Oleum Sinapis Volatile. U. S., Br. Volatile Oil of Mustard.
Ol. Sinap. Vol. [Mustard Oil]
Related entry: Mustard
"A volatile oil produced synthetically or obtained from the seed of Brassica nigra (Linné) Koch (Fam. Cruciferae) (freed from fatty oil) by maceration with water and subsequent distillation. It yields not less than 92 per cent. of allyl isothiocyanate [C3H5SCN = 99.12]. The label must indicate whether the Oil has been made synthetically or obtained from black mustard. Preserve it in well-stoppered, amber-colored bottles, in a cool place, protected from light." U. S. "Volatile Oil of Mustard is the oil obtained by distillation from black mustard seeds, deprived of most of their fixed oil and macerated in water for several hours." Br.
Oleum Sinapis, Br. 1885; Oleum Sinapis Aethereum; Oil of Mustard; Huile volatile (Essence) de Moutarde, Fr.; Oleum Sinapis, P. G.; Senföl, Aetherisches Senföl, G; Essenza di senape, It.; Esencia de mostaza negra, Sp.
The volatile oil of mustard is usually obtained from seeds which have been deprived of their fixed oil by pressure. It is "a colorless or pale yellow, strongly refractive liquid, having a very pungent and irritating odor and an acrid taste. Great caution should be exercised in smelling this Oil. It should not be tasted except when highly diluted. Specific gravity: 1.013 to 1.020 at 25° C. (77° F.). It is optically inactive. The Oil distils completely between 148° and 154° C. (298.4°-309.2° F.), and both the first and last portions of the distillate have nearly the same specific gravity as the original Oil." U. S.
Will considers volatile oil of mustard to be allyl isosulphocyanate, CSNC3H5 (allyl isothiocyanate), it being related to oil of garlic, which is sulphide of allyl. It sometimes contains allyl cyanide and traces of carbon disulphide. (Chem. Gaz., Nos. 62 and 64.) It is the principle upon which black mustard seeds depend for their activity. Volatile oil of mustard was first produced artificially by Berthelot and S. de Luca, by treating allyl iodide, C3H5I, with an alcoholic solution of potassium sulphocyanate. It is now extensively manufactured artificially by this method. What first forms is allyl sulphocyanate, which is not identical with, but only an isomer of, mustard oil (allyl isosulphocyanate). But if the sulphocyanate be heated to its boiling point 161° C. (321.8° F.) the thermometer sinks rapidly to 150° C. (302° F.), because of the change into the isosulphocyanate, or mustard oil. This change also takes place spontaneously at summer temperature. A small quantity of carbon disulphide seems always to be produced at the same time. Allyl iodide is procured by treating glycerin with phosphorus iodide. According to Zeiler, the seeds yield from 0.33 to 0.63 per cent. of the oil. Will and Koemer in 1863 explained the occurrence of this allyl isosulphocyanate in mustard oil. It does not occur ready formed in the seeds, but is produced by the decomposition of a compound, sinigrin (potassium myronate), occurring there. This sinigrin, C10H18KNS2O10, is decomposed under the influence of myrosin, an albuminous ferment which is present, and yields as products of decomposition C3H5CNS (allyl isosulphocyanate), HKSO4 (acid potassium sulphate), and C6H12O6 (glucose). "The aqueous solution of myrosin coagulates at 60° C. (140° F.), and then becomes inactive; hence mustard seed which has been heated to 100° C. (212° F.), or has been roasted, yields no volatile oil, nor does it yield any if powdered and introduced at once into boiling
White mustard seeds yield different products. When deprived of fatty oil they yield to boiling alcohol colorless crystals of sinalbin, an indifferent substance readily soluble in cold water, but sparingly so in cold alcohol. According to Will, it breaks up under the action of myrosin into acrinyl sulphocyanate, C7H7O.CNS, sinapine sulphate, C16H25NSO9, and glucose, C6H12O6. This acrinyl sulphocyanate is a nearly colorless, non-volatile oil, and the rubefacient and vesicating principle of white mustard. Sinapine has not yet been isolated, but it is an unstable alkaloid.
Uses.—Oil of mustard is a powerful rubefacient, although liable to blister unless used with much caution. Diluted, either with alcohol or lard, it is used as a counter-irritant application in sprains, rheumatism and like conditions. It may employed in strengths of from two to four per cent.
The volatile oil of mustard has been employed as a substitute for the mustard plaster. For this purpose one part may be mixed with sixty parts of alcohol, and the mixture sprinkled, not too thickly, on piline or muslin, covered with waxed paper. It acts speedily and efficiently.
The oil is too pungent and irritating to be given internally.
Off. Prep.—Linimentum Sinapis, Br.; Linimentum Sinapis Compositum, N. F.; Spiritus Sinapis, N. F.