Gelsemii Radix, B.P. Gelsemium Root. Gelsemina, Gelseminae Hydrochloridum.
GELSEMII RADIX, B.P.
Gelsemium root (Gelsemium, U.S.P.) or yellow jasmine root consists of the dried rhizome and root of Gelsemium nitidum, Michaux, also known as G. sempervirens, Ait. (N.O. Loganiaceae), a climbing plant indigenous to the Atlantic and Gulf regions of the United States. The rhizome usually occurs in straight, nearly cylindrical pieces, 10 to 20 centimetres in length and 5 to 20 millimetres in thickness. In young pieces the outer layer is a brownish-violet cork, which becomes much furrowed during the subsequent growth of the rhizome, until in the older pieces it is yellowish-brown marked with purple reticulated lines. The fracture is woody and splintery; a smoothed section exhibits a very conspicuous radiate structure, narrow, yellowish wood bundles with small vessels alternating with straight, whitish medullary rays. In the cortex occasional silky bast fibres may be found; while the centre of the rhizome is usually occupied by a small pith. The root differs from the rhizome, which it otherwise closely resembles, in being of a uniform yellowish colour and somewhat tortuous; it is destitute of a pith and of bast fibres. Gelsemium has a bitter taste and a slight agreeable odour. Portions of the slender aerial stems are often attached to the rhizome, and may be recognised by their purple colour and abundant silky bast fibres; large pieces should not be present in the drug, as they are less active. The rhizome of Jasminum fruticans, Linn., is said to be collected in the place of gelsemium; it may be distinguished by the cells of the pith, which are thin-walled and full of starch, while those of gelsemium are thick-walled and empty.
Constituents.—The drug contains a crystalline alkaloid, gelsemine, and two amorphous alkaloids, gelseminine and gelsemoidine, together with essential oil, scopoletin, and a brown resin which yields pentatriacontane, emodin monomethyl ether, a phytosterol, ipuranol, and a mixture of palmitic, stearic, oleic, and linolic acids.
Action and Uses.—Gelsemium acts somewhat like conium, except that it paralyses the nerve centres first, and the motor nerve endings only after very large doses. It is used in migraine and neuralgia, especially neuralgia of the fifth nerve; also in rheumatic, ovarian, and uterine pain. The action of the drug is due to the alkaloids it contains. It should be used with care, as untoward symptoms sometimes result from comparatively small doses. Excessive doses cause giddiness, double vision, and loss of power, with slowing and subsequent stoppage of respiration. The tincture is most commonly used, and may be given in mixture form with the bromides or with butyl-chloral hydrate. Alcoholic extract of gelsemium is prescribed in pills, frequently with butyl-chloral hydrate. Applied to the eye, gelsemium produces dilatation of the pupil, lasting about two days, and some irritation. Its use as a mydriatic has been abandoned. A powdered alcoholic extract, named gelsemin, is given in pills, in doses of 3 to 12 centigrams (½ to 2 grains); it must be carefully distinguished from the alkaloid gelsemine. In cases of poisoning by gelsemium or its alkaloids, the stomach pump should be used or an emetic given, followed by a hypodermic injection of atropine and stimulants, employing artificial respiration if necessary.
Dose of the powdered root.—15 to 60 milligrams (¼ to 1 grain).
- Extractum Gelsemii Alcoholicum, B.P., 1885.—ALCOHOLIC EXTRACT OF GELSEMIUM.
- Gelsemium root, in No. 60 powder, 1 pound; alcohol, a sufficient quantity. Macerate the drug with 2 pints of alcohol for forty-eight hours, then transfer to a percolator and percolate with alcohol till exhausted. Recover most of the alcohol by distillation, and evaporate the residue to a mass of suitable consistence. This extract may suitably replace the extractive "gelsemin," the name of which renders it liable to be confused with the alkaloid gelsemine. Alcoholic extract of gelsemium, is often prescribed in pills, with butyl-chloral hydrate or quinine. Dose.—3 to 12 centigrams (½ to 2 grains).
- Fluidextractum Gelsemii, U.S.P.—FLUIDEXTRACT OF GELSEMIUM.
- Gelsemium in No. 60 powder, 100; alcohol (95 per cent), to 100. Prepared by percolation. Average dose.—5 centimils (0.05 milliliters) (1 minim).
- Tinctura Gelsemii, B.P.—TINCTURE OF GELSEMIUM.
- Gelsemium root, in No. 40 powder, 10; alcohol (60 per cent.), sufficient to produce 100. Prepare by the percolation process. Tincture of gelsemium is used chiefly in the treatment of neuralgia. In some people moderate doses cause double vision. Dose.—3 to 5 decimils (0.3 to 0.5 milliliters) (5 to 15 minims).
- Tinctura Gelsemii, U.S.P.—Similar to B.P.
C20H22N2O2 = 322.196.
Gelsemine, C20H22N2O2, is an alkaloid obtained from the root of Gelsemium nitidum, Michaux (N.O. Loganiaceae). It occurs in white, microscopic crystals. Melting-point, 178°. It has a strongly alkaline reaction. With concentrated sulphuric acid it gives a yellowish, and with concentrated nitric acid a green, colouration. Sulphuric acid with an oxidising agent gives a violet colouration, which becomes green after a while. Gelsemine must be distinguished from gelsemin, the resinoid prepared by extracting gelsemium root with alcohol and occurring as a powdered extract. It must also be carefully distinguished from amorphous gelsemine; it should be observed that Merck's "gelseminin" consists of crystalline gelsemine and not amorphous gelseminine.
Soluble with difficulty in water, more easily in alcohol, very easily soluble in ether or chloroform.
Action and Uses.—Gelsemine has been used in neuralgias, especially trigeminal. In large doses it produces convulsions in frogs, in the same way as strychnine, and afterwards it paralyses the motor nerve-endings, but it is almost devoid of this action in mammals. It is sometimes prescribed in pills or cachets, frequently in combination with butyl-chloral hydrate.
Dose.—½ to 2 milligrams (1/120 to 1/32 grain).
C20H22N2O2, HCl = 358.664.
Gelsemine hydrochloride, C20H22N2O2, HCl, is the hydrochloric acid salt of the alkaloid gelsemine. It occurs in the form of prismatic crystals, or as a white crystalline powder. Gelsemine hydrochloride must not be confused with gelseminine hydrochloride, which occurs as a yellowish, hygroscopic powder, soluble in water and in alcohol, is intensely poisonous, and is seldom used in medicine (see Gelsemina).
Soluble in water, but not readily soluble in alcohol.
Action and Uses.—The action and uses of gelsemine hydrochloride are the same as those of gelsemine.
Dose.—1 to 3 milligrams (1/60 to 1/20 grain).