Pharmacological effect and toxicity of alkaloids from Gelsemium elegans Benth.

Gelsemium elegans Benth. (Loganiaceae), a toxic plant indigenous to southeastern Asia, is well known among hilltribes as an effective means for committing suicide. A crude alkaloidal fraction from its leaves was isolated by conventional acid-base extraction. Tests in animals showed that the alkaloids exerted analgesic and anti-inflammatory effects. At a lethal dose, the alkaloids produced violent clonic convulsions that led to respiratory failure. Since the convulsions could be prevented by pentobarbital or diazepam and potentiated by reserpine, it is postulated that the alkaloids act centrally against GABA action.