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ALKALOIDS, ALKALOIDS, DISTRIBUTION AND DISTRIBUTION AND

ANALYSISANALYSIS

Seat no.: 1050

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INTRODUCTIONINTRODUCTION

• Group of naturally occurring organic substances having a cyclic nitrogenous nucleus.

• Physiologically active

• Widely used to treat diseases from malaria to cancer.

• Extremely poisonous in high doses while in small doses it has many therapeutic uses.

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GENERALGENERAL CHARACTERISTICSCHARACTERISTICS

• Bitter to taste

• Most are crystalline solids except a few are amorphous and some are liquid.

• Insoluble in water

• Sharp melting point

• Colour

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CHEMICALCHEMICAL PROPERTIESPROPERTIES

• Nitrogenous bases with tertiary amines

• Alkaline pH

• Contain one or more rings of carbon atoms, usually with a nitrogen atom in the ring

• Position of the nitrogen atom effects the property of alkaloids

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FUNCTIONFUNCTION OFOF ALKALOIDS ALKALOIDS IN PLANTSIN PLANTS

• Protection against insects and animals

• Final products of detoxification

• Source of nitrogen

• Growth regulators

• Source of energy

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BIOSYNTHESISBIOSYNTHESIS ININ PLANTSPLANTS

• Formed from amino acids

• Alkaloidal precursors: phenylalanine, tyrosine, tryptophan, histidine, anthranilic acid, lysine and ornithine.

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DISTRIBUTIONDISTRIBUTION OFOF ALKALOIDSALKALOIDS ININ PLANTSPLANTS

• Alkaloids are distributed mostly in the following angiosperms:APOCYNACEAEPAPAVERACEAERANUNCULACEAERUBIACEAESOLANACEAE ANDBERBERIDACEAE

• Alkaloid production from monocotyledon – Amaryllidaceae and Liliaceace

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DISTRIBUTIONDISTRIBUTION OFOF ALKALOIDSALKALOIDS ININ PLANTSPLANTS

• All Parts e.g. Datura.

• Barks e.g. Cinchona

• Seeds e.g. Nux vomica

• Roots e.g. Aconite

• Fruits e.g. Black pepper

• Leaves e.g. Tobacco

• Latex e.g. Opium

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NOMENCLATURENOMENCLATURE

• The names of alkaloids are obtained in various ways:

• From the specific name of the plant yielding them. E.g.:- such as Cocaine from Erythroxylon coca

• From the common name of the drug they yield . E.g.:- ergotamine

• From the generic name of the plant yielding them E.g.:- nicotine from Nicotiana tabacum

• From their physiological activity. E.g.:- morphine.

• Occasionally from the discoverer. Eg:- pelletierine

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BASICBASIC NUCLEUSNUCLEUS OFOF ALKALOIDSALKALOIDS

NH NH N

N NH

N-CH3

NN

N-CH3

N

NH

N

N

N N

HN

N

HN

Pyrrole Pyrrolidine Pyrrolizidine Pyridine Piperidine Tropane

IsoquinolineQuinoline Aporphine Nor-lupinane

Indole Indolizidine Imidazole Purine

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CLASSIFICATIONCLASSIFICATION OF OF ALKALOIDSALKALOIDS

• They are broadly classified into:

Proto alkaloids e.g.: ephedrine

Pseudo alkaloids e.g.: caffeine

True or heterocyclic alkaloids e.g.: nicotine

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• Classification based on the ring structure or nucleus of the chief alkaloid group in the plant drug:

– Pyridine and piperidine eg: nicotine from Nicotiana tobacum

– Tropane :- solanaceous alkaloids – Hyoscine from Datura fastuosa and coca alkaloids – cocaine from coca leaves

– Quinoline :- cinchonine from cinchona bark

– Isoquinoline :- morphine from Papaver somniferum

– Indole :- vinblastine and vincristine from Catharanthus roseus

– Imidazole:- pilocarpine from pilocarpus

– Steroidal :- germicides, veratridine from Veratrum viride

– Alkaloidal amines :- ephedrine from Ephedra sinica

– Purine bases :- caffeine from Coca nitida

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NICOTINENICOTINE

• Found in the nightshade family of plants

• Hygroscopic, oily liquid

• It has a pyridine ring with pyrrole side chain

POSITIVE NEGATIVE

Anxiolysis

Cognitive Enhancement

Cerebro-vasodilation

Neuroprotection

Analgesia

Anti-psychotic

Gastrointestinal Distress

Hypothermia

Emesis

Hypertension

Seizures

Respiratory Distress

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PHARMACOLOGICAL PHARMACOLOGICAL ACTIVITYACTIVITY ANDAND USESUSES

ALAKALOID MEDICINAL USES

Vinblastine, vincristine antitumor

Codeine cough medicine, analgesic

Cocaine anesthetic Morphine analgesic

Quinidine antiarrhythmic

Quinine antipyretics, antimalarial

Ergot alkaloids vasodilator, antihypertensive

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GENERALGENERAL TESTTEST PROCEDURES PROCEDURES FORFOR ALKALOIDALKALOID ANALYSISANALYSIS

• All alkaloids in acid solution give precipitates with heavy-metal reagents such as Mayer’s and Dragendroff’s.

