Carui Fructus, B.P. Caraway Fruit. Carvonum, .
CARUI FRUCTUS, B.P.
Related entry: Oil of caraway
Caraway fruit (Carum, U.S.P.; Caraway) is the dried ripe fruit of Carum Carvi, Linn. (N.O. Umbelliferae), a biennial plant indigenous to, and cultivated in, Europe, chiefly in Holland. In the drug, as met with in commerce, the two mericarps of which the fruit consists are usually separate. They are curved and taper towards each end, dark brown in colour, glabrous, and traversed longitudinally by five yellowish filiform ridges. The transverse section is almost equilaterally pentagonal, and exhibits six small vittae, four on the dorsal and two on the commissural surface. The drug has an agreeable aromatic odour, due to the volatile oil it contains. The oil is distilled chiefly from Dutch, Norwegian and Russian fruits. The Dutch are small and dark brown in colour; English fruits, of which only a small quantity is produced, are of a brighter tint. Some varieties contain much impurity in the form of stalks, dust, dirt, etc. Good caraways yield about 6 per cent. of ash; the B.P. and U.S.P. limits are 8 per cent. Entire fruits are sometimes used for the distillation of the oil; in this case the whole of the volatile oil is not distilled off, and the yield is smaller, but the residual fruits may be dried and sold for various purposes. Such fruits may be recognised by their dark colour, shrivelled appearance, want of aroma, and low yield of aqueous extract (less than 15 per cent.).
Constituents.—The chief constituent of caraway fruit is 3.5 to 7 per cent. of volatile oil; they also contain fixed oil.
Action and Uses.—The aromatic properties of caraway fruit, due to its volatile oil, are utilised for combination with purgatives, as in Tinctura Sennae Composita and Pilula Aloes Barbadensis. Distilled caraway water is a useful remedy in the flatulent colic of infants, and is an excellent vehicle for children's medicines; when sweetened its flavour is agreeable.
- Aqua Carui, B.P.—CARAWAY WATER.
- Caraway fruit, 10; water, 200. Add the fruit to the water and distil 100. Used as a carminative and flavouring agent, Dose.—30 to 60 mils (1 to 2 fluid ounces).
- Aqua Carui Concentrata, B.P.C.—See under Oleum Carui.
Related entries: Carvacrol
C10H14O = 150.112.
Carvone, C10H14O, is a ketone contained in caraway, dill, and spearmint oils. That occurring in caraway and dill oils is dextrorotatory, that from spearmint oil is laevorotatory. Pure carvone is separated from the oil by fractional distillation, or may be obtained by passing sulphuretted hydrogen into an alcoholic solution of the oil saturated with ammonia gas; crystals of an addition compound, C10H14OH2S, are formed, purified by recrystallisation from methyl alcohol, and subsequently decomposed by alcoholic potash. It occurs as a thickish, colourless or slightly yellow, liquid, with an odour of caraway. Specific gravity, 0.963 to 0.966. Boiling-point, 224°. In a 100-millimetre tube it rotates the plane of polarised light 62° to the right. Pure carvone solidifies at low temperatures. It forms a liquid addition product with hydrochloric acid, and a solid compound with hydrobromic acid. Mixed with an equal volume of alcohol, it gives a violet colour with very dilute ferric chloride solution, the colour disappearing on adding excess of the reagent. Heated with sulphuric acid, hydrochloric acid, phosphoric acid, zinc chloride, or alkalies, it is converted into the isomeric carvacrol (C6H3CH3OHC3H7). Potassium permanganate oxidises it to oxyterpenylic acid (C8H12O5.. It differs from other ketones in not being converted into the corresponding alcohol on reduction.
It is miscible with all proportions of alcohol, soluble in 70 per cent. alcohol (1 in 2) and in 50 per cent. alcohol (1 in 20); carvone containing 2 per cent. of limonene will not form a clear solution under these conditions.
Action and Uses.—Carvone has the aromatic and carminative properties of oil of caraway.
Dose.—1/4 to 2 decimils (0.025 to 0.2 milliliters) (1/2 to 3 minims).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.