Alkaloids,

Alkaloid
Definition, classification, properties and test for identification
PRESENTED BY:
MR. PRITAM VIJAY JUVATKAR
ASSISTANT PROFESSOR
pvjuvatkar@rediffmail.com, +91 9987779536
KONKAN GYANPEETH RAHUL DHARKAR COLLEGE OF PHARMACY AND RESEARCH INSTITUTE,
KARJAT
UNIVERSITY OF MUMBAI

Pritam Vijay Juvatkar 9987779536 Alkaloid 2
Definition
 Alkaloids the term is derived from the word 'alkali-like' These are the organic products of natural or
synthetic origin which are basic in nature and contain one or more nitrogen atoms, normally of
heterocyclic nature, and possess specific physiological actions on human or animal body, when used
in small quantities.
 The term 'alkaloid' or 'Pflanzenikalien' was coined by Meissner, a German pharmacist, in 1819.
 The mankind has been using alkaloids for various purposes like poisons, medicines, poultices, teas,etc.
 The French chemist, Derosne in 1803, isolated narcotine.
 Morphine from opium was isolated by Serturner, a pharmacist of Paderborn near Hannover in 1803.
 Pelletier and Caventon from the Faculty of Pharmacy in Paris isolated emetine in 1817 and colchicine in 1819.
 Strychnine (1817);
 Brucine, Piperine And Caffeine (1819);
 Quinine, Colchicine And Cinchonine (1820);
 Coniine (1826),
 Papaverine (1821) And Thebaine (1835).
Alkaloid

Pritam Vijay Juvatkar 9987779536 Alkaloid
3
True alkaloid
 The true alkaloids are toxic in nature, contain heterocyclic nitrogen which is derived from amino acids and
always basic in nature.
 True alkaloids are normally present in plants as salts of organic acids.
Proto or amino alkaloid
 The 'proto alkaloids' or 'amino alkaloids' are simple amines in which the nitrogen is not in a heterocyclic ring.
 Some times, they are considered as biological amines.
 They are basic in nature and prepared in plants from amino acids.
 Some of the examples of these alkaloids are mescaline, N-N-dimethyl tryptamine, colchicine, and ephedrine.
Alkaloid

Pseudoalkaloids
 The term 'pseudoalkaloids' includes mainly steroidal and terpenoid alkaloids and purines.
 They are not derived from amino acids.
 They do not show many of the typical characters of alkaloids, but give the standard qualitative
tests for alkaloids.
 The examples of pseudoalkaloids are conessine and caffeine.
Alkaloid

Physical Properties of Alkaloid
 Alkaloids are colourless, crystalline solids with a sharp melting point or decomposition range with few
exceptions.
 Some alkaloids are amorphous gums, whiIe others like coniine, sparteine, nicotine etc. are liquid and volatile in
nature.
 Alkaloids are coloured in nature, e.g. betanidin is red, berberine is yellow
 The free bases of alkaloids are soluble in organic non-polar, immiscible solvents and insoluble in water .
 The salts of most alkaloids are soluble in water and very sparingly soluble in organic solvents.
 The alkaloids containing quaternary bases are only water soluble.
 Some of the pseudoalkaloids and protoalkaloids show higher solubility in water.
 Colchicine is soluble in alkaline water, acid or water
 Caffeine (free base) is freely soluble in water.
 Quinine hydrochloride is highly soluble in water
Alkaloid

Chemical Properties of Alkaloid
 The alkaloids exist either in free state, as amine or as salt with acid or. alkaloid N:oxides.
 Basic in reaction, due to the availability of lone pair of electrons on nitrogen.
 It will enhanced if the adjacent functional groups are electron releasing.
 It turns to be neutral or acidic when the adjacent functional groups are electron withdrawing.
 The alkaloids may contain one or more number of nitrogen
 Primary (R - NH2), e.G. Mescaline;
 Secondary amine (R2 - NH), e.G. Ephedrine;
 Tertiary amine (R3N) E.G. Atropine
 Quaternary ammonium compounds [R4N+Xl E.G. Tubocurarine chloride.
Alkaloid

