72. Nasturtium officinale, R. Br.

The medicinal plant Cheiranthus Chieri, Linn is a member of the Brassicaceae or Cruciferae (mustards) family. This page includes its habitat, botanical descption, medicinal uses (eg., Ayurveda), chemical constituents and history of use in modern and ancient India.

Index in Flora of British India (Hooker): 1.133.

English:—The Water-cress.

Ver:—Piriya halim (Kumaon).

Habitat:—Rohilkhand, Punjab (N. India). Found near all hill-stations, but probably introduced. Simla in ditches. Ceylon, found naturalized at Kandy (Trimen).

Botanical description:—An aquatic.

Stem: creeping and floating, much branched.

Leaves: pinnate, the upper with 3-7 pinules and a terminal one, the lower cut into 3 repand segments.

Flowers: white, in short racemes.

Petals: longer than the sepals.

Pods: ⅓—1 in., stalked, spreading or bent upward; seeds small, 2-seriate.

Medicinal uses:—Used as a salad, on account of its appetizing and anti-scorbutic properties.

The essential oil consists chiefly of phenylethylenethiocarbimide, C₆H₅. CH₂.CH₂.N: CS, which was identified by converting it into the thiocarbamide. The glucoside from which these are derived, is named ‘gluconasturtiin,’ and is regarded as having the constitution—

CH₂Ph.CH₂.N.C(S.C₆H₁₁0₅).O.SO₃K+x;H₂O, but could only be obtained as a syrup; by decomposition with silver nitrate, it gives ‘silver nasturtiate,’ CH₂Ph.CH₂.N:C(SA_g).O.S0₃A_g+2H₂O, which also forms a crystalline compound with 2NH₃, but loses this at ordinary temperatures.

When acted on by sodium thiosulphate, silver nasturtiate gives a clear solution which probably contains the sodium salt, but soon decomposes into sodium sulphate and the thiocarbamide, which can then be extracted with ether. J. Ch. S. 1899 A I. 930.

From this plant phenylethylthiocarbimide, CH₂Ph.CH.NCS is obtained.

Silver nasturtiate is soluble in ammonia in the presence of ammonium nitrate, but is precipitated by nitric acid, and is decomposed by sodium thiosulphate into phenylethylthiocarbamide and sodium sulphate. When an attempt was made to prepare an additive compound of the silver salt with ammonia, it was found that some of the silver was replaced at the same time by ammonium. It is noteworthy that the seeds do not contain an appreciable quantity of any enzyme capable of hydrolysing the glucoside. J. Ch. S. 1900. A I. 49.