Also found in: Dictionary, Thesaurus, Medical, Wikipedia.


(organic chemistry)
C15H21O2N3 An alkaloid; poisonous, colorless-to-pinkish crystals; soluble in alcohol and dilute acids; melts at 86°C; used as a source of salicylate and sulfate forms. Also known as calabarine; eserine.



(also eserine), C15H21O2N3, the chief alkaloid of Calabar beans, which are the seeds of the tropical African woody vine Physostigma venenosum. Physostigmine was discovered in 1864 by the German chemists Jobst and Hesse; the first synthesis of the alkaloid was carried out in 1935 by the American chemists P. Julian and J. Pikl. A weak base, the alkaloid yields salts that readily crystallize. It is soluble in alcohol, ether, and chloroform. The structural formula is

Physostigmine is highly poisonous. It is used in medicine, where it is classified as a reversible anticholinesterase. When administered medically, physostigmine blocks the enzyme cholinesterase, thereby protecting acetylcholine from a rapid hydrolytic breakdown. Physostigmine thus induces effects in the organism that are outwardly similar to those induced by acetylcholine and cholinomimetic agents (contraction of the pupils, slowed heartbeat, intensification of uterine contractions and of peristalsis in the stomach and intestine).

The protection of acetylcholine effected by physostigmine has made possible the discovery that acetylcholine is given off at the endings of the parasympathetic nerves and that nerve impulses are transmitted chemically. Physostigmine salicylate is used medically as an anticholinesterase. It is used mainly in ophthalmology, where in drop form it serves to contract the pupils and to reduce the intraocular pressure arising from glaucoma; in ointment form, it is effective against keratitis. Hypodermic injections of physostigmine are sometimes prescribed for neuromuscular diseases (myasthenia), enteroparesis, and paresis of the urinary bladder. Physostigmine is an antidote for atropine and curarine. Synthetic substitutes for physostigmine, for example, neostigmine, are available.


References in periodicals archive ?
The best known natural inhibitor of AChE is pyrroloindole alkaloid physostigmine isolated from Physostigma venenosum.
Use of physostigmine for hallucinogenic plant poisoning in a teenager: case report and review of the literature.
Sedation with benzodiazepines is often indicated later; and physostigmine, 1-2 mg intravenously and repeated as indicated every 30-60 minutes (to a maximum total dose of 5-6 mg), can reverse a central anti-cholinergic syndrome in severe cases with coma and tachydysrhythmias.
Physostigmine was considered but because of the self-limiting and good clinical course it was not administered.
The substances - scopolamine and physostigmine - act on acetylcholine receptors.
Effects of scopolamine, physostigmine and chlordiazepoxide on punished and extinguished water consumption in rats.
Also, TDE effects were similar to those of galanthamine, as demonstrated in this study, and those of physostigmine in a previous study.
Treatment with physostigmine is indicated only in severe cases to reverse anticholinergic toxicity (1).
Physostigmine is a reversible cholinesterase inhibitor used to reverse the central effects of anticholinergic overdose.
Physostigmine effects on serotonin uptake in human blood platelets.
Oleic acid (3%) was successful in enhancing the flux of the tetrapeptide melanotropin-hisetal across hairless mouse skin and human skin, but enhancement across human skin was much less (25,26) and oleic acid (50:50) produced greater transdermal delivery of physostigmine than propionic acid alone (27).
Julian's patents was for his process for synthesizing physostigmine for the treatment of glaucoma.