Alkaloids

Definition• Alkaloids may be defined as basic nitrogenous

compounds which occur abundantly in the plant kingdom. They contain one or more nitrogen usually in a heterocyclic ring and have a marked physiological action on man & animals.

• The nitrogen may exist as primary (1° amines), secondary (2° amines) or tertiary (3° amines) amine.

• These compounds are basic but the degree of their basicity depends on the structure of the molecule and presence and location of other functional groups.

Examples:

N

N

CH3

Nicotine

N CH3 O C

O

CH

CH2OH

Atropine

Functions of Alkaloids in plants

The possible functions of alkaloids in plants are:• They are poisonous agents that protect the plants

against insect & herbivores.• Alkaloids are reserve substances capable of

supplying nitrogen or other necessary elements to the plant.

• They may regulate growth/work as growth regulatory factor.

• They are end product of detoxification reactions representing a metabolic locking-up of compounds otherwise harmful to the plant.

Properties• Most alkaloids are well defined crystalline solids and

they unite with acids to form salts. In the plants they may exist in the Free State or as alkaline salts.

• The alkaloids are usually insoluble or sparingly soluble in water but their salts with acids are freely soluble in water.

• The free alkaloids are soluble in Ether, Chloroform or other non-polar solvents in which the salts are insoluble. This property now permits a ready mean for the isolation and purification of alkaloids.

• The alkaloids usually possess a bitter taste.

Pharmacological actions:

Pharmacological action Example

1 Analgesic & narcotic Morphine, Codeine

2 CNS stimulant Strychnine3 Mydriatic Atropine4 Miotic/Glaucoma Pilocarpine5 Hypertensive Ephedrine6 Antihypertensive Reserpine7 Antineoplastic/anti cancer Vinblastine, Vincristine8 Emetic Emetine, Sanguinarine9 Cardiac

arrhythmia/dysrhythmiaQuinidine

10 Skeletal muscle relaxant (+)-Tubocurarine11 Oxitocic Ergonovine (also known as

Ergometrine) and it’s derivatives

The alkaloids have a wide range of pharmacological actions:

Test for Alkaloids

Reagents Color

Mayer’s reagent (Potassium mercuric iodide solution) Cream

Wagner’s reagent (solution of I₂ in KI) Reddish brown

Dragendorff’s reagent (solution of potassium bismuth iodide) Reddish brown

Hager’s reagent (saturated solution of picric acid) Yellow

Most alkaloids are precipitated from neutral or slightly acid solutions by various re-agents. The precipitate may be amorphous or crystalline and are of various colures such as:-

ClassificationAlkaloids may be classified in a number of ways. For example: they may be classified according to source, chemical structure or pharmacological actions etc. Each system has its advantages and disadvantages.Usually they are classified on the basis of the ring structure or nucleus of the alkaloid as follows• Pyridine-Piperidine group• Tropane group• Quinoline group• Isoquinoline group• Indole group• Imidazole group• Steriodal group• Alkaloidal amino group• Lupinane group• Purine group

Pyridine-Piperidine group: • The alkaloids in this group contain Pyridine or

Piperidine in the molecule. The important alkaloids in this group are Nicotine, Coniine, Arecoline, Lobeline etc.

N

Pyridine

NH

Piperidine

Examples:

N

N

CH3

Nicotine

NH

CH2

H2C CH3

Coniine

Areca/areca nut/betel nut

Biological source:Areca is the dried, ripe seed of Areca catechu Linne of Palmae family. The plant is a tall beautiful palm.Constituents:The total alkaloid content is areca can reach 0.45% containing• Arecoline. The most abundant and physiologically most

active alkaloid. It is liquid and may exist upto 0.20% of total content in areca.

• Arecaidine• Guvacine• GuvacolineAreca also contains• Tannins (15%)• Lipid• Volatile oils and gum

N O

O

Arecoline

Use:Anthelmintic in vaterinary practice as vermicide (expel intestinal worms) and taenifuge (expel tapeworms).

