• “Basic nitrogenous compound, contains one or more
nitrogen in heterocyclic ring system having marked
physiological action on human and animals when use in small
Classification of alkaloids
• 1. Chemical classification of alkaloids
• 2. Taxonomical classification of alkaloids
• 3. Pharmacological classification of alkaloids
• 4. Biosynthetic classification of alkaloids
4. BIOSYNTHETIC CLASSIFICATION OF
Alkaloids are classified on the basis of biosynthetic
precursors from which these are obtained . These
Ornithine derived alkaloids
Tryptophan derived alkaloids
Lysine derived alkaloids
Phenylalanine derived alkaloids
Tyrosine derived alkaloids
Histidine derived alkaloids
Alkaloids derived from substance other than amino
5. General reactions for biosynthesis of alkaloids
• Some of the general reactions that are of particular
importance include: decarboxylation (removal of
carboxyl group or carbon dioxide) and transamination
(transfer of an amino group from one molecule to another
without the formation of ammonia) of the amino acids to
yield a corresponding amine or aldehyde.
• These can react to form a Schiff base which, in turn can
react with carbanion in a Mannich-type condensation.
6. Alkaloid formation may require the involvement of only one
molecule of amino acid, or 2 molecules of the same AA, or
less commonly, 2 molecules of different AA or else several
molecules of the same AA.
9. TROPANE ALKALOIDS
(ATROPINE, HYOCYAMINE, HYOSINE, SCOPOLAMINE)
B.S: Atropa belladona (deadly nightshade), Datura stramonium( thornapple), Hyosyamus
Part used: dried leaves and flowering tops
Uses: 1.Atropine is classified as anti cholinergic drugs.
Atropine can also be used in SLUDGE syndrome( salivation, lacrimation, urination,
diaphoresis, GIT motility and emesis) caused by organophosphate poisoning.
Hyoscine is used as antispasmodic.
o B.S: Erythroxylum coca, Erythroxylum novogranatense
o Common name. Coca leaves
o Family: Erythroxylaceae
o Part used: Leaves
o Uses: cocaine is a CNS stimulant.
it is also used as local anesthetic.
13. Indole alkaloids
• Botanical source. Physostigma venonosum
• Common name: calabar bean
• Family : Leguminosae
• Part used: dried ripe seeds
• Main constituents: physostigmine ,
• Uses: These are the cholinesterase
inhibitors and used as antidote for atropine
• Also used to treat glaucoma.
B.S: Claviceps purpurea
Part used: Dried sclerotium of the fungus
Main constituents: Ergotamine,
Uses: Ergotamine is used to treat migraine
and clustur headache.
Ergometrine acts as oxytocic agent
and also used in post-partal haemorrhage.
B.S: Catharanthus roseus
Common name: periwinkle
Part used: whole plant
Constituents: Vincristine, Vinblastine
Uses: these alkaloids have anticancer
B.S: Rauwolfia serpentina
Common name: indian snakeroot
Part used: leaves
Constituents: serpentine, reserpine,
Uses: used as antihypertensive and
15. Quinoline alkaloids
B.S: Cinchona Succirubra, C. calisaya, C.
Common name; Quina
Part used: Dried Bark
Constituents: Quinine, quinidine, cinchonine,
Uses: Quinine is a classical antimalarial.
Quinidine is used for cardiac arrythmias
and atrial fabrillation.
17. Lobelia alkaloids
• B.S: Lobelia inflata
• Common name: indian tobacco
• Family: Lobeliaceae
• Part used: dried aerial parts
• Constituents: lobeline, isolobeline,
• Uses: it is used in chronic bronchitis and
18. Pepper alkaloids
• B.S: Piper nigrum
• Common name: black pepper, kali mirch
• Part used: dried , unripe fruit
• Family : Piperaceae
• Constituents: piperine and piperittene
• Uses: piper is used as condiment and for chronic bronchitis.
20. Papaver alkaloids
• B.S: Papaver somniferum
• Family: papaveraceae
• Part used: dried milky latex of poppy
• constituents: Morphine, codiene,
thebaine, Norcotine, Narciene,
• Uses: Morphine is used as analgesic.
codiene is used in cough preparations.
Common name: Ipecac
Part used: roots and rhizome
Constituents: cephaline, psychotrine,
Uses: ipecacuanha is used as expectorant,
and emetic and in the treatment of
22. Alkaloids derived from phenylalanine
• EPHEDRINE, PSEUDOEPHEDRINE :-
• B.S –It consists of dried young stem of Ephedra
gerardiana and Ephedra nebrodensis.
• Family:- Ephedraceae
• C.C:-- It contains the amino alkaloids :
Ephedrine, nor-ephedrine, n-methyl ephedrine,
• Uses: it is used in Asthma, hay fever, flu, cold
25. It is used in the treatment of glaucoma and atropine poisoning.
26. Alkaloids obtained from precursors other than Amino Acids
Purines are derivatives of a heterocyclic nucleus consisting of a
six-membered Pyrimidine ring fused to a five-membered
Purines are Psudo alkaloids (Are not derived from amino acids
but have nitrogen in a heterocyclic ring)
• B.S. Theobroma cacao
• Family: sterculiaceae
• Part used: seeds
• Uses: Cocoa has nutritive,
stimulant and diuretic
Theobromine is used as a
diuretic. It has less action on
the central nervous system
than caffeine but is more
B.S: Coffee arabica
Uses: caffeine is used in
analgesics, cold and flu
also used as Ingredient