6. CORYDALINE.
§ 420. Corydaline (C22H28NO4) is an alkaloid discovered by Wackenroder (1826) in the tubers of Corydalis tuberosa; crystallised in the cold and away from light, out of a mixture of absolute alcohol and ether, corydaline forms colourless, flat, prismatic crystals, which quickly turn yellow on exposure to light or heat. Pure corydaline changes colour at about 125°, softens at about 133°, and melts finally at 134° to 135°. It dissolves in ether, chloroform, carbon disulphide, and benzene, but not so readily in alcohol. It is almost insoluble in cold water, and but slightly soluble in boiling water. Water precipitates it from a solution in alcohol. It is also soluble in dilute hydrochloric and sulphuric acids. It gives a precipitate with potassium iodide if a solution of the hydrochloride be used. The precipitate crystallises out of hot water in clusters of short lemon-yellow prismatic crystals, and has the formula of C22H28NO4HI. Corydaline platinochloride has the composition of (C22H28NO4)2H2PtCl6, containing Pt 16·94 per cent., and 2·44 per cent. of N.—Dobbie & Lauder, Journ. Chem. Soc., March 1892, 244.
Corydaline in large doses causes epileptiform convulsions. Death takes place from respiratory paralysis.
V.—The Aconite Group of Alkaloids.
§ 421. The officinal aconite is the Aconitum napellus—monkshood or wolfsbane—a very common garden plant in this country, and one cultivated for medicinal purposes. Many varieties of aconite exist in other regions, which either are, or could be, imported. Of these the most important is the Aconitum ferox, a native of the Himalayan mountains, imported from India.
All the aconites, so far as known, are extremely poisonous, and it appears probable that different species contain different alkaloids. The root of A. napellus is from 2 to 4 inches long, conical in shape, brown externally, and white internally. The leaves are completely divided at the base into five wedge-shaped lobes, each of the five lobes being again divided into three linear segments. The numerous seeds are three-sided, irregularly twisted, wrinkled, of a dark-brown colour, in length one-sixth of an inch, and weighing 25 to the grain (Guy). The whole plant is one of great beauty, from 2 to 6 feet high, and having a terminal spike of conspicuous blue flowers. The root has been fatally mistaken for horse-radish, an error not easily accounted for, since no similarity exists between them.
§ 422. Pharmaceutical Preparations of Aconite.—The preparations of aconite used in medicine are—
Aconitine, officinal in all the pharmacopœias.