Tropane Alkaloids• Tropane is a dicyclic compound where both

Pyrrolidine and Piperidine ring systems are present.

• The important alkaloids in this group are Atropine, Hyoscyamine, Hyoscine (scopolamine) etc.

NH

Pyrrolidine

N CH3

TropaneNH

Piperidine

N CH3 O C

O

CH

CH2OH

Atropine

Example

Biosynthesis of Tropane alkaloids:

• Tropane is formed by the condensation of Pyrrolidine compound with 3 acetate derived carbon atoms.

• The Pyrrolidine ring is formed from amino acid ornithine.

• The remaining 3 carbon atoms are derived from acetate and methylation results in the completion of the tropine nucleus.

• The 3-hydroxy derivative of tropane is called tropine.

• On the other hand from phenylalanine tropic acid is formed via rearrangement and other reactions.

• Esterification of tropine and tropic acid results in the formation of Hyoscyamine and thus other Tropane alkaloids are synthesized.

N CH3

Tropine

OH N CH3

Scopine

OHO

HCHOOC

CH2OH

Tropic Acid

HCHOOC

OH

Mandelic Acid

Biosynthesis of Tropane AlkaloidCOOH

NH2

NH2

Ornithine

N CH3

Tropine

OH

H2C

HCHOOC

NH2

Phenylalanine

HCHOOC

CH2OH

Tropic Acid

N CH3 O CHC

O

CH2OH

Hyoscyamine

N CH3 O CHC

O

CH2OH

O

Scopolamine

Biosynthesis of CocaineCOOH

NH2

NH2

Ornithine

N CH3

Ecgonine

OH

H2C

HCHOOC

NH2

Phenylalanine

N CH3 O C

O

COOH

2CH3COOH + CH3

COOCH3

Cocaine

Belladonna/ deadly nightshade:

Biological source:• Belladonna leaf consists of dried leaf and flowering or fruiting

tops of Atropa belladonna Linne or its variety acuminata of Solanaceae family.

• Belladonna root consists of dried roots of Atropa belladonna LInne of Solanaceae family.

• The plant is a perennial herb that grows to 1m in height. “Atropa” is from greek “atropos” meaning inflexible.

• Atropos is the name of Greek Fate who cuts the thread of life and probably refers to the poisonous character of the drug.

• “Belladonna” is from two Italian words “bella” meaning beautiful and “donna” meaning lady.

• This probably refers to the fact that, juice of the berry of plant when placed in the eyes causes dilation of the pupils giving an outstanding appearance.

Constituents:• Belladonna leaf yields about 0.4% (no less than

0.35%) and belladonna root yields about 0.6% alkaloids containing

• About ¾th of the mixture is Hyoscyamine• Remaining is atropineUse:• As Mydriatics• As parasympatholytic agent (depress or block

parasympathetic nerve). Thus it decreases the flow of most secretions like saliva, sweat, milk, gastric secretion etc. Thus it is used as adjunct therapy in peptic ulcer and different GIT disorders.

Stramonium/thorn apple/jimson weed/Jamestown weed

Biological source: • It consists of dried leaf and flowering or fruiting

tops (with branches) of Datura stramonium Linne or its variety Tatula torrey of Solanaceae family.

• The plant is an annual herb that attains height of about 2m.

Constituents: The drug contains 0.2 -0.4% alkaloids (it yields no less than 0.25% if ideal). The alkaloids present are Tropane alkaloids-• Hyoscyamine. This is more abundant• ScopolamineUse: Its actions are similar to belladonna. It is used as• Parasympatholytic• Anticholinergic• It is used in preparations intended to burn to yield

vapor that relief asthma.

Hyoscyamus/henbane:Biological source: • Hyoscyamus or henbane is the dried leaf with or

without the flowering or fruiting top of Hyoscyamus niger Linne of Solanaceae family.

