Upon distillation with water, the roots and seeds of Raphanus sativus, L. (Ger. Rettich, fam. Cruciferae) yield a small amount1) of a colorless oil which contains sulphur and is heavier than water. It possesses the taste, but not the odor, of radish2).
Bertram and Walbaum15) distilled 75 kg. of comminuted Spanish radish with water vapor. They obtained an aqueous distillate of an unpleasant odor. When shaken out with petroleum ether, a few grams of an oil were obtained that did not react with ammonia. Gadamer4) repeated the experiment with similar results. The distillate, which had an unpleasant odor of cabbage, contained traces of sulphur but was free from mustard oil. He concluded that the volatile oil of radish does not distil without decomposition with water vapor and he therefore extracted freshly grated Spanish radish with ether. In this manner he obtained a brownish oil that had the characteristic odor and taste of radish. Upon standing for some time, crystals separated which probably consisted of raphanol (See below). The oil reacted with ammonia, but no crystalline thiourea could be obtained.
That Spanish radish oil results from the hydrolytic action of an enzyme upon a glucoside was proved by Gadamer in the following manner. A Spanish radish cut into thin slices was dropped into strong alcohol in order to prevent the action of the enzyme on the glucoside. When dried, the slices no longer produced the radish odor with water. This odor, however, was produced when some myrosin was added.
*) For the yield comp. footnote 1 on p. 528, No. 20 - 21. 8) Pless, Liebig's Annalen 58 (1846), 40. 8) Journ. f. prakt. Chem. II. 50 (1894), 560. 4) Arch, der Pharm. 2:57 (1899), 520.
Upon the distillation of the root of Raphanus niger, H. Moreigne1) obtained traces of oil and 0,0025 p.c. of a crystalline substance which melted at 62° and which he named raphanol, or, since it possessed the properties of a lactone, raphanolid.
Raphanolid contains neither nitrogen nor sulphur. According to elementary analysis and molecular weight determination, the formula C20H5804 should be assigned to it. When boiled with acetic acid anhydride, it yields an acetyl derivative melting at 122 to 123°.
The liquid portion of radish oil contains sulphur but no nitrogen. It does not combine with ammonia.