Colocynth

COLOCYNTH (bitter apple, Fructus Colocynthidis, s. Colocynthis, s. Poma Colocynthidis), the fruit of the annual plant Citrullus Colocynthis (Schrader), s. Cucumis Colocynthis (L.), family Cucurbitaceae, growing wild and partly cultivated in Asia Minor, North Africa, Spain, etc. The fruit of the colocynth is the size of an orange, covered with a smooth, thin, light-yellowish skin, which is removed from the fruits before drying. The pulp of the fruit contains a large number of seeds, similar to cucumber seeds. The fruit has an unpleasant, nauseating odor and a sharp, bitter taste; it is highly poisonous. Its seeds are pharmacologically inactive and are removed during the preparation of the pharmaceutical product. The active principle of the colocynth is considered to be the glycoside colocynthin, C₅₆H₈₄O₂₃ (Walz), a loose, yellowish powder, soluble in water, less so in alcohol, with a strongly bitter taste. According to Walz, colocynthin is split by acids into glucose and colocynthidin. Furthermore, a resin-like citrullin, which acts similarly to colocynthin, has been isolated from the colocynth. According to other studies, the active principles of the colocynth are not a glycoside, but an alkaloid-like substance, which in dogs, even in a dose of 0.1 g, causes the laxative effect characteristic of the colocynth. Thus, the active principles of the colocynth have not yet been sufficiently studied chemically. Colocynth powder strongly irritates mucous membranes and, when introduced into subcutaneous tissue, causes inflammation; 5-30 mg of so-called colocynthin or 100-300 mg of colocynth causes liquid stools in humans after several hours, accompanied by tenesmus and pain, and with large doses (0.6-1.0 g of colocynth), vomiting, severe pain, and very frequent stools mixed with blood occur. Fluoroscopic studies on animals have shown that the colocynth causes sharp excitation of the peristalsis of the small intestine, the loss of antiperistaltic movements of the large intestine, strong secretion of mucus, and transudation into the intestinal cavity. With an increase in doses, acute hemorrhagic gastroenterocolitis occurs. The administration of opium prevents diarrhea by delaying the passage of the colocynth from the stomach into the intestine; however, this facilitates the absorption of the colocynth from the stomach, which can lead to the death of the animal. The resorptive effect of the colocynth is characterized by irritation of the kidneys (hemorrhagic glomerulonephritis), and large doses cause symptoms of collapse (the minimum lethal dose for humans is 4 g per os). The colocynth is used as a purgative laxative (drasticum), and like all substances of this group, it is used in practice relatively rarely. The average dose of the colocynth is 0.1; the maximum single dose is 0.3; the maximum daily dose is 1.0. It is used in the form of powders and pills, for which a dry extract of the colocynth is used. A tincture is also used: the average dose is 0.25-0.5; the maximum single dose is 1.0; the maximum daily dose is 3.0. The colocynth is part of some complex laxatives, for example, Pilulae laxantes fortes; a single dose of them contains 0.005-0.01 of the colocynth.