Constituents: The drug contains about 0.05 – 0.15% alkaloids (no less than 0.04%). Alkaloids include• Hyoscyamine (3/4th)• Scopolamine

Use:• As parasympatholytic but its use is as crude drug

in medicine is rare.• Egyptian henbane (Hyoscyamus muticus) yields

about 1.5% alkaloids most of which is Hyoscyamine

Coca/Coca LeafBiological source:• It is the dried leaves of Erythoxylum coca Lamack

(Huanuco coca) or E. truxillence Rusby (Truxillo coca) of Erythroxylaceae family.

• The plant is a shrub or small tree attaining a height of about 2m.

There are several varieties• Huanuco coca• Truxillense coca• Colombian coca

Constituents:Coca contains three basic types of alkaloids• Derivatives of ecgonine• Derivatives of tropine• Derivatives of hygrine

With different variety the composition of alkaloid mixture varies. But cocaine is the major alkaloid. Cocaine is the methyl ester of benzoyl ecgonine. Where hydrolyzed it splits into ecgonine, benzoic acid and methyl alcohol.• Huanuco coca yields about 0.5-1% of alkaloids whereas

Truxillense coca give lower amount but higher percentage of cocaine.

Use:• Cocaine and its hydrochloride salt are local anesthetic (applied

as 1-4%).• When taken internally it is CNS stimulant.• When taken in larger dose or used continuously it becomes

narcotic.

Quinoline Alkaloids• Alkaloids containing the Quinoline ring as the

principal nucleus are Quinine, Quinidine, Cinchonine, cinchonidine etc.

N

Quinoline

Example:

N

N

CH2

OH3C

HO

Quinine

Biosynthesis of Quinoline alkaloids

• The precursor of quinine and other Quinoline alkaloids is Tryptophan.

• Its biosynthesis in plant is not fully understood but in microorganisms it is obtained via shikimic acid pathway.

• In this pathway, shikimic acid through a series phosphorylation reaction yields chorismic acid.

• Chorismic acid is an important branch point where one branch leads to prephenic acid and then to aromatic amino acids like tyrosine, phenylalanine where the other branch lead to anthralinic acid and then to Tryptophan.

• Tryptophan and corynanthe like monoterpene form corynantheine which yield quinine.

Biosynthesis of tryptophan in

microorganism

HO

OH

OH

COOH

Shikimic acid

PO

OH

OH

COOH

5-Phospho-shikimic acid

NH2

from glutamine

COOH

NH2

NH

CH2CHCOOH

NH2

Anthranilic acid

Tryptophan

NH

CH2CHCOOH

NH2

Tryptophan

+

Corynanthe type monoterpenoid

Corynanthein

Cleavage of benzopyrrole ring and rearrangement

N

N

CH2

OH3C

HO

Quinine

Cinchona/Peruvian bark/ cinchona bark

Biological source:• It is the dried bark of the stem or the roots of

Cinchona succirubra or its hybrids (red cinchona) and C. ledgeriana, C. calisaya or hybrids of these with other Cinchona species (Yellow cinchona) of Rubiaceae family.

• The plant is a tall tree attaining 15-20 m.

Constituents:Cinchona contains about 25 closely related alkaloids. The average yield is 6-7%. The alkaloids include• Quinine• Quinidine• Cinchocine• Cinchonidine

In the red cinchona Cinchonidine exist in greater proportion (as much as 18%) whereas in yellow bark two third is quinine.

Use:• As febrifuge. Cinchona bark and its alkaloids have

been used in the treatment of malaria fever for many years. Quinine is still used in material treatment in many parts of the world.

• Quinidine is cardiac depressant and used to prevent auricular (atrial) fibrillation to coordinate contraction of the auricular (atrial) muscle.

Cuprea bark:Biological source:• Cuprea bark is obtained from Remijia purdieana

Traina and R. pedunculata Fluckiger of Rubiaceae family.

• The plant is a tree.Constituent:• It yields about 2-6% alkaloids containing• One third quinine• Quinidine and cuprea bark is the major

commercial source of quinidine.Use:• Quinidine is used as cardiac depressant.

Isoquinoline alkaloids:• The Isoquinoline alkaloids ring occurs in a

member of alkaloids in widely separated plant families. For example: Papaverine, Morphine, Emetine etc.

