A. W. Hofmann3) prepared the oil of Nasturtium officinale, L. in the following manner: The aqueous distillate (600 kg.) of 600 kg. of herb, which had not been comminuted, was shaken out with petroleum ether. After evaporation of the petroleum ether from a paraffin bath at 140°, 40 g. = 0,066 p.c. of oil not absolutely free from petroleum ether remained. The oil did not have a cress-like odor; d18o1,0014; it began to boil at 120°, but the temperature soon rose to 200° and finally to 280°. After repeated fractionation, the bulk of the oil distilled at 261°. Its behavior towards alkali revealed its nature as a nitrile. The acid liberated from the alkali melted at 47°, and was phenyl propionic acid as proved by analysis. Hence the principal substance of the oil thus obtained is phenylpropionic acid nitrile, C6H5 • Ch2 • Ch2 • CN. In addition to this substance the oil contained hydrocarbons which may have been due to the petroleum ether used in its preparation.
1) Journ. de Pharm. et Chim. VI. 4 (1896), 10. - Bull. Soc. chim. HI. 15 (1896), 797.
2) Arch, der Pharm. 237 (1899), 518. - Berl. Berichte 32 (1899), 2335. 3) Berl. Berichte 7 (1874), 520.
From the higher boiling fractions beautiful dodecahedra separated. On account of the small amount of material these could not be further examined.
Utterly different results were obtained by Gadamer1) who distilled the carefully comminuted herb. He obtained an oil which separated at the bottom of the receiver and which had a strong mustard oil odor reminding of that of Spanish radish. Its identity with phenylethyl mustard oil was established by means of the thiourea melting at 135 to 136°2).
Water-cress contains a glucoside C15H20Kns2o9 + X H20 named gluconasturtiin, which has not yet been isolated. Enzymes hydrolyze it to glucose and phenyl ethyl mustard oil.
As in the case of the common cress, the deviating results obtained by Hofmann are due to the fact that he distilled uncomminuted herb, whereas Gadamer carefully comminuted his material to a pulp, in a meat grinder. Thus the glucoside and enzyme, which are deposited in different cells of the plant, are enabled to come into contact, producing the ordinary hydrolysis of the glucoside. When the entire herb is distilled, the ferment is destroyed, the glucoside being exposed to the destructive influence of the hot water vapors.
In the water-cress H. Moreigne") found raphanolid.