Caryophyllum, B.P. Cloves. Eugenol.
Related entry: Oil of cloves
Cloves (Caryophyllus, U.S.P.) are the dried flower-buds of Eugenia caryophyllata, Thunb. (N.O. Myrtaceae), an evergreen tree indigenous to the Molucca Islands, and cultivated there, as well as on the Malay Peninsula, in Zanzibar and Pemba, Java, etc. As the buds develop they assume a green and then crimson colour, when they are collected and dried. During the drying the crimson colour changes to a reddish-brown. The dried buds are about 15 millimetres long, and of a rich, reddish-brown colour. Each consists of a fleshy sub-cylindrical lower portion crowned by four thick calyx teeth, and four yellowish-brown imbricated petals; the latter enclose numerous stamens and a short, thick style. A transverse section of the fleshy, lower portion exhibits numerous oil glands near the periphery. The calyx and petals also contain oil glands, but they are not so numerous. Cloves of good quality should have a strong aromatic odour and taste; they should be plump and of a bright reddish-brown colour, sink in water, and readily exude oil when indented. Cloves should not yield more than 7 per cent. (U.S.P., 8 per cent.) of ash. The stalks upon which the clove buds are borne are also collected and exported in considerable quantities. They are brown and woody, about 1 to 2 millimetres thick and 1 to 3 centimetres long. They yield about 5 or 6 per cent. of volatile oil, which is less agreeably aromatic than that of cloves, although resembling it in specific gravity (1.040 to 1.065, oil of cloves 1.045 to 1.070) and optical rotation ([α]D, = up to 1° 10', oil of cloves the same), and containing rather more eugenol. The nearly ripe fruits are also exported under the name of mother cloves (anthrophylli): they are dark brown ovoid, one-seeded berries, crowned by the remains of the calyx teeth. Mother cloves contain but little volatile oil. Both clove stalks and mother cloves have been used to adulterate ground cloves. The former may be detected by the presence of numerous characteristic, nearly isodiametric, sclerenchymatous cells; the latter by the large starch grains which the seeds contain. Blown cloves are those which have been collected after the petals have expanded; both the petals and the stamens have been broken off, leaving the thick portion of the clove crowned by the somewhat patent calyx teeth. Clove dust often consists largely of the broken stamens, etc.
Constituents.—The principal constituent of cloves is the volatile oil, of which they should contain from 15 to 20; per cent. They also contain gallotannic acid (13 per cent.) and a crystalline body, caryophyllin, which, however, is odourless, and appears to be a phytosterol.
Action and Uses.—Cloves are stimulating and carminative to the alimentary canal; they are used in flatulence, dyspepsia, and as adjuvants to other medicines. The medicinal properties of cloves are resident principally in the volatile oil, which may be given on sugar, or in capsules with menthol, peppermint, or creosote. The oil is used to flavour emulsions; and is a good carminative to correct, the griping action of purgatives, 2 centimils (0.02 milliliters) (⅓ minim) being sufficient in each pill. Fresh infusion of cloves contains the astringent matter as well as some of the volatile oil; the infusion and clove water are good vehicles for alkalies and aromatics. Oil of cloves is a powerful antiseptic and preservative; it is applied to decayed teeth as a local anaesthetic.
- Aqua Caryophylli, B.P.C.—CLOVE WATER.
- Cloves, 2.5; water, 200; distil 100.
- Infusum Caryophylli, B.P.—INFUSION OF CLOVES.
- Cloves, bruised, 2.5; distilled water, boiling, 100. infuse the drug in the water for fifteen minutes, in a covered vessel, and strain. Infusion of cloves is a useful vehicle for stimulant stomachics. It is carminative, slightly astringent, and antiseptic. Dose.—15 to 30 mils (½ to 1 fluid ounce).
- Infusum Caryophylli Concentratum, B.P.C.—CONCENTRATED INFUSION OF CLOVES.
- A product closely resembling infusion of cloves is obtained by diluting 1 part of this preparation with 7 parts of distilled water. Dose.—2 to 4 mils (½ to 1 fluid drachm).
C10H12O2 = 164.096.
Eugenol, C6H3C3H5OCH3OH, is a phenol found in oil of cloves, oil of pimento, and other oils. It is official in the U.S.P. It may be obtained by shaking oil of cloves with excess of a 5 or 10 per cent. solution of sodium hydroxide, drawing off the resulting solution of eugenol-sodium, washing it with ether and decomposing by means of diluted sulphuric acid. The eugenol which separates is washed with solution of sodium bicarbonate and finally distilled with steam or in vacuo. It occurs as a colourless or slightly yellow optically inactive liquid, with an odour of cloves and a pungent spicy taste. Specific gravity, 1.072 to 1.074. Boiling-point, 251° to 253°. It should be entirely and readily soluble in diluted solution of sodium hydroxide. It gives a blue colour on the addition of solution of ferric chloride to its alcoholic solution; on oxidation with potassium permanganate it yields vanillin. Eugenol should be preserved in well-stoppered bottles, protected from the light.
Soluble in all proportions of alcohol, ether, chloroform, or glacial acetic acid.
Action and Uses.—Eugenol is an antiseptic and is not toxic. It has some local anaesthetic properties and is a useful solvent of other local anaesthetics, such as pure cocaine, or erythrophloeine hydrochloride for use in dental practice. It is also used in combination with astringents as a mouth wash after tooth extraction. An antiseptic ointment of eugenol with hydrous wool fat has been used for eczema. Eugenol is administered, in the same manner as oil of cloves in phthisis, as a carminative and antiseptic.
Dose.—½ to 2 decimils (0.05 to 0.2 milliliters) (1 to 3 minims).
- Liquor Eugenolis et Thymolis Compositus, B.P.C.—COMPOUND SOLUTION OF EUGENOL AND THYMOL.
- Eugenol, 4; thymol, 1; tincture of calendula, 50; tincture of krameria, to 100. The addition of about 40 minims of this solution to half a pint of warm water produces an excellent mouth wash.