N

Isoquinoline nucleus

N

O

O

H3C

H3C

O

O

CH3

CH3

Papaverine

O

N CH3

OHHO

Morphine

O

N CH3

OHO

Codeine

H3C

Biosynthesis of Isoquinoline alkaloids:• From phenylalanine of tyrosine Phenylethylamine

derivatives and phnylacetaldehyde derivatives are obtained which are condensed to give Isoquinoline alkaloids.

• Morphine (and codeine, thebaine) is also formed from tyrosine (2 molecules) and in the biosynthetic pathway Norlaudanosoline is a key intermediate.

COOH

NH2HO

+COOH

NH2HO

NH

HO

HO

OH

OH

Norlaudanosoline

2 Tyrosine

Reticuline

Salutaridine

Thebaine

Codeine Morphine

N

O

O

H3C

H3C

O

O

CH3

CH3

Papaverine

Opium/gum opium:Biological source:

• The air dried milky exudates obtained by incising the unriped capsules of Papaver somniferum Linne of Papaveraceae family.

• The plant poppy is an annual herb with large, showy, solitary, flowers having color of pink to purple.

ConstituentsMore than 30 alkaloids are found in opium. The most important are the alkaloids• Morphine: It is the most important opium alkaloid. It is a

phenanthrene derivative containing an alchoholic and phenolic OH group. Morphine and its salts occur as white silky crystals, odorless and having a bitter taste. They are classified as narcotic analgesics and are strong hypnotic and narcotic. Their use tends to induce habit formation as well as common side-effects as nausea, vomiting and constipation.

• Codeine: It is the most widely used opium alkaloid. It is obtained from opium, or by methylation of morphine or by appropriate reduction and demethylation of thebaine. If methyl group replaces the hydrogen of phenolic OH in morphine it becomes codeine

• The drug and its salts are narcotics and antitussives. They are used as sedatives especially in allaying coughs. Its action is similar to that of morphine but is less toxic.

• Heroin: Diacetylmorphine or heroine is formed by acetylation of morphine, where the hydrogen atoms of both the phenolic and alchoholic hydroxyl groups are replaced by acetyl groups. Its action is similar but more pronounced than that of morphine. Due to its potency and the danger of habit formation it is not used in medicine.

• Noscapine• Thebaine• Papaverine

Also contains alkaloids like• Narceine• Protopine• Laudanine• Codamine• Cryptopine• Lanthopine• Mecondine

Use: The drug acts on CNS and first stimulates then depresses nerve response. It serves as• Analgesic• Hypnotic• Narcotic

IpecacBiological source:

• It is dried rhizomes and roots of Cephaelis ipecacuanha A. Richard (known as Rio ipecac) and C. acuminate (panama ipecac)of Rubiaceae family.

• The plants are low, straggling shrubs with slender rhizomes bearing annulated wiry roots.

Constituents:• Ipecac yields 2-2.5% alkaloids (not less than 2%)

containing 5 alkaloids 3 of which are• Emetine• Cephaeline• Psychotrine

Use:• It is emetic and used in poisoning treatment• It is also used in amoebic dysentery.

Sanguinaria/ blood root:

Biological source:• It is dried rhizome of Sanguinaria Canadensis Linne

of papaveraceae family. The plant is a perennial herb with horizontal branching rhizome that bears slender.

Constituents:It contains protopine alkaloids like• Sanguinarine (1%)• Chelerythrine• Protopine• AllocryptopineUse: As stimulating expectorant and emetic

Curare/South American arrow

poison:Biological source:• It is the dried crude extrac from the bark and stems

of Strychonos castelnaei Weddell, S. toxifera Bentham , S. crevauxii G. Planchon of Loganiaceae family and Chondodendron Tomentosum Ruiz et Pavon of Menispermaceae family.

• The plants are trees.Constituents:• It contains several alkaloids and quaternary

compounds. Specific composition varies with the plant material and preparation method. But (+/-) Tubocurarine is the most important constituent.

