alkaloids-240409175554-5c09aae9 9098.pdf

Alkaloids

1. ALKALOIDS
Mr Nandakishor B. Deshmukh.
Assistant Professor
Shraddha Institute Of Pharmacy, KondalaZambre,
Washim.
Subject -Pharmacognosy And Phytochemistry -I
Class-B-pharm-II Sem IV
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SR NO Content
01Introduction
02Function Of Alkaloids
03Properties Of Alkaloids
04Classification Of Alkaloids
05Chemical Tests

3. ALKALOIDS
Alkaloids are a class of naturally occurring organic
compounds that mostly contain basic nitrogen atoms.
This group also includes some related compounds with neutral
and even weakly acidic properties.
Alkaloids are derived from plant sources they are basic they
contain one or more nitrogen atoms (usually in a heterocyclic
ring) and they usually have a marked physiological action.
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4. Function of alkaloids
they may function as stimulants or regulators
in activities like growth, metabolism and
reproduction.
They may act as reservoirs for protein
synthesis.
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5. Properties of alkaloids
Alkaloids are colourless, crystalline, non-volatile, solids, a few
such as coniine and nicotine are liquids and a few even coloured,
viz. berberine is yellow.
The free bases (i.e. alkaloids themselves) are insoluble in water
but soluble in most of the organic solvents. Most of the alkaloids
are laevorotatory (optically active), although a few are
dextrorotatory (e.g. coniine), while a few are even optically
inactive, viz. papaverine.
the alkaloids are bitter in taste and have pronounced physiological
activity.
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6. Classification of alkaloids
a.Taxonomicclassification-Onthebasisoftaxonomicprofileofthe
drug.Forex.Solanaceousalkaloids.
b.Biogeneticclassification-Onthebasisofaminoacidprecursor.For
ex.Phenylalanine,Tyrosinealkaloids
c.Pharmacologicalclassification-Onthebasistherapeuticactivityof
thealkaloidForex.Morphineasanalgesic,Quinineasantimalarial.
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7. d.Chemicalclassification-Onthebasisofbasicchemicalstructureofalkaloid.Itisof
furtherthreetypes-
1.Truealkaloid-Thealkaloidswhichhaveallbasicpropertiesofalkaloids,derivedfrom
aminoacidandcontainNitrogeninheterocyclicring.Ex.Atropine,Morphine.
2.Protoalkaloid-Thealkaloidinwhichnitrogenatomisnotpresentinthering,butitis
presentoutsidetheringIformofaminogroup,soalsocalledaminoalkaloidsor
biologicalamines.Ex.Ephedrine.
3.Pseudoalkaloids-Actuallythesearenotalkaloids.Thesearenotderivedfromamino
acidandnotgivebasicidentificationtestsofalkaloids.TheseareSteroidal(Solanine),
Terpenoidal(Diterpenealkaloid)andPurinealkaloid(Caffeine).
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8. chemical classification of alkaloids
1.Non-HeterocyclicAlkaloids
Groups Example Source Uses
Phenyl ethyl amine
alkaloid
Ephedrine, Mescaline
Hordenine
Ephedra sp.
Lophophora wiliamsoil
Asthama
Tropolone alkaloids Colchicine Colchicum sp. Gout
Modified diterpene Taxol Taxus sp. Anti cancer
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9. 2.HeterocyclicAlkaloids
A.Mono-nuclearHeterocyclicAlkaloids
Groups Example Source Uses
Pyridine Lobeline Lobelia sp. Asthama
Piperidine Piperine Piper sp Antioxidant
Pyrrole Hygrine Coca sp. CNS Stimulant
Pyrrolidine Nicotine Tobbaco sp CNS Stimulant
Imidazole Pilocarpine Pilocarpus Contraction pupil of
B.Poly-nuclearHetero-cyclicalkaloids
Isoquinoline Morphine,papaverine Opium Narcoticanalgesic
Quinoline Quinidine,quinidine Cinchona Anti-malarial
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10. Chemical tests
Reagent Composition Remarks
Alkaloid Precipitants
Mayer's Potassium-mercuric iodide Immediate creamy white ppt.(+ve
with most alkaloids except Caffeine
and dil. Ephedrine
Wagner's Iodine in potassium Reddish brown
Hager's
Dragendorff's
Iodide
Saturated soln. of picric acid
Yellow
Orange-reddish brown
Marme's Potassium bismuth iodide
Potassium cadmium iodide
Yellow
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