Anticholinesterase alkaloid

The anticholinesterase alkaloid physostigmine (250) was photodegraded at 300 nm to deoxyeseroline (251) in 10% yield, along with a not readily purified... 

Another fruitful means of identifying pharmacologically active natural products has been that of folk law remedies, many of which are plant products. Typical examples include alkaloids, such as atropine (from plants of the Solanaceae family, known to the ancient Greeks) and reserpine (from Rauwolfia serpentina, the snakeroot), which is popular in India as a herbal remedy for use as a tranquilizer or antihypertensive. Other chapters in the book relate to stigmines (based on phy-sostigmine, an anticholinesterase alkaloid from the Calabar bean in West Africa) that are used to treat Alzheimer s disease (Chapter 11-12), and opioid receptor ligands (based on morphine, the most important alkaloid of the opium poppy) for pain relief and as antitussives (Chapter 11-11). 

Huperzine A, a potent anticholinesterase alkaloid, and huperzine B were separated from a Chinese medicinal herb, Huperzia serrata (Thunb) Trev. Lycopodium serratum Thunb.), (Lycopodiaceae), by Liu et al [25]. The plant was used in Zhejiang Province of China for treatment of some mental disorders. 

Chaiyana W, Rades T, and Okonogi S. (2013). Characterization and in vitro permeation study of microemulsions and liquid crystalline systems containing the anticholinesterase alkaloidal extract from Tabernaemontana divaricata. International Journal of Pharmaceuticals, 452, 201-210. 

Atropine and its analog scopolamine are two of the most important antimnscarinic drugs. These alkaloids and the compounds derived from them are used in ophthalmology and anesthesiology, in cardiac and gastrointestinal illnesses, and in Parkinsonism. It also is very important as an antidote during anticholinesterase intoxication. 

Eserine (physostigmine) has a pyrroloindole skeleton. This alkaloid is used as an anticholinesterase drug, which is fairly important in the treatment of Alzheimer s disease. Eserine is synthesized in Physostigma venenosum and stored in the seeds of this leguminous plant. The synthesis pathway starts with tryptamine, which is transformed into eserine (Eigure 45). 

The pharmacological properties of P-erythroidine and its dihydro derivative are very similar to those of d-tubocurarine and therefore need not be described in any detail. The two compounds differ from curare in three important respects, namely, less potent paralytic action on neuromuscular junctions, briefer duration of paralysis, and oral efficacy. Indeed, gastrointestinal absorption of the alkaloids is so rapid and complete that the difference between effective oral and subcutaneous doses is rather small. Dihydro-P-erythroidine is longer acting than P-erythroidine and about six times as active. Similar to curare, P-erythroidine and its dihydro derivative are antagonized at the neuromyal junction by anticholinesterases such as neostigmine. 

Galantamine, unlike the other anticholinesterases in clinical use, is derived from the alkaloids from the daffodil and snowdrop family. It is a reversible, competitive inhibitor of acetylcholinesterase with some inhibitory action on butyryl cholinesterase. It is also an agonist at nicotinic receptor sites. Although a clinically effective drug, galantamine frequently causes gastrointestinal side effects. 

A central African term for a substance prepared from the cortex of the roots of Taber-nanthe iboga. Large doses are said to produce catalepsy and death. Main active component is ibogaine and twelve other alkaloids. Psychological effects like those of tricyclic antidepressants, plus monoamine oxidase inhibitors and anticholinesterases. 

Physostigmine (also called eserine) is an alkaloid obtained from the leguminous plant Calabar or ordeal bean—the dried, ripe seed of Physostigma Venenosum Balfour, a perennial plant in tropical West Africa. The main alkaloid was first isolated from the seeds of the Calabar bean in a pure form in 1864 by Jobs and Hesse, who called it physostigmine. One year later, it was obtained in a crystalline form by Vee and LeVen, who called it eserine. Physostigmine (PHY) is the first anticholinesterase agent known to man and is used in the treatment of atropine-induced intoxication. 

Two well-known alkaloids, cocaine (3.11) and atropine (3.12), are ester derivatives of the 8-azabicyclo[3.2.1]octane ring system. Cocaine, isolated from a variety of the poppy plant, has been used as a topical anesthetic, but it is highly addictive if it enters the bloodstream and is now a controlled substance. Atropine, however, is highly useful in medicine with anticholinergic properties. It is isolated from the Belladonna plant and has been used for many years to dilate the pupil of the eye. It is also an effective antidote to poisoning by anticholinesterase chemicals, when these are used as insecticides or in extremely toxic form as chemical warfare agents. 

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