Use:

• Indians used it as poisons.• Curare is rarely used in medicine but (+/-)

tubocuratine chloride is used as a skeletal muscle relaxant in surgery and to control convulsions of strychinine poisoning and of tetanus.

Indole alkaloids:• A number of important alkaloids possess an

indole ring in their structure. For example: Strychnine, Reserpine, Brucine, Vinblastine, Vincreistine etc.

NH

Indole

NH

NH3CO

H3COOC

OCH3

O

C

OOCH3

OCH3

OCH3Reserpine

Biosynthesis of Indole alkaloids

• The precursor of indole alkaloids is tryptophan and monoterpenoid skeleton.

• Alkaloids like reserpine, serpentine are synthesized from tryptamine and corynanthe monoterpenoid precursor.

• The ergot alkaloids are synthesized by alkylation of Tryptophan by DMAPP as illustrated below:

NH

Tryptophan

OPP

+

H2N

COOH

Dimethyl allylpyrophosphate

NH

H2N

COOH

Dimethyl allyl tryptophan

Cyclization

Ergoclavine

Elymoclavine

Oxidation

NH

N

HOOC CH3

Lysergic acid

Ergonovine

Ergotamine

Ergot/Rye ergot/Secale cornutumBiological source:Ergot is obtained on a commercial scale from both parasitic and saprophytic source.

• Parasitic source: It is the dried selerotium (resting body of the ergot fungus given next) plants (Secale cerale Linne. Of Graminae family).

• Saprophytic source: In this case the ergot alkaloids are obtained from the fermentation broth in which the mycelium of selected strains of Claviceps Paspali Stervens & Hall has been grown saprophytically in submerged culture.

Constituents:• Ergot contains no less than 0.15% total alkaloids. It

contains a large number of alkaloids. The most important ones are

• Ergonovine (principlal water soluble alkaloid)• Ergotamine• Ergotoxine (mixture of egocristine, ergokrypine,

ergocornine)

Significant semsynthesis alkaloids include• Methylergonovine• Dihyddroergotamine• Hydergine

Use:• Ergonovine is an oxytocic, producing stimulation

of the uterine muscle. It is used for the prevention and treatment of postpartum hemorrhage due to uterine atony.

• Ergotamine is used as a specific analgesic in migraine.

Rauwolfia serpentineBiological source:

• Rauwolfia serpetina is the dried root of Rauvolfia serpentina (also Rauwolfia serpentina) Bentham ex Kurz of Apocynaceae family.

• The plant is an erect shrub that reaches 1 m in height and has cylindric stems.

Constituents• Three series of alkaloids have been reported• Weakly basic Indole alkaloids: Reserpine, Resinnamine,

Deserpidine etc.• Intermediately basic indole alkaloids: ajmaline, isoajmaline,

rauwolfinine etc.• Strong anhydronium bases: serpentine, serpentinine,

alstonine etc.

Use:

• Hypotensive• The chief alkaloid reserpine is antihypertensive

and used and tranquilizer drug.

Nux-vomicaBiological source:

• Nux-vomica is the dried, ripe seed of Strychnos nux-vomica Linne of loganiaceae family.

• The plant is a small tree of about 12m.Constituents

• It contains about 1.5-5% alkaloids.• Strychinine (chief constituents, about ⅓rd of total

alkaloid content)• Brucine• Isostrychnine etc.

Use:

• Strychnine is extremely toxic due stimulant effects and used as insecticide

• Brucine is less toxic and used as alcohol denaturant

Catharanthus/VincaBiological source:

• It is dried whole plant of Catharanthus roseus G. Don (formerly vinca rosea Linne) of Apocynaceae family.

• The plant is an erect ever blooming pubescent herb or subshrub attaining 40-80 cm and iti is widely cultivated as ornamental plant. The flowers of the plant are violet, rose or white.

Constituents:More than 70 alkaloids have been isolated. Important alkaloids are Indole Dihydroindole derivatives like• Vinblastine• Vincristine• Vinleurosine• Vinrosidine• Also contains• Ajmalicine• Tetrahyddroalstonine• Serntine• Lochnerine etc.

