The Toxicity of Gelsemium.

Abstract

The rhizome and root of Gelsemium sempervirens, Linne, indigenous to North America, have long been used in medicine for their analgesic and antispasmodic properties and are actively poisonous. It is recorded that 0.8 cc. of the fluid extract proved fatal to a child of 3 years and many other cases of gelsemium poisoning are studied by Wormley, 1 Witthaus, 2 and others. Gelsemine, the principal alkaloid of gelsemium, was first investigated by Wormley, 3 Sonnenschein, 4 and Gerrard, 5 and by Moore, 6 who isolated it in its pure state. Thompson, in 1887, 7 obtained from the plant a second amorphous alkaloid, gelseminine, which was found by Cushny 8 to be highly poisonous, 1 mgm. of its hydrochloride being fatal to a rabbit weighing 2850 gm., while gelsemine was inactive to mammals, but produced strychnine-like effects in frogs. Sayre and colleagues 9 showed that gelseminine was not a single substance, but a mixture of 3 alkaloids, to which the names, sempervirine, gelsemidine and gelsemoidine were given; sempervirine being crystalline and the other 2 amorphous, but none of them were as potent as gelseminine itself. In reinvestigating this important drug of American origin, the writer 10 isolated 2 crystalline alkaloids, gelsemine and a new alkaloid, gelsemicine, which has a formula C₂₀H₂₅O₄N₂, a melting point 171°C. and a specific rotation —140°. Gelsemicine is highly potent and produces the usual toxic effects in mammals. A 0.1% solution of its hydrochloride dilates the pupil of rabbits for more than 4 hours. M.L.D. of gelsemicine hydrochloride was recently found by Hou 11 to be 0.05 mg. per kilo. A third crystalline alkaloid, to which the writer gives the name sempervine has now been isolated from the rhizome and root of gelsemium. It is very similar to Sayre's sempervirine in its general chemical behavior but differs from the latter in its melting point.