This document provides an introduction to secondary metabolites called alkaloids. It discusses the history, definitions, properties, chemical tests, classifications, occurrences and distributions of various alkaloids. Key points include that alkaloids are basic nitrogen-containing compounds found in plants, true alkaloids contain heterocyclic nitrogen rings, they are classified based on their ring structure (e.g. isoquinoline, indole), and examples are given of commonly used alkaloid-containing plants and their active constituents.

1. INTRODUCTION TO SECONDARY METABOLITES
SATYAJIT GHOSH
B. PHARM 4TH
SEMESTER

2. ALKALOIDS
Alkaloids are a chemically. heterogeneous group of natural substances and comprise more than 6000
basic nitrogen containing organic compounds which occur in about 15% of all vascular terrestrial plants and in
more than 150 different plant families.
 History: -
i. The term alkaloid' was coined by Meisner, a German pharmacist in 1819.
ii. The French chemist, Derosne in 1803, isolated narcotine. In the same year, morphine from opium was
isolated by Serturner.
iii. Pelletier and Calverton from the Faculty of Pharmacy in Paris isolated emetine in 1817 and colchicine
in 1819.
iv. This was followed by isolation of series of alkaloids from vegetable drugs, like strychnine (1817);
brucine, piperine and caffeine (1819); quinine, colchicine and cinchonine (1820); coniine (1826),
papaverine (1821) and thebaine (1835).
 Definition: -
i. The term is derived from the word alkali-like and hence, they resemble some of the characters of
naturally occurring complex amines.
ii. 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.
iii. 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.
iv. Proto alkaloids or amino alkaloids are simple amines in which the nitrogen is not in a heterocyclic ring.
Sometimes, they are considered as biological amines. Some of the examples of these alkaloids are
mescaline, N, N-dimethyltryptamine, colchicine and ephedrine.

3. v. The term pseudoalkaloids include 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 pseudo alkaloids are conessine and caffeine.
 Properties: -
 Physical properties: -
i. All the alkaloids are colorless, crystalline solids with a sharp melting point or decomposition range.
ii. Some alkaloids are amorphous gums, while others like coniine, sparteine, nicotine etc., are liquid
and volatile in nature.
iii. Some alkaloids are colored in nature, e.g., betanidin is red, berberine is yellow and salts of
sanguinarine are copper red in color.
iv. In general, the free bases of alkaloids are soluble in organic non-polar, immiscible solvents. The
salts of most alkaloids are soluble in water. In contrast, free bases are insoluble in water and the
salts are also very sparingly soluble in organic solvents. The alkaloids containing quaternary base
are only water soluble. Some of the pseudo alkaloids and proto alkaloids show higher solubility
water. For example, colchicine is soluble in alkaline water, and caffeine is freely soluble in water.
Quinine hydrochloride is highly soluble in water i.e. 1 part of quinine hydrochloride is soluble in
less than 1 part of water, while only 1 part of quinine sulphate is soluble in 1000 parts of water.
 Chemical Properties: -
i. Most of the alkaloids are basic in reaction, due to the availability of lone pair of electrons on
nitrogen. The basic character of the alkaloidal compound is enhanced if the adjacent functional
groups are electron releasing.
ii. The alkaloid turns to be neutral or acidic when the adjacent functional groups are electron
withdrawing like amide group which reduces the availability of the lone pair of electrons.
iii. The alkaloids may contain one or more number of nitrogen and it may exist in the form as primary
(R – NH2), e.g. mescaline; secondary amine (R2 – NH), e.g. ephedrine; tertiary amine (R3N) e.g.
atropine; and quaternary ammonium compounds (R4N+
X) e.g. tubocurarine chloride.

