomach.
When rubbed into the skin it is stimulant, rubefacient, irritant, and counter-irritant, and gives rise to considerable vascular dilatation. At first it causes a sensation of tingling and pain, which afterwards is replaced by local anaesthesia. It is a parasiticide and antiseptic.
Mouth. - In the mouth, oil of cloves produces the same effects as on the skin: there is a burning sensation accompanied by vascular dilatation and an increased flow of saliva, and followed by local anaesthesia. Cloves stimulate the nerves of taste, and being volatile and aromatic, those of smell also; by both these means taste is sharpened.
Stomach. - The stimulant effect of cloves is experienced here. The vessels are dilated, peristalsis is accelerated, the secretion of gastric juice is excited, and as cloves are pleasant and aromatic, they do not ordinarily produce nausea; consequently the appetite is increased. The combined effect of these actions is to aid digestive processes - therefore oil of cloves is stomachic; and to facilitate the expulsion of gas - thus it is carminative. The stimulation of the gastric nerves to a slight extent reflexly affects the heart in the same way as alcohol; therefore the rate and force of the pulse are moderately increased.
Intestines. - Here likewise oil of cloves dilates the vessels, and stimulates the secretion and the muscular coat of the intestine; consequently colicky pains due to irregular contraction of it are relieved, and flatus is expelled.
Circulation. - Oil of cloves is readily absorbed from the intestine, circulates in the blood, and is said to increase the number of white corpuscles. It may, to a slight extent, stimulate the heart directly, but the greater part of the stimulation of the heart excited by it is reflex from the stomach. It is credited with the power of arresting painful spasmodic contractions in various parts of the body. It can, as we have seen, do this in the intestine, and possibly it may have to a slight extent the same action in the bronchial tubes, heart, etc. This causes it to be called antispasmodic.
Mucous membranes. - Like other volatile oils it is excreted by the kidneys, skin, bronchi, and genito-urinary tract, and in passing through these structures will act as a stimulating disinfectant to their secretion; but oil of cloves is never used for these purposes.
Oil of cloves is too expensive for frequent external application, but on account of its local anaesthetic effect it has been used for neuralgia. It is employed to give a pleasant scent to liniments.
The oil is sometimes dropped into decayed teeth to relieve pain. Cloves are frequently employed in cookery for their taste, and because they stimulate the appetite and aid digestion. The oil or infusion B. P., 1 to 40 may be used medicinally as a stomachic, as a carminative, as an anti-spasmodic, or to relieve colicky pains in indigestion. It will be noticed that oil of cloves is sometimes combined with preparations of scam-mony, of castor oil, and of colocynth. This is to prevent the griping these purgatives might otherwise cause.