Oleum Pimentae (U. S. P.)—Oil of Pimenta.

Botanical name: 

Related entry: Pimenta (U. S. P.)—Pimenta

A volatile oil distilled from Pimenta officinalis, Lindley. "It should be kept in well-stoppered bottles, in a cool place, protected from light"—(U S. P.).
SYNONYMS: Oil of allspice, Oil of pimento.

Preparation, Description, and Tests.—When unripe and sun-dried allspice or pimento berries are bruised and distilled with water, they yield a volatile oil to the extent of from about 3 to 4.5 per cent. The ripe fruits are nearly odorless. The oil is heavier than water, its lowest density being given as 1.024 (Schimmel & Co.'s Report, April, 1899). The official oil is "a colorless, or pale-yellow liquid, having a strong, aromatic, clove-like odor, and a pungent, spicy taste. It becomes darker and thicker by age and exposure to the air. Specific gravity, 1.045 to 1.055 at 15° C. (59° F.). With an equal volume of alcohol it forms a clear solution which is slightly acid to litmus paper. It also forms a clear solution with an equal volume of glacial acetic acid, and a nearly clear solution with an equal volume of carbon disulphide. When mixed with an equal volume of a concentrated solution of sodium hydrate, it forms a semisolid mass. If 2 drops of the oil be dissolved in 4 Cc. of alcohol, and a drop of ferric chloride T.S. be added, a bright green color will be produced; and if the same tests be made with a drop of diluted ferric chloride T.S., prepared by diluting the test-solution with four times its volume of water, a blue color will be produced changing to green, and soon becoming yellow. If 1 Cc. of the oil be shaken with 20 Cc. of hot water, the water should not give more than a scarcely perceptible acid reaction with litmus paper. If, after cooling, the liquid be passed through a wet filter, the clear filtrate should produce, with a drop of ferric chloride T.S., only a transient grayish-green, but not a blue or violet color (absence of carbolic acid)"—(U. S. P.).

Chemical Composition.—This oil contains over 60 per cent of the heavy eugenol (C6H3.C3H5[OH][OCH3]), the chief constituent of oil of cloves (which see), and a sesquiterpene of the composition C15H24, boiling at 255° C. (491° F.).

Action, Medical Uses, and Dosage.—Oil of pimenta is stimulant and aromatic, and may be used for similar purposes as the other oils of like character, in doses of from 2 to 10 drops.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.