• Insoluble in water, soluble in alcohol and other organic solvents

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ALKALOIDALALKALOIDAL REAGENTSREAGENTS

• MAYER’S REAGENT: gives a cream precipitate

• DRAGENDROFF’S REAGENT: gives a reddish brown precipitate

• WAGNER’S REAGENT: produces reddish brown precipitate

• PICRIC ACID SOLUTION: gives a yellow precipitate.

• 10% TANNIC ACID SOLUTION: gives a buff colored precipitate

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QUANTITATIVE QUANTITATIVE DETERMINATION OF DETERMINATION OF

ALKALOIDSALKALOIDSPROCESS OF EXTRACTION

LIBERATING FREE BASE BY MEANS OF A SUITABLE ALKALI

EXTRACTION OF ALKALOID WITH ORGANIC SOLVENT LIKE CHLOROFORM

ADD DILUTE ACID AND SHAKE, ALKALOID FORM SOLUBLE SALTS AND PASS INTO SOLUTION IN THE AQUEOUS LAYER

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LIBERATE FREE BASES BY ADDITION OF AKALI

EXTRACT ALKALOID BY MEANS OF AN IMMISCIBLE ORGANIC SOLVENT.

EVAPORATE ON WATER BATH, DRY IN OVEN AND WEIGH

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QUALITATIVE ANALYSIS OF QUALITATIVE ANALYSIS OF ALKALOIDSALKALOIDS

• TLC

• HPTLC

• HPLC

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ANALYSISANALYSIS OFOF ALKALOIDSALKALOIDS BYBY TLCTLC

• For the identification of drugs containing known alkaloids pharmacopoeias commonly employ TLC separations using reference compounds to establish the presence of individual alkaloids.

• Developing reagent used- Dragendroff’s reagent.

• Stationary Phase - Silica gel 60F 254

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DIFFERENTDIFFERENT SOLVENTSOLVENT SYSTEMSSYSTEMSSolvent systems Alkaloid

Toluene-ethyl acetate-diethylamine(70:20:10) (v/v)

For majority of alkaloids

Chloroform-diethyl amine (90:10) (v/v) cinchona alkaloids i.e. quinine, quinidine.

Toluene-acetone-ethanol-conc.ammonia(40:40:6:2) (v/v)

Opium alkaloids like morphine, odine

Acetone-water-conc.ammonia(90:7:3) (v/v) Atropine, hyoscyamine and solanaceaeous alklaoids

Ethyl acetate-methanol-water(100:13.5:10) (v/v)

Rauwolfia alkaloids; xanthine derivatives like caffeine etc.

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DIFFERENTDIFFERENT SOLVENTSOLVENT SYSTEMSSYSTEMSSolvent systems Alkaloid

Toluene-chloroform-ethanol (28.5:57:14.5 v/v)

Secale alkaloids

N-heptane-ethylmethyl ketone-methanol (58:34:8 v/v )

Rauwolfia alkaloids

Toluene-methanol (86:14 v/v ) Colchici semen

n-propanol-formic acid-water (90:1:9 v/v ) Beberidis cortex

Hydrastis rhizoma

Colombo radix

Cyclohexane-chloroform-glacial acetic acid (45:45:10 v/v )

Berberine, and protoberberine type alkaloids

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IDENTIFICATIONIDENTIFICATION OFOF NICOTINE NICOTINE FROMFROM LeucasLeucas asperaaspera

• commonly called chota halkusa.

• used as an insecticide

• indicated in traditional medicine for coughs, colds, painful swellings and chronic skin eruptions.

• antipyretic

• wound healing property and is used in cobra venom poisoning

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HPTLCHPTLC of of Leucas asperaLeucas aspera

• Solvent system - toluene: ethyl acetate: diethyl amine (70:20:10 v/v)• TLC Chromatogram of LAA at 540 nm.

• Peak at Rf =0.66

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HPTLCHPTLC of of Leucas asperaLeucas aspera

• Solvent system - toluene: ethyl acetate: diethyl amine (70:20:10 v/v)

• TLC Chromatogram of nicotine at 540 nm.

• Peak at Rf =0.65

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HPLC OF Leucas asperaHPLC OF Leucas aspera• HPLC of nicotine standard, RT =

2.45 min

• HPLC of Leucas aspera RT = 2.44 min

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REFERENCESREFERENCES

• Pulok K Mukherjee:Quality Control of Herbal Drugs , volume I , 2008, Business horizon, 8190078844

• Isolation and Identification of Nicotine from Leucas aspera (Wild)- Journal: Indian Journal of Pharmaceutical Sciences, Year : 2006 | Volume : 68 | Issue : 1 | Page : 88-90 Copyright: Indian Pharmaceutical Association

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