Botanical Source.—The oleander bush is an arborescent shrub, having branches ternately divided, and coated with an almost smooth bark of a grayish or greenish-gray color. The smooth, coriaceous, deep-green, almost sessile leaves, are in whorls of three; above, they are glossy; beneath, grayish or pale-green. They are linear-lanceolate, acuminate, entire, marked with delicate, feather veins, and about 4 to 6 inches long. The flowers are beautiful, and of a rose or white color, and waxy appearance.
History and Chemical Composition.—The leaves of this ornamental shrub, grow wild in northern Africa, western Asia, and the south of Europe. They have been used in the treatment of epilepsy, but without apparent benefit. All parts of the shrub are cardiac poisons. The acrid and bitter leaves of Nerium Oleander contain, according to Schmiedeberg (1882), three glucosids, namely: non-basic, amorphous, poisonous oleandrin, discovered by Leukowsky (1864), who believed it to be an alkaloid; nerein (neriin), considered by Schmiedeberg to be identical with digitalein (see Digitalis), and crystallizable nerianthin, free from nitrogen. (For details regarding the study of Oleander, see Husemann and Hilger, Pflanzenstoffe, 1884, p. 1331.)
From the bark of Nerium Oleander, E. Pieszczek (Archiv der Pharm., 1890, p. 352) isolated a new, poisonous, nitrogen-free glucosid, rosaginin, in the form of warty crystals, melting at 171° C. (339.8° F.), soluble in strong alcohol with neutral reaction, nearly insoluble in water, petroleum ether, chloroform and ether if free from alcohol. In addition were obtained, bitter, amorphous neriin, of Schmiedeberg, nitrogen-free, lemon-yellow, soluble in water and absolute alcohol with neutral reaction, insoluble in ether and petroleum ether, and producing a purple-violet coloration when dissolved in concentrated sulphuric acid and brought into contact with bromine vapor; a volatile oil of an unpleasant odor, and a crystallizable, fluorescent body occurring more pronouncedly in older bark, probably identical with umbelliferon. The oleander of Algeria, upon incision of the twigs, yields a poisonous exudate which is said to contain strophanthin (Amer. Jour. Pharm., 1899, p. 281). The flowers of the oleander are reputed to yield a poisonous honey. The exhalation of the flowers of oleander in bedrooms is said to have caused death (see Pieszczek, loc. cit.).
Action, Medical Uses, and Dosage.—According to Orfila, Kurzak, and others, all parts of the oleander plant are poisonous. From experiments upon birds and the lower animals, it was determined that both the voluntary and involuntary muscles were paralyzed by it, and the voluntary muscles were somewhat convulsed. When death ensues, respiration is first arrested and then the heart's action stops. The action of the active constituents has been compared to that of digitalis. Water in which oleander leaves have lain, is said to have caused the death of animals, and the flesh of fowls has been rendered sufficiently toxic to be fatal to man. Rats are said to be poisoned by the bark, and pediculi destroyed by a decoction of the leaves. In fatal cases, the heart has been found flaccid, and the larger venous trunks filled with a dark-colored blood. The chief therapeutic use that has been made of oleander, is in epilepsy, and it has been abandoned in that malady as useless. From its decidedly toxic power over the heart, it seems worthy of an investigation as a cardiac remedy. In fact it has been found to act well in valvular affections, rapidly slowing the heart's action, reducing the oedema, and relieving the dyspnoea. Some have preferred it to digitalis in atheromatous states. It is actively diuretic, and occasionally purges. The dose, in infusion or tincture, represents from 1 to 3 grains of fresh bark or, dried fruit.
