Physostigmine, Eserine

Physostigmine (Eserine), CijHjjOjNa. The alkaloid is best prepared in the laboratory by Salway s process. Methods of manufaetiu e are described by Chemnitius and by Sehwyzer. ... 

Physostigmine (eserine) is a carbamate found in the calabar bean (Physostigma benenosum), which acts as an anticholinesterase. It was used in West Africa in witchcraft trials by ordeal. It has also been used in human medicine. Insecticidal carbamates are structurally related to it and also act as anticholinesterases (Ballantyne and Marrs 1992). 

Julian, P.L. PM, J. (1935) Studies in the Indole Series. V. The Complete Synthesis of Physostigmine (Eserine). Journal of the American Chemical Society, 57, 755-757. 

Physostigmine (eserine sulfate) causes miosis and spasm of accommodation it also lowers intraocular pressure and hence can be used in the treatment of wide-angle glaucoma. As it is lipid soluble, it penetrates into the brain rapidly, raises the acetylcholine concentration and, in toxic amounts, may cause cholinergic CNS toxicity, which is characterized by restlessness, insomnia, tremors, confusion, ataxia, convulsions, respiratory depression, and circulatory collapse. These effects are reversed by atropine. 

Neurotransmitter inactivation. A number of animal and plant agents act as ANTICHOLINESTERASES, so interfering with synaptic trasmission. These include fasciculins (Fasl, Fas2, FasS), which are peptide snake venoms, huperzine from a plant, onchidal from molluscs and physostigmine (eserine) from the calabar bean. 

Perhaps the most famous instance of enzyme inhibition explaining a gross effect of an alkaloid is the inhibition of cholinesterase by (-)-physostigmine (eserine). Since acetylcholine is such a widespread and essential neurotransmitter, an increase in its concentration at synapses has serious consequences and physostigmine by inhibiting the hydrolysis intensifies and prolongs the action of acetylcholine on its receptors [372]. 

Physostigmine (eserine) 0.25% ointment Glaucoma, accommodative esotropia, louse and mite infestation of lashes Retinal detachment, miosis, cataract, pupillary block glaucoma, iris cysts, brow ache, punctal stenosis of the nasolacrimal system... 

The identification of acetylcholine as the chemical mediator in postganglionic parasympathetic transmission [2] and the subsequent demonstration of the natural occurrence of a cholinesterase led to the observation of the inhibition of this enzyme by physostigmine (eserine) [3]. Cholinesterases were identified later in horse serum and their actions studied using various substrates [4]. Studies of the distribution of acetylcholine and of cholinesterases have shown that they occur at four principal sites in the mammalian body [5-8] ... 

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