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Thursday, March 19, 2009

HOW TO CLASSIFY ALKALOIDS?

“Classification”

Various schemes have been suggested for the classification of alkaloids.

The following plan is based on the ring structure or nucleus of the chief alkaloidal group in the combined group.

Pyridine-piperidine combined group.

Examples: Nicotine, Lobeline, and Arecoline.

Tropane alkaloids:

Examples: Atropine, Hyoscyamine, and Hyoscine.

Quinoline alkaloids.

Examples: Quinine, Quinidine, Cinchonine, and Chinchonidine.

Isoquinoline alkaloids:

Examples: Emetine, cephaeline, Hydrastine, Morphine, Codeine.

Indole alkaloids.

Examples: Reserpine, Vinblastine, Vincristine, Strychnine, Brucine, Physostigmine, Ergotamine, and Ergonovine.

Imidazole alkaloids :

Examples: Pilocarpine, isopilocarpine.

Steroidal alkaloids:

Examples: Veratridine, Veratrosine, and Vratromine.

Alkaloidal amines:

Examples: Ephedrine, Colchicine.

Purine bases:

Examples: Caffeine, Theophylline, and Theobromine.

A. Pyridine-Piperidine group:

“Areca Nut”

B.O Areca catechu

Family Palmae.

P.U Dried ripe seed.

Commerce and production

The seeds are removed from the fruits, boiled in water containing lime and dried. Seeds are usually 2.5 cm in length and rounded, conical in shape. The seed is very hard, has a faint odour, when broken.

It has an astringent and acid taste.

Constituents:

Arecoline, Arecaidine, Guvacine, Guvacoline.

Uses:

Anthelmintic, in veterinary medicine.

It is employed as Vermicide, and taenifuge.

(Vermicide is an agent that kills intestinal worms.)

(Taenifuge is an agent that expels tapeworm)




“Lobelia

B.O Lobelia inflata

Family Lobeliaceae.

P.U Dried leaves and flowering tops.

Collection:

It is collected after a portion of capsule is inflated. Dried carefully and preserved for shipment.

Constituents:

Drug contains fourteen alkaloids of which Lobeline is major and the most important.

Uses:

Used in galenical preparations as an expectorant. It is reported that Lobeline is respiratory stimulant. It is used as smoking deterrent (hindering).





“Nicotine”

B.O Nicotiana tabacum

Family Solanaceae

P.U Dried leaves.


Constituents:

Nicotine, Nor-nicotine, Campharine etc.

Uses:

Nicotine chewing gum intended for cigarette smokers seeking to give up smoking.






B. Tropane alkaloids:

“Belladonna”

B.O Atropa belladonna.

Family Solanaceae.

P.U dried leaves and roots.

Constituents

Hyoscyamine

Atropine.

Pyridine etc.

Uses:

Parasympathetic depressant. As adjunctive therapy in treatment of peptic ulcer and digestive disorders. In amanita mushroom poisoning. In poisoning due to organoposphates. In heavy metal poisoning, etc.





“Hyoscyamus”

B.O Hyoscyamus niger

Family Solanaceae

P.U Dried leaves and flowering and fruiting tops.

Constituent:

Hyoscyamine, Scopolamine

Uses:

Parasympatholytic.





“Starmonium”

B.O Datura stramonium.

Family Solanaceae.

P.U Dried leaves and flowering tops.

Constituents:

Hyoscyamine and scopolamine.

Uses:

Ø Anticholinergic.

Ø Vapours are used for asthma.

Ø Ingredient in preparations intended for burns.


(C.)Quinoline alkaloids:

“Cinchona”

B.O………… Cinchona succirubra.

Cinchona calisaya

Cinchona officinalis.

Cinchona ledgeriana

Family………. Rubiaceae.

P.U ………….. Dried bark of stem or of root.

Collection:

The fresh bark of both trunk and root are removed by hands and cut into small pieces which are dried carefully and into bags for export.

Constituents:

It is reported that about 25 alkaloids are present in cinchona. The most important of which are quinine, Quinidine, Cinchonine, and cinchonidine.

Uses:

Anti malarial,

Anti pyretic,

Bitter tonic and

In cardiac arrhythmia.

(D). Isoquinoline alkaloids:

“Ipecac”

B.O………… Cephaelis ipecacuanha

Family……. Rubiaceae.

P.U………… dried root and rhizomes

Constituents:

Emetine, cephaeline, psychotrine.

Uses:

Emetic, Expectorant, stimulant, and in certain drug overdose.

“Hydrastis”

B.O……… Hydrastis canadensis

Family…… Ranunculaceae

P.U……….. Dried roots and rhizome.

Constituents:

Hydrastine, Berberine, canadine.

Uses:

Astringent in inflammations of mucous membrane.

“Opium”

B.O………. Papaver somniferum

Family……. Papaveraceae

P.U………… Air-dried milky exudate from ripened poppy capsule.

Cultivation:

The cultivation of the opium poppy is controlled internationally by the “International Narcotic Control Board of United Nations”.

The poppy seed are sown in winters in well cultivated soil. In the spring , when the plant attain a height of 15cm, the fields are cultivated, and plants are thinned to stand about 60cm apart. The poppy blossoms in April to May and the capsules mature in May or June. Each plant bears 5-8 capsules.


Collection:

The ripened capsules, about 4cm in diameter , change from blush green to yellowish in colour. This time is critical for the collection of latex. The capsules are incised with a knife, which is usually three bladed and the incision is made around the circumference of the endocarp is broken. The latex flows into the interior of the capsule and is lost. The latex, which is at first white, rapidly coagulates and turns brown to blackish in colour. It is collected the very next morning with the help of scraper and then wrapped in the poppy leaves and dried in the shade. Finally they are packed in bags for shipment.


Constituents:

It contains about 25 alkaloids out of which important are as follows.

Morphine…………………….. 4-12%

Codeine………………………. 0.8-2.5%

Noscapine……………………. 4-8%

Papaverine…………………… 0.5-2.5%

Thebaine……………………… 0.5-2%


Uses

It acts chiefly on the CNS; it first stimulates and then depresses nerve response.

Analgesic,

Hypnotic,

Narcotic,

For constipation,

Anti tussive,

Contracts the eye pupil.



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