Related Species.—Nerium odorum, Aiton (Nerium odoratum, Lamarck). India. Wild and cultivated. Closely resembles the preceding plant, but its flowers are fragrant, its leaves longer, and has a paracorolla which is fringed. Greenish, in 1881, isolated two toxic, bitter glucosids, and a fixed oil. Neriodorin is a yellow, tenacious, transparent varnish, soluble in chloroform, somewhat less in alcohol, and little soluble in water. According to Schmiedeberg, it is analogous to oleandrin, while neriodoriin is a lemon-yellow powder, insoluble in chloroform, but soluble in water and alcohol, and resembling neriin. Neither are dissolved by carbon disulphide, benzin or benzol.
Geissospermum laeve, Baillon.—A Brazilian tree known in its habitat as paó pereira. The bark is very bitter, and contains three alkaloids. Geissospermine (C19H24N2O2+H2O, O. Hesse, 1877), crystallizable, melting at 160° C. (320° F.), is insoluble in water and ether, not easily soluble in cold, but readily soluble in warm alcohol; soluble in concentrated sulphuric acid to a colorless liquid which soon turns blue; it is poisonous, and causes death by paralysis. Pereirine (C19H24N2O, O. Hesse), an amorphous alkaloid, soluble in alcohol, ether, chloroform, nearly insoluble in water. Nitric acid dissolves it with blood-red color which does not turn violet with stannous chloride (difference from brucine, see Nux Vomica). Large doses paralysis, fever, and death. Vellosine (C23H28N2O4, M. Freund and Fauvet, Jahresb. der Pharm., 1893, p. 513, and 1895, p. 449) is a well-crystallizable alkaloid, insoluble in water, soluble in chloroform, alcohol, warm benzol and petroleum benzin, partly soluble in ether. According to analysis by T. Peckolt (ibid., 1896, p. 40), the air-dried bark contains pereirine, 2.72 per cent; geissospermine, 0.125 per cent; wax, starch, resin, etc. The leaves, but not the bark, contained tannic acid. The bark is an antiperiodic also.
Parameria vulneraria, Radlkofer.—Philippine Islands. A climbing plant, the bark and leaves of which, when boiled in cocoanut oil, yield a peculiarly odorous, yellow substance known as Cebu balsam (Balsamo de Tagulaway). An aromatic resin, 3 per cent, and caoutchouc, 8.5 per cent, are yielded by the bark of the root (Zipperer, Archiv der Pharm., 1885, p. 817), The oily, yellow-white liquid is applied to wounds and cutaneous affections.
Thevetia yccotli, De Candolle (Cerbera thevetioides, Kunth).—The tree known in the Mexican Cordilleras as the joyote. It inhabits the damp, hot sections of the mountains. The fruit is applied to hemorrhoids. The seeds, which are known as joyote seeds, are very acrid and poisonous. A. Herrera (Amer. Jour. Pharm., 1877, p. 145) obtained, by pressure, 40 per cent, of a fixed oil, and a crystallizable, acrid glucosid which he called thevetosin. Merck (1894) isolated another glucosid which he named cerberid. It is a cardiac poison.
Thevetia neriifolia, De Candolle (Cerbera Thevetia, Linné).—West Indies. Bark of this shrub used as an antiperiodic. It yields the crystallizable glucosid thevetin, discovered by De Vrij. By treatment with diluted acids, it splits into sugar and a resinoid body, theveresin. Thevetin (C54H84O24) is bitter, odorless, soluble to some extent in cold water, more soluble in alcohol and acetic acid. Theveresin (C48H70O17) is a white powder, and is but slightly dissolved by hot water. Both principles are toxic. Thevetin is a cardiac, and to some extent a respiratory paralyzer. Its effects are practically identical with those of digitalin. Its identity with cerberin and tanghine has been questioned. The latter is the active constituent of the "Madagascar ordeal bean," from the Tanghinia venenifera; the former, the active constituent of Cerbera odallum, Gaertner. Thevetia ovata, De Candolle, and Thevetia cuneifolia, De Candolle, have properties similar to yccotli, and are known as narcisos amarillos and also as joyote. This bark is a drastic cathartic, and the fruit causes emesis.