The ripe seeds of Brassica alba (Linné), Hooker filius et Thompson (Sinapis alba, Linné) (Nat. Ord. Cruciferae). Asia and South Europe; cultivated. Dose (emetic), 1 to 3 drachms, with plenty of water.
Common Names: White Mustard, Yellow Mustard.
Principal Constituents.—A bland, fixed oil, average of 25 per cent; the glucoside sinalbin, the most important constituent, and myrosin, an enzyme which converts sinalbin into an acrid, and other bodies. Volatile oil of mustard is not obtained from white mustard.
Description.—A yellowish or light, brownish-yellow powder, odorless and mildly pungent and acrid to the taste. Dose, 1 to 3 drachms (as an emetic).
The ripe seeds of Brassica nigra (Linné), Koch (Nat. Ord. Cruciferae). Asia and southern Europe; cultivated. Dose (emetic), 1 to 3 drachms.
Common Names: Black Mustard, Brown Mustard.
Principal Constituents.—Fixed oil of mustard (average of 35 per cent); sinigrin (a glucoside) and myrosin, which in the presence of water and distillation converts the former into glucose, a potassium salt, and Volatile Oil of Mustard (Oleum Sinapis Volatile), (see below) an oil not derived from white mustard.
Description.—A pale-brown or greenish-brown powder, having an acrid, pungent taste, and developing, when moistened, a pungent and irrespirable odor. Dose, 1 to 3 drachms (as an emetic).
Preparation.—Emplastrum Sinapis, Mustard Plaster. Powdered black mustard deprived of its fixed oil mixed with solution of rubber and spread upon paper or other fabric. It is to be moistened with tepid water before being applied.
Derivative.—Oleum Sinapis Volatile, Volatile Oil of Mustard. An oil derived from black mustard or prepared synthetically and consisting largely of Allyl Isothiocyanate. A colorless or pale-yellow liquid having a very pungent and irrespirable odor and an acrid taste. The greatest caution should be taken when smelling this liquid; and it should not be tasted except when greatly diluted. Dose, 1/12 to 1/4 drop. There is no justification for its internal use.
Specific Indications.—External. Deep-seated pain and inflammations; vomiting from gastric irritability; and repressed secretion.
Internal. Emetic for poisoning by narcotics.
Action and Toxicology.—Volatile oil of mustard is an extremely diffusible and penetrating irritant, quickly exciting heat and burning pain through its dilating action upon the peripheral vessels and irritation of the sensory nerve endings. If too long applied it will blister, and cause inflammation, sloughing and deep ulceration; and not infrequently gangrene. To a degree local anesthesia is produced in some instances and the patient is then not aware of the possible destruction of tissue. Removed in time only induration is caused, followed sometimes by desquamation. Mustard applied in the same manner acts similarly but more slowly and with gradually increased intensity, as the volatile oil is but slowly formed from the moistened powder by the action of its ferment myrosin. The local action of mustard may stimulate reflex cardiac and respiratory activity in sufficient force to arouse one from an attack of fainting. Internally, mustard is a stimulating condiment and appetizer, and excites gastric activity and promotes digestion. If the amount be large, however, it is intensely irritant and promptly causes vomiting. This is not attended by depression, however, owing to the fact that both the breathing and circulation are stimulated by its reflex action upon the respiratory centers and the heart. Overdoses may induce acute gastritis, and if long continued chronic gastric catarrh. The volatile oil is an intense irritant poison, producing intense burning pain and destruction of tissue. Profound depression, renal hyperaemia, and insensibility precede death.
Therapy.—External. The mustard plaster and the sinapism (mustard poultice) are popular with physicians and the laity as rubefacients and counterirritants to relieve deep-seated pain and inflammation, check vomiting, reestablish suppressed urine, excite and restore menstruation, to arouse from insensibility in narcotic poisoning, syncope and asphyxia, and as a derivative generally. For this purpose they should be applied temporarily only and their effects carefully watched. Sometimes they act best when applied a little remote from the actually involved tissue, and they are necessarily so used when the internal organs are the seat of disease. For the purposes named the mustard plaster or sinapism may be applied to the chest and the abdomen in acute inflammation of the viscera, to the epigastrium and spine to check persistent vomiting from gastric irritability, and in gastralgia, gastritis, flatulence, to the abdomen in colic, over the loins in suppression of urine, lumbago and backache, to the nape of the neck in congestive headache and cerebral congestion, to the spine, legs, and soles of the feet to arouse from apoplexy, stupor, and coma, to the praecordial region in syncope, and locally to the areas involved in myalgia, neuralgias, muscular rheumatism, and inflammations of the joints. They should be used with great care upon children and debilitated individuals. Never more than one fourth mustard and three fourths white or rye flour should be employed in either, and the strength of the poultice can be regulated better in this manner than by using the ready prepared plaster. However, for general purposes the plaster, mustard leaves or papers, are most convenient, always ready for immediate use, and quickly and cleanly applied, first dipping them in water. It must be remembered that they are exceedingly energetic and usually stronger than a domestically prepared poultice. When necessary to use extra precaution, and in children, it is best to interpose a moistened layer of thin fabric between the skin and the application. When long and gentle action is desired, about one-twentieth part of mustard may be incorporated into flaxseed or other poultices. A blanket wrung from hot mustard water is sometimes used to restore retrocession of eruption in the exanthems, but special care should be had in scarlet fever, lest the already endangered kidneys be damaged. It should only be used as a last resort in this disease, but is less liable to do harm in measles. Warm water increases the activity of mustard applications; and the smarting sensation arising from the local use of mustard may be mitigated by sponging the parts with cold water, or spraying with ether.
Internal. The only rational use for mustard internally is to cause emesis in cases of narcotic poisoning. Besides acting as a prompt emetic, there is the added value of reflex stimulation of the heart and breathing organs, and consequently no depression. It should not be used for irritant or corrosive poisons. Its employment would seem rational in food poisoning (bromatotoxism) when there is depression of the nervous system and no irritation or gastro-intestinal inflammation present, provided there is still poisonous food in the stomach. As an emetic, from one to four teaspoonfuls may be administered in plenty of luke-warm water. It acts promptly and thoroughly, except in cases where the vomiting apparatus is paralyzed. In such instances the stomach pump or lavage tube should be used.