Use:

• Catharanthus has anticancer properties• Vinblastine is used in Hodgkin disease and

choriocarcinoma• Vincristine is used in the treatment of leukemia in

children

Imidazole Alkaloids• Imidazole ring occurs in the alkaloids Pilocarpine,

Isopilocarpine etc.

N

NH

ImidazoleN

N

OO

C2H5CH3

H2C

Pilocarpine

PilocarpusBiological source:• It consists of the leaflets of Pilocarpus jaborandi

Holmes, P. microphyllus stapf or P. pinatifolius Lamaire of Rutaceae family.

Constituents: It contains• Pilocarpine• Isopiocarpine• Pilosine• Isopilosine etc.Use: The principal constituent Pilocarpine is used to great glaucoma

Steroidal Alkaloids• The steroidal alkaloids are characterized by the

cyclopentanoperhydrophenanthrene nucleus. The important alkaloids Protoveratrine A &B, Aconitine, Conessine etc.

Cyclopentanoperhydrophenanthrene

Example:

NH3C

CH3

CH3

N

CH3

CH3

Conessine

Veratrum viride/green hellebore

Biological source:It is dried rhizome and roots of Veratrum viride of Liliaceae family. • It is a perennial herb attaining 0.7 to 2 m height.

Constituents:• It contains a large number of alkaloids as follows-• Esters of alkamines (steroidal bases): Germidine, germitrine,

cevadine, protoveratrine etc.• Glucosides of alkamines: Pseudojervine, veratrosine.• The alkamines: Jervine, rubijervine, germine etc.

• Among them germidine and germitrine are most important therapeutically.

Use:• It possesses hypotensive, cardiac depressant and

sedative properties.• It is used in the treatment of hypertension.• As insecticide.

Veratrum album/ white hellebore

Biological source:• It is dried rhizomes of Veratrum album Linne of

Liliaceae family. It is also a perennial herb but the external color is lighter compare to V. viride.

Constituents:• Similar to V. viride. Two ester alkaloids protoveratrine

A and B are most active.

Use: • It has hypotensive properties• As insecticides

AconiteBiological source:• It is dried tuberous roots of Aconitum napellus of

Renunculaceae family. The plant is perennial herb.

Constituents:• It contains aconitine, aconine and aconitic acid etc.

Use:• Has cardiac effect but• Principally used as local analgesic in liniments

Alkaloidal Amino Group

• The alkaloids in this group do not contain heterocyclic nitrogen atoms. For example: Colchicine. Some are derivatives of Phenylethylamine like Ephedrine, Mescaline etc.

CH2CH2NH2

Phenylethylamine

Example

NHCH3

CH3

OH

Ephedrine

CH2CH2NH2H3CO

H3CO

OCH3

Mescaline

NHCOCH3

OCH3

H3CO

H3CO

OCH3

O

Colchicine

Ephedra/ Ma huangBiological source:• It is the entire plant or the overground portion of Ephedra sinica stapf

of Gnetaceae family. • The plant is a low, dioecious (male and female reproductive organs on

different plants) practically leafless shrub that attain 60-90 cm height.

Constituents:• The important constituent is ephedrine. It may also contain

pseudoephedrine and some other related compounds.

Use:• Ephedrine is a potent sympathomimetic (excites the sympathetic

nervous system).• It raises blood pressure and causes mydriasis and act as

bronchodilator.

Colchicum SeedBiological source:• It is dried, ripe seed (or corn) of Colchicum autumnale Linne

of Liliaceae family.• Two to six flowers with long perianth tube develop from the

underground plant. The arabs had recommended the use of colchicum in the treatment of gout.

• Constituents:• It contains colchicine, colchicine like alkaloids, resin, fixed oil

and reducing sugars. The seed contains upto 0.8% colchicine (corn contains 0.6% colchicine).

• Use:• It is in the treatment of gout.

