Oleum Ajowan. Br. Ajowan Oil.
Related entry: Ajowan
"Ajowan Oil is the oil distilled from the fruit of Carum Copticum, Benth. and Hook. f." Br.
Under the name of ayowan, ajwain, ajwan, and other vernacular appellations, the fruit, of the Carum Ajowan Bentley (C. Copticum Benth. and Hook. f.) are largely used in India as an aromatic. They resemble in size the fruits of the ordinary parsley and are of a grayish-brown color and have a tubercular surface with five prominent ridges to each mericarp. The odor and taste resemble that of thyme. These fruits yield from 4 to 6 per cent. of an agreeably aromatic volatile oil. Ajowan oil is "colorless, with an odor and taste resembling thyme. Specific gravity 0.910 to 0.930. Optical rotation +10 to +2°. When 10 millilitres with 100 millilitres of solution of sodium hydroxide in a flask with a narrow graduated neck are heated on a water-bath, well shaken, and allowed to stand, the uncombined oil, cooled to 15.5° C. (60° F.), measures not more than 6 millilitres (presence of not less than 40 per cent. of thymol)." Br.
This oil, besides containing thymol, contains a terpene and also the cyclic hydrocarbon cymene.
The oil of ajowan is one of the most important commercial sources of thymol. Its medicinal virtues are due entirely to this ingredient.
Dose, one-half to five minims (0.03-0.3 mil).