BOTANICAL CHARACTERISTICS.—A shrubby evergreen, with hard wood, covered with a smooth, gray bark. Leaves opposite, ovate-lanceolate, coriaceous. Petals 4, globular in bud, afterward spreading, whitish, aromatic. Ovary 2-celled; fruit a large, elliptical berry.
SOURCE.—The original habitat of the clove tree was the Molucca Islands, but they have been introduced into other East Indian Islands, into Zanzibar (which now forms the principal source), and into Cayenne. They are picked singly while green and are dried in the sun. Commercial: There are several varieties, as Molucco, Sumatra, and South American, the latter being rather inferior.
DESCRIPTION OF DRUG.—Cloves are about 15 mm. (⅗ in.) long, of a dark brown or reddish-brown appearance; the calyx tube is long, nearly cylindrical, crowned with the four stiff teeth (clasping the unexpanded corolla); corolla of four lighter colored, unexpanded petals, forming a hollow ball on the top of the calyx-tube, inclosing the numerous curved stamens and the single style; the ovary is inferior, situated near the top of the calyx-tube, and consists of two cells, each containing many ovules. A cross-section of the lower part of the calyx-tube under the microscope shows a thin outer layer surrounding a darker zone; this outer layer contains a double ring of oil cells; the inner darker zone contains an outside circle of about thirty fibrovascular bundles, with a larger bundle running through the center. Odor highly aromatic, especially when scratched; taste pungent and aromatic, followed by slight numbness.
Powder.—Characteristic elements: See Part iv, Chap. I, B.
CONSTITUENTS.—About 18 per cent. of volatile oil, 17 per cent. of tannin, a little fixed oil, gum, resin, etc. Two crystalline principles have been separated, caryophyllin, C10H16O, white, odorless, and tasteless, resinous, and eugenin, C10H12O2, isomeric with eugenol of the volatile oil, soluble in boiling alcohol and ether, as is also caryophyllin, but differing from the latter in turning red with nitric acid. Water extracts the volatile oil with scarcely any of the pungency of taste. Ash, not exceeding 8 per cent.
Preparation of Caryophyllin.—Treat ethereal extract of cloves with water, collect precipitate, and purify with ammonia.
ACTION AND USES.—Stimulant and carminative, used mostly as a synergist. Dose: 5 to 10 gr. (0.3 to 0.6 Gm.).
- Tinctura Lavandulae Composita
- (0.5 per cent.) Dose: ½ to 2 fl. dr. (2 to 8 mils).
- Tinctura Rhei Aromatica.
371a. CARYOPHYLLI FRUCTUS.—The ripe fruit, or Mother Cloves, resembles cloves in appearance, but is thicker and somewhat lighter in color and less aromatic; the corolla is absent, but the calyx-teeth still adhere.
371b. OLEUM CARYOPHYLLI.—OIL OF CLOVES. A pale yellowish-brown, thin liquid, becoming reddish-brown on exposure. It has a specific gravity of 1.060 and boils at about 250°C.; slightly acid; taste aromatic and hot; odor characteristic, aromatic. Oil of cloves consists of two oils-one lighter than water, the other heavier; the light oil, caryophyllene, C15H24, sp. gr. 0.91, is a pure hydrocarbon, and is thought to be inactive; the heavy oil is a phenol-like liquid termed eugenol, or eugenic acid, C10H12O2, sp. gr. 1.064 to 1.070
ACTION AND USES.—Used for the same purposes as cloves, more commonly, however, for introduction into an aching, carious tooth. Dose: 1 to 5 drops (0.065 to 0.3 mil)