4.  Chemical tests for alkaloids (Identification test): -
i. The qualitative chemical tests used for detection of alkaloids are dependent on the characters of
alkaloids to give precipitates as salts of organic acids or with compounds of heavy metals, like mercury,
gold, platinum, etc.
ii. Following reagents gives precipitates: -
Reagents Compositions Color of precipitate
Mayer’s reagent Potassium mercuric iodide
solution (K2HgI4)
Cream color
Dragendroff’s reagents Potassium bismuth iodide
solution (BiI4K)
Reddish brown
Wagner’s reagent Iodine – potassium iodide
solution (IKI)
Reddish brown
Hager’s reagent & Picrolonic acid Picric acid Yellow color
iii. The chemical tests with heavy metals are not solely limited to alkaloids. Proteins, coumarins and α-
pyrone also give precipitate with these reagents. It may be also noted that some alkaloids do give such
tests, like caffeine which is highly water soluble. Hence, the tests with heavy metals in some cases
false positive reactions or false negative reactions.
 Classification of alkaloids: -
The various methods proposed for classification of alkaloid are as follows: -
A- Pharmacological Classification: -
 Depending on the physiological response, the alkaloids are classified under various
pharmacological categories, like central nervous system stimulant or depressant,
sympathomimetic, analgesics, purgatives, etc.
 Within the same drug, the individual alkaloid may exhibit different action e.g. morphine is narcotic
analgesic, while codeine is mainly antitussive. In cinchona, quinine is antimalarial, while quinidine
is cardiac depressant
B- Taxonomic Classification: -
 This method classifies the vast number of alkaloids based on their distribution in various plant
families like solanaceous or papilionaceous alkaloids.
 They are grouped as per the name at the genus in which they occur, e.g. ephedra, cinchona, etc.
From this classification, the chemotaxonomic classification has been further derived.

5. C- Biosynthetic Classification: -
 This method gives significance to the precursor from which the alkaloids are biosynthesized in the
plant. Hence, the variety of alkaloids with different taxonomic distribution and physiological
activities can be brought under same group, if they are derived from same precursor e.g. all indole
alkaloids from tryptophan are grouped together.
 The alkaloidal drugs are categorized on the fact whether they are derived from amino acid
precursor as ornithine, lysine, tyrosine, phenylalanine, tryptophan, etc.
D- Chemical Classification: -
 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: -
a- Heterocyclic alkaloids (True alkaloids) are divided into twelve groups according to nature of
their heterocyclic ring.
b- Non-hetero-cyclic alkaloids or proto-alkaloids or biological amines or pseudo alkaloids.
Type
Examples
(Active Constituents)
Basic ring structure
Heterocyclic Alkaloids (True Alkaloids)
Pyrrole and
Pyrrolidine
Hygrine,
coca species
Pyridine and
Piperidine
Arecoline,
anabasine,
coniine,
lobeline,
pelletierine,

6. Pyrrolizidine
Echimidine,
senecionine,
seneciphylline,
symphitine
Tropane
(piperidine N-methyl
pyrrolidine)
Atropine,
hyoscine,
hyoscyamine,
cocaine,
pseudo-pelletierine,
meteloidine
Quinoline
Quinine,
Quinidine,
Cinchonine,
cinchonidine,
cupreine,
camptothecin
Isoquinoline
d-tubocurarine,
berberine.
emetine,

7. cephaeline,
papaverine,
narcotine,
narceine
Phenanthrene
Morphine,
codeine,
hydrastine
Aporphine
(reduced isoquinoline
naphthalene)
Boldine
Indole
(Benz pyrrole)
Ergometrine,
ergotamine.
reserpine,
vincristine,
vinblastine,
strychnine,
brucine,
physostigmine

8. Imidazole
Pilocarpine,
Iso-pilocarpine,
Pilosine
Norlupinane
Cytisine,
laburnine,
lupanine,
sparteine
Purine
(pyrimidine/imidazol
e)
Caffeine,
theobromine,
theophylline
Steroidal
(cyclopentanoperhydr
ophenanthrene ring)
Protoveratrine,
solanidine,
conessine,
funtumine
Non-heterocyclic alkaloids Pseudo alkaloids
Diterpene
Aconitine,
Aconine,
hypoaconitine

