The active principles of the oleander are separated by digestion of the leaves with alcohol of 50 per cent., and precipitating the alcoholic extract with lead acetate and ammonia. The first precipitate is yellow, and is probably composed of a tannin-like substance; the next precipitate is white, consisting of the lead compound of neriin. The precipitates are filtered off, and the filtrate concentrated; nerianthin, after a while, separates in light flocks, and the filtrate from this contains some of the other products.
§ 559. Neriin or Oleander Digitalin.—Neriin is, in the presence of much free mineral acid, precipitated by potass-bismuth iodide, a reaction first pointed out by Marmé,[591] as useful in the isolation of the helleborins; or it may be precipitated by tannin, and then the precipitate decomposed by dissolving in alcohol, and evaporating it to dryness with zinc oxide on the water-bath. It is next extracted by absolute alcohol, and precipitated by the addition of much ether. The further purification consists of resolution in alcohol, and fractional precipitation by ether. If, however, the potass-bismuth iodide process is used, the liquid must be acidified strongly with sulphuric acid, and the precipitate washed with diluted sulphuric acid. The precipitate may be decomposed by baryta, filtered, and the filtrate freed from baryta by carbon dioxide; the filtrate from this contains neriin with baric iodide; it is therefore treated with silver sulphate, then again with baryta, next with carbon dioxide, and also with SH2 to get rid of the last trace of silver.
The filtrate will also contain some oleandrin which, by evaporating slowly in a vacuum, separates gradually in the form of a clear, resinous mass. It can be filtered off, and the neriin then may be precipitated pure by fractional precipitation. Its physiological action is the same as that of digitalein.
[591] Zeitschr. f. rat. Med. (3 R.), Bd. xxvi., S. 1, 1866.
§ 560. The nerium oleander has several times caused grave symptoms of poisoning, and they have usually fairly agreed with those produced by foxglove. For example, Maschka[592] relates the case of a boy, two years old, who ate two handfuls of the nerium oleander. The effects commenced in ten minutes, the child was uneasy, and vomited. In six hours a sleepy condition came on; the face was pale, the skin cold, the pupils contracted, and the pulse slow and irregular. After the sickness the boy woke up, but again fell asleep, and this occurred frequently; coffee was given, which appeared to do good. The pulse was intermittent. On the following day the child was still ill, with an intermittent pulse, frequent vomiting, feebleness, sleeplessness, and dilatation of the pupil; there was no diarrhœa, on the contrary, the bowels were confined. On the third day recovery followed.
[592] Vierteljahrsschrift f. gericht. Med., Bd. ii., No. 17, 1860. Brit. and For. Med. Chir. Review, vol. xxvi. p. 523, 1860.