Lupinane Alkaloids• The alkaloids in the group contain a dicyclic

Lupinane structure/ring . For example: Sparteine, Lupinine etc.

N

Lupinane

N

Lupinine

CH2OH

LupinusBiological source:• Lupinus is obtained from Lupinus luteus of

Fabaceae family.• The plant is an annual herb and cultivated as

ornamental plant.

Constituents• Important constituents is Lupinine.

Use:• Not medicinally important.

ScopariusIt is the dried tops of Cytisus coparius of Leguminosae family.

Constituents:• Its main constituents are Lupinane alkaloids

including Sparteine and flavonoids.

Use:• It is and oxitoxic and is used in the treatment of

uterine inertia.

Purine Alkaloid• The alkaloids in this group contain the Purine

nucleus which consists of the six membered Pyridine ring fused to the five membered Imidazole ring.

• The important examples in this group are Caffeine, Theobromine etc.

N

N

N

N

H

Purine

N

N

N

N

CH3

H3C

O

O

CH3

Caffeine

Coffee/CoffeaBiological source:• It is dried, ripe seeds of Coffea Arabica Linne of Rubiaceae family.• The plant is small evergreen tree or shrub.

Constituents: It contains:• Caffeine (1-2%)• Trigonelline (0.25%)• Tannin (3-5%)• Sugar (15%)• Fatty oil (10-13%)• Protein (10-13%)

Use:• Caffeine is the main principle which is CNS stimulant.

Tea/TheaBiological source:• Tea is the prepared leaves or leaf buds of Camelia Sinensis O. Kuntze of Theaceae

family.• It is shrub or small tree with alternate, evergreen leaves.

Constituents:• Tea contains:• Caffeine (1-4%)• Adenine• Theobromine• Theophylline• Xanthine• 15% gallotannic acid• 0.75% of a yellow volatile oil.

Use:• As beverage• As smooth muscle relaxant attributed to theophylline

CocoaBiological source:• It is obtained from the dried, ripe seeds of Theobroma cacao Linne

of Sterculiaceae family. The plant is a moisture loving rainforest tree.

Constituents:• It contains• Theobromine• Caffeine• Cocoa butter

Use:• It is a nutrient, stimulant and diuretic.• Theobromine is diuretic and smooth muscle relaxant• Cocoa butter as base for semisolid drugs.

Exraction of alkaloids

Powderd Materials

Free alkaloids and other plant constituents

Organic layer containing alkaloids and other plant constitutents

Aqueous layer containing

alkaloidal salts

Precipitaion of free alkaloids

organic layer containing other

organic compounds

Aqueous layer containing water soluble compounds

Process-I

Description• The powdered material is moistened with aqueous alkali

[water and mixed with lime which combines with acids, tannins and other phenolic substances and sets free the alkaloids (if they exist in the plant as salts)].

• The alkaloids are set free with other plant constituents.• Extraction is then carried out with organic solvents such as

Benzene or chloroform (either or petroleum spirit). • The concentrated organic liquid which contains alkaloids and

other plant constituents is then dilute acid (aqueous acid) and allowed to separate.

• Alkaloid salts are now in the aqueous liquid, while many impurities remain behind in the organic liquid.

• Aqueous alkali is added to the aqueous layer giving precipitation of free alkaloids.

Powderd Materials

Aalkaloidal salts and other plant constituents

Organic layer containing pigments and other Organic compounds.

Aqueous layer containing Alkaloidal salts

Precipitation of free alkaloids

Process-IIMoisten with water or aqueous alcohol containing dilute acids

Extract with organic solvent like Benzene, Chloroform etc.

Add aqueous alkali

Description• The powdered material is extracted with water of

aqueous alcohol containing dilute acid. • We get Alkaloidal salts and other plant constituents.• Pigments and other unwanted materials are

removed by shaking with chloroform or other organic solvents.

• Then we get aqueous layer containing Alkaloidal salts.

• The free alkaloids are then precipitated by the addition of aqueous alkali (excess sodium bicarbonate or ammonia) and separated by filtration or by extraction with organic solvents.