9. Proto Alkaloids (Amino Alkaloids)
Alkylamine
(Amino alkaloid)
Ephedrine,
pseudoephedrine
Mescaline,
colchicine
 Occurrence & Distribution of Alkaloids: -
Name of drug
and synonym
Biological source Active
constituents
Uses
Indole Alkaloids
Ergot
(Ergot of Rye)
A fungal sclerotium of Claviceps
purpurea, Family Hypocraceae
In ovary of rye plant Secale
cereale. family Graminae
ergometrine
ergotamine
Oxytocic, prevents
postpartum
hemorrhage: used in
treatment of migraine
Nux vomica
(Crow Fig)
Seeds of Strychnos nux vomica,
Loganiaceae
strychnine, brucine CNS stimulant, bitter
stomachic, tonic
Physostigma
(Calabar beans)
Seeds of Physostigma
venonosum, Loganiaceae
Physostigmine,
physovenine
cholinergic,
(ophthalmic) in
glaucoma
Sarpagandha
(Rauwolfia)
Roots and rhizomes of
Rauwolfia serpentina,
Apocynaceae.
reserpine,
rescinnamine
hypotensive
tranquillizer
Vinca
(Catharanthus)
Entire plant of Catharanthus
roseus, Apocynaceae
vincristine,
vinblastine
anticancer (treatment
of Hodgkin's disease
and leukemia)
Isoquinoline Alkaloids
Curare
(South American
arrow poison)
Dried extract of stems & leaves
of various plants from family
Loganiaceae
and Menispermaceae
d-tubocurarine
chloride
skeletal muscle relaxant
Daruhaldi
(Berberis)
Roots and rhizomes of
Berberis aristata,
Berberidaceae
berberine
astringent in
inflammation of
mucous membranes
Ipecacunha
(Ipecac)
Roots and rhizomes of
Cephaelis ipecacuanha and C.
acuminate, Rubiaceae
Emetine, cephaeline
antiamoebic, emetic,
expectorant
Opium
(Raw opium)
Dried latex from the capsules of
Papaver somniferum,
Papaveraceae
narcotine,
papaverine
narcotic analgesic, in
diarrhea
Tropane Alkaloids
Belladonna herb
(Deadly night shade
Leaf)
Dried leaves and flowering tops
of Atropa belladonna,
Solanaceae
hyoscyamine,
atropine
anticholinergic.
antispasmodic

10. Coca leaves
Dried leaves of Erythroxylon
coca, Erythroxylaceae
cocaine, cinnamyl
cocaine,
α-truxilline
local anesthetic
Datura
(Angel's trumpet)
Dried leaves and flowering tops
of Datura metel var. fastuosa,
Solanaceae
scopolamine,
hyoscyamine,
atropine
anticholinergic, in
duodenal ulcers
Duboisia
(Cork-tree)
Dried leaves of Duboisia
myoporoides, Solanaceae
scopolamine anticholinergic
Hyoscyamus
(Henbane)
Dried leaf and flowering top of
Hyoscyamus niger,
Solanaceae
hyoscyamine,
hyoscine
anticholinergic,
antispasmodic
Stramonium
(Thorn apple
leaves)
Dried leaves and flowering tops
of Datura stramonium,
Solanaceae
l-hyoscyamine,
hyoscine, atropine
anticholinergic,
mydriatic, control
motion sickness
Quinoline Alkaloids
Camptotheca
(Cancer tree)
Camptotheca acuminatal
Nyssaceae
Camptothecin
Anti-tumor
Cinchona
(Peruvian bark)
Dried root or stem bark of
Cinchona calisaya,
C. officinalis,
C. ledgeriana
C. succirubra, Rubiaceae
quinine, quinidine,
cinchonine,
cinchonidine.
antimalarial,
bitter tone
Amino Alkaloids (Proto-Alkaloids)
Colchicum
(Meadow saffron
seed)
Seed and corm of Colchicum
autumnale, Liliaceae
Colchicine,
demecolcine
treatment of gout
induction of polyploidy
Ephedra
(Ma-Hoang)
Dried stems of Ephedra
gerardiana, E. equisetina,
E sinica etc., Ephedraceae
ephedrine
pseudoephedrine
(alkaloidal amines)
sympathomimetic anti-
asthmatic,
treatment of hay fever
Gloriosa
(Glory lily)
Dried rhizomes & roots of
Gloriosa superba,
Liliaceae
Colchicine
In the treatment of gout
& cancer
Pyridine Alkaloids
Areca nut
(Betal nut)
Dried ripe seed of Areca
catechu, Palmae
arecoline, arecaidine
respiratory stimulant
Lobeline
(Indian tobacco)
Dried leaves and tops of Lobelia
nicotianefolia,
Campanulaceae
lobeline,
lobelanidine
respiratory stimulant
Purine Alkaloids
Cocoa seed
(Cocoa beans)
Seeds of Theobroma
cocoa, Sterculiaceae
theobromine,
caffeine
diuretic
Coffee seed
Dried ripe seeds of Coffea
arabica, Rubiaceae
caffeine trigonelline
Stimulant to counter
effect over dosage of
CNS depressant
Kola
(Cola)
Seeds of Cola nitida,
Sterculiaceae
caffeine,
theobromine
CNS stimulant
Tea Leaves
(Camellia Thea)
Leaves and leaf buds of Thea
sinensis, Theaceae
caffeine,
theobromine
CNS stimulant and
diuretic

