This section is from the book "Materia Medica And Therapeutics: An Introduction to the National Treatment of Disease", by John Mitchell Bruce. Also available from Amazon: The pharmacology and therapeutics of the materia medica.
Sinapis - Mustard. - The seeds of Sinapis Nigra, and Sinapis Alba; also the seeds reduced to powder, mixed.
Characters of the Powder. - Greenish-yellow, of an acrid bitterish oily pungent taste, scentless when dry, but exhaling when moist a pungent penetrating peculiar odour, very irritating to the nostrils and eyes. Impurity. - Starch; a decoction cooled should not be made blue by tincture of iodine.
Substances resembling black mustard: Colchicum seeds, which are larger, lighter, and not quite round.
Composition. - The seeds of sinapis nigra contain: (1) about 35 per cent. of a bland fixed oil. When this has been removed by expression, and the powdered mustard mixed with water and distilled, there is obtained (2) the officinal volatile oil, Oleum Sinapis, C4H5NS. This is a colourless or pale yellow body, nearly insoluble in water, of intensely penetrating odour, burning taste, and blistering action on the skin. As the seeds and powder of the mustard are devoid of these irritant properties, the oil cannot exist ready formed in them, but is developed by a decomposition of their constituents. On the addition of water to the black mustard, its most important principle, potassium myronate or sinigrin (C10H18NKS2O10), a compound of potassium with an acid glucoside, myronic acid, is broken up by another constituent, myrosin, a ferment, into volatile oil of mustard, potassium sulphate, and sugar, thus: K,C10H18NS2O10 = C4H5NS + KHSO4 + C6H12O6. Sinapis alba also contains the fixed oil. It does not, however, yield the volatile oil, but a substance with allied properties, called sulpho-cyanate of acrinyl, C8H7NSO, by a similar decomposition of its constituents, sinalbin, C30H44N2S2O16 (in place of potassium myronate) and myrosin, thus: C30H44N2S2O16 = C8H7NSO + C16H13NO5,H1SO4 (disulphate of sinapin) + C6H12O6 (glucose).
Oleum Sinapis. The oil distilled with water from the seeds of Sinapis nigra after the expression of the fixed oil. Solubility, 1 in 50 of water; readily in spirit and ether.
Cataplasma Sinapis. Mustard in powder, linseed meal, and boiling water.
Charta Sinapis. Made with guttapercha solution.
Externally. - When applied to a limited area of skin mustard acts quickly (1) as a rubefacient and nervous stimulant, causing redness, heat, and severe burning pain. (2) This effect is speedily followed by loss of sensibility in the part to other impressions, and relief of previous pain. (3) The prolonged application of the charta or cataplasm causes vesication by the production of local inflammation. Neighbouring and deeper parts, and viscera in vascular communication or intimate nervous relation with the blistered area, may thus have their circulation relieved. The heart, blood pressure, respiration, and nervous centres generally are stimulated by the first application of mustard to the skin; soothed during the stage of anaesthesia, and relief of pain; and depressed in the third stage, especially if the vesication be severe through neglect. Applied to the whole or a large part of the surface of the skin in the form of a bath, mustard dilates the cutaneous vessels, and thus relieves the blood pressure in the viscera.
In the form of poultice or paper, mustard is extensively used as a readily available, convenient, and rapid means of relieving local pain, stimulating the internal organs, and pro-ducing counter-irritation, with evanescent and mild after-effects. It is applied to relieve the pains of muscular rheu-matism (lumbago, etc.); neuralgia in any part of the body; the inde6nite pains in the chest in chronic disease of the lungs or heart; and colic, gastralgia, and other forms of distress in the abdomen. As a cardio-vascular and respiratory stimulant, a large sinapism may be applied to the calves or soles in syncope, coma, or asphyxia, whether from disease or from poisoning. The counter-irritant effect of mustard is chiefly used in inflammation of the throat, larynx, bronchi, lungs, pleura, and pericardium; sometimes in abdominal diseases; frequently, and with success, in morbid conditions of the stomach, and persistent vomiting from any cause. Diffused through a warm bath it is a popular "derivative" in cerebral congestions, headache, and at the onset of colds and febrile diseases in children. A mustard sitz bath may stimulate menstruation if taken at the period.
Internally. - Mustard produces a familiar pungent impres-sion on the tongue and olfactory organs, a sense of warmth in the stomach, and an increase of relish and appetite. The cir-culation in the gastric wall is also stimulated, but it is remark-able that the effect of mustard on the circulation in the stomach is much less powerful than that on the skin. In full doses it is emetic, with a rapid stimulant action, and little subsequent depression.
Mustard is used internally chiefly as a condiment. As an emetic, from one to four teaspoonfuls may be given stirred up with a tumblerful of warm water in cases where other emetics are not available, or have failed, especially in poisoning by narcotics such as opium.
Armoraciae Radix - Horseradish Root. - The fresh root of Cochlearia Armoracia. Cultivated in Britain.
Characters. - A long cylindrical, fleshy root, half an inch to one inch in diameter, expanding at the crown into several very short stems. It is internally white, and has a pungent taste and smell.
Substances resembling Horseradish: Aconite root, which is short, conical, darker, and causes tingling when chewed.
Composition. - Horseradish yields, along with other constituents, a volatile oil, C4H5SN, closely allied to the volatile oil of black mustard, and formed, like it, by decomposition of a more complex principle by means of a ferment.
Spiritus Armoraciae Compositus. - 1 in 8, with orange-peel, nutmeg, and spirit. Dose, 1 to 2 f1.dr.
Horseradish has been used in domestic medicine as a counter-irritant, but is most familiar as a pleasant condiment, possessing much the same properties as mustard. The compound spirit is a flavouring and carminative agent.