Classification of Alkaloids
 This is the most accepted way of classification of alkaloids. The main criterion for chemical
classification is the type of fundamental (normally heterocyclic) ring structure present in
alkaloid. The alkaloidal drugs are broadly categorized into two divisions.
 Heterocyclic alkaloids (True alkaloids) are divided into twelve groups according to
nature of their heterocyclic ring.
 Non-hetero-cyclic alkaloids or Protoalkaloids or Biological amines or pseudoalkaloids.
Alkaloid

Classification of Alkaloids-: Heterocyclic Alkaloids (True AIkaloids)
1. Pyrrole and Pyrrolidine
2. Imidazole
3. Pyrrolizidine
4. Pyridine and Piperidine
5. Tropane (piperidine. N-methyl pyrrolidine)
6. Quinoline
7. Isoquinoline
8. Norlupinane
9. Indole (Benz pyrrole)
10. Purine (pyrimidine/imidazole)
11. Phenanthrene
12. Aporphine (reduced isoquinoline-naphthalene)
13. Steroidal ( Cycloheptano-perhydrophenanthrene ring)
14. Diterpene
15. Amino alkaloid

1. Pyrrole and Pyrrolidine
3. Pyrrolizidine
Coca :Erythroxylon coca Cocaine,
α-Truxilline
2. Imidazole
Pilocarpus: Pilocarpus jaborandi
Pilocarpine, Pilosine
Echimidine, senecionine,

4. Pyridine and Piperidine
Lobelia: Lobelia nicotianefolia
Lobeline, lobelanidine
Areca: Areca catechu
Arecoline, arecaidine
5. Tropane (piperidine. N-methyl pyrrolidine)
Belladonna: Atropa belladonna
Atropine, l-hyoscyamine
Datura : Datura Metal
Atropine, l-hyoscyamine

6. Quinoline
8. Norlupinane
Cinchona : Cinchona officinalis
Quinine, quinidine, isoquniline,
Camptotheca: Camptotheca acuminatal
Camptothecin
7. Isoquinoline
Ipecacunha: Cephalis acuminate
Emetine, cephaeline
Berberis: Berberis aristata
Berberine
Cytisine, Laburnine, lupanine,
Sparteine containing in aconite

9. Indole
Ergot: Claceps purpurea
Ergometrine, Ergotamine
Vinca: Catharanthus roseus
Vincristine, vinblastine
10. Purine
Coffee: Coffee Arabica
Caffeine,
Tea: Thea sinesis
Caffeine, Theobromine

11. Phenanthrene
Opium: Papaver somniferum
Morphine, codeine
12. Aporphine
It is known as reduced
isoquinoline naphthalene
Boldine

Classification of Alkaloids-: Non-Heterocyclic True AIkaloids
Kurchi:Holarrhena antidysenterica
Kurchicine, conessine
13. Steroidal ( Cyclopentano-perhydrophenanthrene ring)
14. Diterpene
Aconite: Aconitum napellus,
Aconitine, neopelline
Classification of Alkaloids-: Pseudo alkaloid

Classification of Alkaloids-: Proto alkaloid
13. Amino alkaloid
Ephedra: Ephedra gererdiana
Ephedrine, pseudoephedrine
Colchicum: Colchicum autumnale
Colchicine, demecolcine

Chemical Test of Alkaloid
1. Dragendorff's reagent (potassium bismuth iodide solution) Reddish brown precipitate
2. Mayer's reagent (potassium mercuric iodide solution) Cream coloured precipitate;
3. Wagner's reagent (iodine-potassium iodide solution) Reddish brown precipitate.
4. Hager's reagent (picric acid ) Yellow coloured precipitates

Thank You
PRESENTED BY:
ASSISTANT PROFESSOR
KARJAT

Disclosure
PRESENTED BY:
ASSISTANT PROFESSOR
KARJAT
This Presentation is meant for Study Notes for B.Pharm Students only.
Please do not take as a reference for treatment for an ailments or other
usage

Alkaloids,

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Alkaloids,