11. Imidazole alkaloids
Pilocarpus
(Jaborandi)
Dried leaves of Pilocarpus,
jaborandi, Rutaceae
Pilocarpine, pilosine
cholinergic
(ophthalmic), used in
treatment of glaucoma
Steroidal Alkaloids
Ashwagandha
(Asgandh)
Dried roots of Withania
somnifera, Solanaceae
withanine,
somniferine,
withanolide
(steroid)
sedative and also as
antirheumatic
Kurchi
(Hollarrhena)
Dried bark of Holarrhena
antidysenterica, Apocynaceae
Conessine,
iso-conessine
Antiamoebic
Veratrum
(white and green
hellebore)
Dried rhizomes of Veratrum
album and V. viride,
Liliaceae
germidine,
protoveratrine A and
B
Hypotensive depressant
Diterpene alkaloids
Aconite
(Monkshood)
Dried roots of Aconitum
napellus, Ranunculaceae
aconitine, neopelline
In treatment of
rheumatism and
Quinazoline alkaloids
Vasaka
(Adulsa)
Leaves of Adhatoda vasica,
Acanthaceae
vasicine and
vasicinone
Antitussives,
expectorant

12. GLYCOSIDES
 Definition: -
i. Glycosides may be defined as the organic compounds from plants or animal sources which on
enzymatic or acid hydrolysis give one or more sugar moieties along with non-sugar moiety.
ii. The sugar moiety is known as glycone and non-sugar moiety is known as aglycone.
iii. Many glycosides are used in traditional and modern medicines because of their cardiotonic, purgative,
analgesic, anti-rheumatic, demulcent and other useful actions.
iv. Chemically, they are the acetyls or sugar ethers, formed by interaction of hydroxyl group each of non-
sugar and sugar moieties, with a loss of water molecule.
v. The hydroxyl group of aglycones may be alcoholic or phenolic and in some cases from amines also.
vi. The sugars involved in glycosides are of different types, but most commonly, it is - D- glucose. The
other sugars found are galactose, mannose, rhamnose, digitoxose, cymarose, etc.
vii. The linkage between glycone and aglycones is called glycosidic linkage and on the basis of this linkage,
alpha and beta stereoisomers are assigned.
viii. In a simplest form, the glycoside with these two isomers can be synthesized from union of methyl
alcohol and glucose.
 Classification: -
The classification of glycosides is based either on the chemical nature of aglycone part or
therapeutic activity exhibited by the same. Another mode of classification is based on the type of
linkage existing between the glycone and aglycones part.
A- According to chemical nature of aglycones moiety, they are grouped into: -
Classes Examples
Anthraquinone or anthracene glycosides Senna, Rhubarb, Aloe
Sterols or cardiac glycosides Digitalis, Squill
Saponin glycosides Brahmi, Momordica
Cyanogenetic or cyanophoric glycosides Bitter almond, Wild cherry
Isothiocyanate glycosides Mustard seed
Flavonoids Flavonol glycosides Buck wheat, Ginkgo
Coumarins and Furanocoumarin glycosides Ammi, Visnaga, Mylabris
Aldehyde glycosides Vanilla

