Mustasa is widely distributed in the settled areas of the Philippines, in towns, near houses, etc., planted and spontaneous. It was certainly introduced from the Asia, and is now pantropic in distribution, occurring also in some temperate regions.
The plant is an erect, branched, smooth annual, 0.4 to 1 meter in height. The leaves are oblong-obovate to oblong lanleocate, 5 to 15 centimeters long, or in some cultivated forms much larger, thin, irregularly toothed or subentire, the lower ones sometimes being lobed or pinnatifid. The flowers are yellow and 6 to 8 millimeters long. The pod is ascending, linear-lanceolate, 1.5 to 3 centimeters long, and somewhat contracted between the seeds, and the beak is seedless.
The leaves are eaten in the Philippines as a green leafy vegetable, either fresh or pickled in brine. Marañon shows that the leaves are excellent sources of calcium, phosphorus and iron. Hermano and Sepulveda claim that they are a good source of vitamin B.
According to Sanyal and Ghose the seeds contain an oily substance, “the essential oil of mustard,” which is the active principle. Pure mustard oil has a pale-yellow color with a faint odor of mustard and a very faintly pungent taste. Dymock, Warden, and Hooper obtained from mustard a crystallizable substance which they termed sinnigrin, from its analogy to sinalbin.
According to Sanyal and Ghose, externally, a plaster of mustard applied to the skin is a powerful irritant, rebefacient, and vesicant. When applied to the unbroken skin, it produces a sensation of warmth followed by a severe burning pain, and thus acts as a counterirritant. It is used externally to relieve pain of pleurodynia, pleuritis, hepatitis, etc. In an inflammatory condition of the viscera, it is very largely used as a counterirritant. Applied as a plaster, mustard soothes the pain in gastralgia, colic, neuralgia, lumbago, etc. In hiccoughing and vomiting it is applied over the epigastrum in the form of a plaster with great benefit. A plaster applied to the nape of the neck is very useful in cerebral congestion. Severe headaches, common colds, and febrile condition especially in children, are greatly relieved by a mustard foot-bath. To check infantile convulsions the patient is immersed in a mustard bath (a table-spoonful of mustard in a gallon of warm water). A mustard hip-bath is vey useful as an emmenagogue and is largely used to induce menstruation when it has been suppressed by any cause. Mustard poultices prove highly serviceable in cases of febrile and inflammatory diseases, internal congestions, and spasmodic, neuralgic and rheumatic affections. The pure fresh oil is a stimulant and mild counterirritant when applied externally; as such it is very useful in mild attacks of sore throat, internal congestion and chronic muscular rheumatism. The oil combined with camphor, forms an efficacious embrocation in muscular rheumatism, stiff-neck, etc. Gaius and Hooper say that the oil is used as an embrocation and is applied to the skin in eruptions and ulcers. The seeds are used as a poultice in gout and inflammation, according to Macmillan.
Sanyal and Ghose state that taken internally in small doses as condiment, mustard causes a sense of warmth in the stomach and stimulate the secretion of gastric juice, sharpen the appetite and promote digestion. When taken in large doses it acts as an irritant to the gastric mucous membrane and causes vomiting. It is very largely used as an emetic in narcotic poisoning (dose 1-4 teaspoonfuls in a tumbler of warm water). In cases of poisoning it is especially valuable on account of its reflex stimulant effects. Mustard oil is largely used in Bengal for culinary purpose
Other names : Sinapsis integrifolia West. Brassica juncea F.-Vill, Sinapsis juncea Blanco, Sinapsis brassicata Blanco,
Brassica orientalis Blanco
Sinapsis Sinensis Blanco source: Medicinal plants of the Philippines by eduardo Quisimbing