TROPANE ALKALOIDS

Lec. ( 3 )

TROPANE ALKALOIDS

Tropane is a dicyclic compound forme by the condensation of a pyrrolidine precursor( ornithine) with three acetate_derived carbon atoms..Both pyrrolidine and piperidine ring systems can be discerned in the molecule .
The important drugs and alkaloids in this group are belladonna leaf, Hyoscyamus, stramonium , atropine , hyoscyamine , scopolamine , coca , and cocaine .

Belladonna

Belladonna leaf. belladonna herb, or deadly nightshade leaf consists of the dried leaf and flowering or fruiting top of Atropa belladonna L.
The poisonous character of the plant has been known for many years, it has a mydriatic and analgesic properties , the leaves were used earlier than the root , the leaf yields alkaloids in conc. Ranging up to more than (1%) , about ¾ of the isolated alkaloid mix. Is Hyoscyamine ; the reminder is atropine . Atropine found in the root but not in the leaf. These include apoatropine, belladonnine, cuscohygrine, and scopolamine .
Belladonna acts as an antimuscarinic agent. which accounts for its use as a spasmolytic drug. It is used as adjunctive therapy in the treatrnent of peptic ulcer; functional digestive disorders, including spastic, mucous, and ulcerative colitis; and diarrhea, diverticulitis, and pancreatitis. It possesses anticholinergic properties and is used to control excess motor activity of the gastrointestinal tract and spasm of the urinary ract.
Belladonna leaf is commonly administered in the form of the tincture ( 30 mg alkaloids / 100 ml ) or the extract (1.25g alkaloids/100g ) .

Solanaceous Alkaloids

The principal alkaloids of this group are hyoscyamine , atropine and scopolamine(hyoscine).These are tropine derivatives and esters and may be prepared synthetically but are usually obtained by extraction from plants of the Solanaceae.These include Atropa beliadonna, Datura strantonium,
Hyoscyamus niger , and Hyoscyamus muticus , another important source is the dried leaves of Dubois a plants of Australia .Atropine and scopolamine have clinically useful effects as antispasmodic which used principality to relieve spasms of the bowel in the treatment of Spastic colitis, gastroenteritis, and peptic ulcer ; an anti secretary effect used to reduce respiratory secretions in anesthesia , gastric secretions in peptic ulcer therapy, and nasal and sinus secretions in common cold and allergy medications ; and a mydriatic and cycloplegic effect used to prevent adhesions between the iris and lens of the eye in cases of iritic.
Atropine is an antidote in cases of poisoning caused by cholinesterase inhibitors such as physostigmine and organophosphate insecticides.
Scopolamine has a depressant activity on the central nervous system end is used to treat motion sickness. I t is also employed for pre anesthetic sedation and for obstetric amnesia in conjunction with analgesics ,and to calm delirium.
Toxicity symptoms that can occur during the therapeutic use of atropine. Scopolamine and belladonna tincture are skin rashes skin flushing, mouth dryness, difficulty in urination, eye pain, blurred vision . and light sensitivity. The patient should also be advised that such anti acids as a mina gels may interfere with absorption of these drugs when taken simultaneously.
Hyoscyamine sulfate is extremely poisonous its an anti cholinergic. It
is used to aid in the control of gastric secretion. Visceral spasm. hyper motility in spastic colitis, and associated abdominal cramps.
in parkinsonism it is used to reduce rigidity and tremors and to control associated sialorrhea and hyperhidrosis.
Atropine sulfate is an antichoiinergic.Used in surgery as an anti sialogogue to control bronchial, nasal, pharyngeal and salivary secretions, it is usually injected intramuscularly prior to induction of anesthesia During surgery, the drug is given intravenously when reduction in pulse range and cessation of cardiac action are attributable to increased vigil activity. It is also useful
in pylorospasm and other spastic conditions of the gastrointestinal tract and for urethral and biliary colic when administered concomitantly with morphine.
Scopolamine or hyoscine is an alkaloid that is particularly abundant in Datura fastuosa var.alba and in D. metel. It is an ester that, upon hydrolysis, yields tropic acid and scopoline,a base resembling atropine.
At usual therapeutic doses, scopolamine is a central nervous depressant whereas atropine is a stimulant. For this reason, scopolamine hydrobromide is used for pre anesthetic sedation and for obstetric amnesia in conjunction with analgesics ; it is also employed for calming delirium. It is administered subcutaneously or intramuscularly in a single dose. In addition to its systemic anti cholinergic effects, scopolamine is effective in the prevention of nausea and vomiting associated with motion sickness.

Hyoscyamus
Hyoscyamus or henbane is the dried leaf, with or without the stem and flowering or fruiting top, of Hyoscyamus niger L. (Fam. Solanaceae) and contains not less than 0.04% of the alkafoids of hyoscyamus.
The alkaloids hyoscyamine and scopolamine,0.05 to 0.I5% of which 3/4 is hyoscyamine, are the active principles.

Stramonium
Strarnonium, jimson weed, or Jamestown
weedc onsists of the dried leaf and flowering or fruiting tops with branches of Datura stramonium L . or of its variety tatula (Linne.) , (Fam. Solanaceac) It yields not less than 0.25% of alkaloids .
Stramonium seed is the ripe seed of Datura stramonium . The ripening capsules are gathered and dried until the seeds shak out .
Stramonium seed contains about 0.4% of alkaloids, principally
hyoscyamine with a small proportion of scopolamine and traces of atropine.
Stramonium is generally regarded as a noxious weed and has frequently caused poisoning in children when seeds were ingested . The chief toxic symptoms are those of atropine poisoning .

Professor Dr. Saad Ali Ihsan
Ph.D. In Medicinal & Aromatic Plants