History Introduction Definition Distribution and Occurence Physical & Chemical Properties Chemical tests

1. FACULTY NAME:SWATHI GARIGANTI
ASSISTANT PROFESSOR
SREE DATTHA INSTITUTE OF PHARMACY
SUBJECT:PHARMACOGNOSY&PHYTOCHEMISTRY-II
B.PHARMACY III-I SEMESTER

2. History
Introduction
Definition
Distribution and Occurence
Physical & Chemical Properties
Chemical tests

3. Origin, History, Introduction:
⋄ The term ʽ ʼ or ʽ ʼ was coined by Meissner, a German pharmacist,
in 1819. The mankind has been using alkaloid for various purposes like poisons,
medicines, poultices, teas etc.
⋄ The French Chemist ,Derosne in 1803,isolated narcotine.In the same year morphine from
opium was isolated by Serturner.In 1817 and 1819,Pelletier and Caventon fom the Faculty
of Pharamcy in paris Isolated Emetine and Colchicine.
⋄ As per Russian review in 1973,the number of known alkaloids had reached upto
4959,amongest which,the structures of 3293 alkaloids are elucidated.At present ,the
number of alkaoloids discovered has exceeded 6000.
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4. Definition :
⋄ 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.
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5. Distribution and occurrence:
 Abundant in higher plants(angiosperms).
 Families rich in Alkaloids: Apocynaceae,Rubiaceae, Solanaceae and
Papaveracea.
 Families free from Alkaloids: Rosaceae, Labiatae.
Distribution in Plant:
 Plant aerial part e.g.Ephedra(ephedrine),Bark e.g.Cinchona(quinine),enitre
plant vincae.g.(vincristine and vinblastine),Leaves of tea(Caffeine),Seeds
e.g.Nux vomica(strychnine) Fruitse.g. Black pepper(piperine),Latexe.g.Opium
(Morphine,Codeine) etc.
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6. Forms of Alkaloids:
Free bases,Salts with Organic acids e.g. Oxalic, acetic acids etc.Salts with inorganic
acids e.g. HCl, H2SO4.
Salts with special acids:
e.g. Meconic acid in Opium .
e.g.Quinic acid in Cinchona
Glycosidal form e.g. Solanine in Solanum.
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7. Physical properties:
I-condition :
 Most alkaloids are crystalline solids.
 Few alkaloids are amorphous solids e.g.emetine.
 some are liquids that are either:
 volatile e.g.nicotine and coniine or
 Non-volatile e.g.pilocarpine and hyoscine
II-color:
 The majority of alkaloids are colorless but some are colored e.g.
 colchicine and berberine are yellow,canadine is orange.
 The salts of sanguinarine are copper-red.
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8. III-Solubility:
 Both alkaloidal bases and their salts are soluble in alcohol.
 Generally the bases are soluble in organic solvents and insoluble in water.
Exceptions:
 Bases soluble in water:caffeine,ephedrine,codeine,colchicine,pilocarpine and
quaternary ammonium bases.
 Bases insoluble or sparingly soluble in certain organic solvents:Morphine in
ether,theobromine and theophylline in benzene.
Salts are usually soluble in water and insoluble or sparingly soluble in organic
solvents.
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9. Exceptions:salts insoluble in water:quinine monosulphate
salts soluble in organic solvents :lobeline and apoatropine hydrochlorides are soluble
in chloroform.
IV-isomerization:optically active isomers may show different physiological activities.
l-ephedrine is 3.5 times more active than d-ephedrine.
l-ergotamine is 3-4 times more active than d-ergotamine.
d-Tubocurarine is more active than corresponding l-form.
Quinine (l-form)is anti-malarial and its d-isomer quinidine is anti-arrythmic.
The racemic (optically inactive)dl-atropine is physiologically active.
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10. Chemical properties:
I-Nitrogen:
Primary amines R-NH₂ e.g. Norephedrine
secondary amines R₂-NH e.g.Ephedrine
tertiary amines R₃-N e.g.Atropine
quaternary ammonium salts e.g.d-Tubocurarine
II-Basicity
R₂NH> R-NH₂> R₃-N
Saturated hexacyclic amines is more basic than aromatic amines.
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13. CHEMICAL TESTS FOR ALKALOIDS:
Most alkaloids are precipitated from neutral orslightly acidic solution by
Dragendorff's reagent (solution of potassium bismuth iodide)reddish brown coloured
precipitate.
Mayer's reagent (potassium mercuric iodide solution) Cream coloured
precipitate.
Wagner’s reagent (iodine in potassium iodide) red-brown precipitate
Hagers reagent (picric acid) yellow precipitate
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14. THANK YOU