13. ∥
N – O – SO3 K
Phenol glycosides Bearberry
Steroidal glycoalkaloids Solanum
Glycosidal bitters or miscellaneous glycosides Chirayata, Gentian
B- Sometimes Glycosides are also classified on the basis of type of sugar or the glycone their structure.
Accordingly, there are glucosides with glucose, rhamnosides with the rhamnose, pentosides with
pentose like ribose, etc.
C- Another approach for their classification is by considering the linkage across glycone & aglycones part.
Basically, all types of glycosidal linkages are occurred by interaction of – OH group of glycone and
hydrogen coming through any of the radicals like – CH, - OH, - SH and -NH on aglycones part.
Hence, by elimination of one water molecule, linkage or a bridge is formed and the type of glycoside
formed is named by putting the element as prefix like C-glycoside, N-glycoside, O-glycoside or S-
glycoside.
A- C-glycosides (when sugar moiety is linked to carbon atom):
Some of the anthraquinone glycosides such as cascarosides from cascara and aloin from aloe, as
well as, some member of flavone type of glycosides shows the presence of C-glycosides.
Glycone – OH + H C – aglycones glycone – C – aglycones + H2O
C – glycosides, which are also called as aloin-type glycosides, are mainly present in members
Liliaceae, e.g. Aloe. They are not hydrolyzed by heating with dilute acids/alkalis, but by
oxidative hydrolysis with ferric chloride. Cochineal contains C-glycoside in the form of a coloring
matter called carminic acid.
B- O - glycosides (when sugar moiety is attached to oxygen atom):
They are very common higher plants e.g. senna, rhubarb, frangula, etc. They are hydrolysed by
treatment of acid or alkali into aglycones and sugar, i.e. glucoranillin, amygdaling.
Glycone – O H + HO – aglycones glycone O - aglycones + H2O
C- S – glycosides (when sugar is linked to sulphur atom):
Their occurrence is restricted to isothiocyanate glycosides like sinigrin from black mustard.
C3H5 − C – S – C6H11O5
They are formed by interaction of sulfhydryl group of aglycones and hydroxyl group of glycone.

14. Glycone – OH + H S – aglycone glycone - S - aglycones + H2O
D- N - glycosides:
The most typical representative example of N-glycosides is nucleosides, where the amino group
of base reacts with – OH group of ribose / deoxyribose and ultimately gives N-glycosidic form.
Glycone – OH + H N-Glycone Glycone – N – aglycone + H2O
 Properties: -
i. Glycosides are crystalline or amorphous substances which are soluble in water and dilute alcohol with
an exception of resin glycosides, but insoluble in organic solvent like chloroform or ether.
ii. The aglycones moiety is soluble in non-polar solvents like benzene or ether.
iii. Glycosides are easily hydrolysed by water, mineral acids and enzymes.
iv. They show optical activity, normally with levorotatory effects.
v. Glycosides do not reduce Fehling's solution until they are hydrolysed. They are believed to participate
in growth regulation and protection of plant.
 Test for Identification: -
 Chemical Tests for Anthraquinone Glycosides:
i) Borntrager's Test: -
1 gm of drug is boiled with 5-10ml of dilute HCI for 10 minutes on a water bath. After boiling the
solution is filtered, and the filtrate extracted using CCl4 / benzene. The extracted solution obtained
is shaken with an equal quantity of ammonia solution. A pink or red color appears in the
ammonical layer which confirms the presence of anthraquinone moiety.
ii) Modified Borntrager's Test: -
1 gm of drug is mixed with 5ml of dilute HCl and ferric chloride (5% w/v). The mixture is boiled
on a water bath for 10 minutes, cooled, and then filtered. The filtrate is extracted using CCl4 /
benzene. The extracted solution obtained is shaken with an equal quantity of ammonia solution. A
pink to red color appears which confirms the presence anthraquinone moiety (C-type of
anthraquinone glycosides).

