Oleum Lavandulae Florum (U. S. P.)—Oil of Lavender Flowers.
Related entry: Lavandula.—Lavandula
"A volatile oil distilled from the fresh flowers of Lavandula officinalis, Chaix (Nat. Ord.—Labiatae). It should be kept in well-stoppered bottles, in a cool place, protected from light"—(U. S. P.).
Preparation.—Oil of lavender is distilled in France, from wild-growing, in England, from cultivated flowers. Distillation in France is effected by means of portable copper stills, in which the flowers are heated with water by direct fire, wood being used as fuel. The stills are carried to the fields where the flowers grow, because it is believed that the flowers deteriorate upon transportation. (In this connection, see an excellent illustration of such a distillerie ambulante in Gildemeister and Hoffmann, Die Aetherischen Oele, p. 785.) In stationary distilleries, the oil is obtained by distillation with steam. The yield is 1 pound of oil from 200 pounds of fresh flowers. Schimmel & Co. obtained from dried French flowers a yield of 1.2 per cent, from dried German flowers, 2.8 per cent. All lavender oils were indiscriminately termed oil of spike in former centuries (see Related Oils).
Description.—The official oil is described as "a colorless or yellowish liquid, having the fragrant odor of lavender flowers, and a pungent and bitterish taste. Specific gravity, 0.885 to 0.897 at 15° C. (59° F.). It is soluble in all proportions in alcohol (distinction from oil of turpentine), and in three times its volume of a mixture of 3 volumes of alcohol and 1 volume of water (distinction from, and absence of, oil of turpentine); it is also soluble in glacial acetic acid. With an equal volume of carbon disulphide it forms a turbid mixture. The alcoholic solution of the oil is neutral or slightly acid to litmus paper. When heated on a water-bath, in a flask provided with a well-cooled condenser, the oil should yield no distillate having the characters of alcohol"—(U. S. P.). The oil is optically laevo-rotatory (-3° to -10°). Upon exposure to the air it has been observed to absorb oxygen to the amount of about 120 volumes in 4 ½ months.
Oil of lavender is distinguished from all other oils of the natural order Labiatae by the quick and violent fulmination which takes place with iodine when about 0.1 Gm. of dry iodine is placed on a watch-glass and about 4 to 6 drops of the oil are brought in contact with it. Oil of lavender shares this property with oils of turpentine, lemon, orange peel, bergamot, spike, etc. A number of other oils, e. g., peppermint, cajuput, rue, etc., do not react in this manner, and this difference in behavior toward iodine, may sometimes be useful in detecting adulterations. (See classification of oils along this line in Hager's Handbuch der Pharm. Praxis, Vol. II, 1886, p. 565.)
Chemical Composition.—French lavender oil, according to Bertram and Walbaum (1892), and Schimmel & Co. (1893 and 1898), consists of large quantities of linalool (C10H18O, or CH3.C[CH3]:CH.CH2.CH2.C[CH3]OH.CH:CH2), l-linaloyl-acetate (30 to 45 per cent), butyrate, and probably propionate and valerianate; traces of pinene and cineol, and geraniol. Contrary to the statements of older observers, no camphor is present in true oil of lavender. The esters are the carriers of the aroma. English lavender oil, according to Semmler and Tiemann (1892), and Schimmel & Co. (1894), contains limonene, l-linalool, l-linaloyl acetate (7 to 10 per cent), a sesquiterpene, and appreciable quantities of cineol. (For method of determining the quantity of linaloyl acetate in lavender oils, see Power, Essential Oils, p. 20.) Large amounts of cineol in lavender oil indicate adulteration by oil of spike; pinene, by oil of turpentine.
Action, Medical Uses, and Dosage.—Oil of lavender possesses stimulant and carminative properties, and is sometimes administered in hysteria, nervous debility, and headache. Its fragrance renders it an important article in perfumery, in which it is principally used. Its dose is from 1 to 6 drops.
Related Oils.—OIL OF SPIKE. The broad-leaved variety of lavender (Lavandula Spica, De Candolle. furnishes the Oil of spike; it is not so fragrant as the preceding oil, and has a camphoraceous odor. Its specific gravity is 0.905 to 0.920; optical rotation, +3° (Schimmel & Co.). It is chiefly used in the manufacture of varnishes for artists, in painting on porcelain, and in veterinary practice. With 3 volumes of 70 percent alcohol at 20° C. (68° F.), according to Power (Essential Oils), it should produce a clear solution (absence of turpentine). It contains camphor (Kane, 1838), cineol (10 per cent), pinene (?), camphene, linalool, borneol, and possibly geraniol and terpineol.
OIL OF LAVANDULA STOECHAS, Linné.—Distills between 180° and 245° C. (356° and 473° F.); specific gravity, 0.942; odor, rosemary-camphor; known constituent, cineol.
OIL OF LAVANDULA DENTATA, Linné.—Distills almost entirely between 170° and 200° C. (338° and 392° F.); specific gravity, 0.926; known constituent, cineol.