15.  Chemical Tests for Saponin Glycosides: -
i) Hemolysis Test: -
A few drops of aqueous saponin solution are taken on a slide along with a drop of blood. The RBCs
will get ruptured due to the presence of saponins.
ii) Foam Test: -
1 gm of drug is shaken for a few minutes with 10-20 ml water. Formation of froth that remains for
60-120 seconds confirms the presence d saponins.
 Chemical Tests for Steroid and Triterpenoid Glycosides: -
i) Liebermann – Burchard Test: -
The alcoholic extract of drug is evaporated to dryness. The residue is extracted using CHCl3. To
the CHCl3 extract, a few drops of acetic anhydride and concentrated H2SO4 are added along the
wall of test tube. A ring of violet to blue color appears at the junction of two liquid that confirms
the presence of steroid moiety.
ii) Salkowski Test: -
The alcoholic extract of drug is evaporated to dryness. The residue is extracted using CHCI3. To
the CHCl3 extract, concentrated H2SO4 is added from the walls of the test tube. A yellow ring
appears at the junction of wo liquids, which changes to red after 2 minutes, thus confirms the
presence of steroid moiety.
iii) Antimony Trichloride Test: -
The alcoholic extract of drug is evaporated to dryness. The residue is extracted using CHCl3. To
the CHCl3 extract having 20% acetic anhydride, saturated solution of SbCl3, is added. A pink color
that forms on heating confirms the presence of steroids and triterpenoids.
iv) Trichloro Acetic Acid Test: -
On adding a saturated solution of trichloroacetic acid to triterpenes, a colored precipitate is
formed.

16.  Chemical Tests for Cardiac Glycosides: -
i) Keller-Kiliani Test: -
The alcoholic extract of drug is added with equal volume of water and 0.5 ml of strong lead acetate
solution, followed by shaking and filtering the resultant solution. The filtrate is extracted using
equal volume of chloroform.
The chloroform extract obtained is evaporated to dryness. The residue is dissolved in glacial acetic
acid (3ml) and a few drops of FeCl3 solution are added. The obtained solution transferred to a test
tube containing 2 ml of concentrated H2SO4.
A layer of reddish-brown color is formed which upon standing changes to bluish green, this
confirms the presence of digitoxose.
ii) Legal Test: -
The alcoholic extract of drug is shaken with an equal volume of water and 0.5 ml of strong lead
acetate solution. The resultant mixture is filtered, and the filtrate is extracted using chloroform in
equal parts.
The chloroform extract obtained is evaporated to dryness. The residue is dissolved in 2 ml each of
pyridine and sodium nitroprusside. The solution is made alkaline by adding NaOH solution. A pink
color appears that confirms the presence of glycosides or aglycone moiety.
iii) Baljet Test: -
On dipping either a thick section of leaf or other part of digitalis containing cardiac glycosides in
sodium picrate solution, yellow color changes to orange that confirms the presence of aglycones or
glycosides.
 Chemical Tests for Coumarin Glycosides: -
i) FeCl3 Test: -
The concentrated alcoholic extract of drug is added with a few drops of alcoholic FeCl3 solution. A
deep green color appears which changes to yellow when added with concentrated HNO3, thus
confirms the presence of coumarins.

17. ii) Fluorescence Test: -
The alcoholic extract of drug is added with 1 ml of 1 N NaOH solution. A blue-green fluorescence
appears that confirms the presence of coumarins.
 Chemical Tests for Cyanophoric Glycosides: -
i) Sodium Picrate Test: -
In a conical flask, the powdered drug is taken and moistened with water and a few drops of
concentrated H2SO4. A filter paper impregnated with sodium picrate solution and sodium
carbonate solution is fitted at the neck of the flask with a cork.
A brick red color appears due to volatile HCN that confirms the presence of cyanophoric
glycosides.
 Chemical Tests for Flavonoid Glycosides: -
i) Ammonia Test: -
A filter paper is dipped in alcoholic solution of drug and then exposed to ammonia vapours. A
yellow spot appears on the filter paper that confirms the presence of flavonoids.
ii) Shinoda Test: -
To the alcoholic extract of drug, magnesium turning and dilute HCl are added. A red color appears
that confirms the presence of flavonoids.
To the alcoholic extract of drug, zinc turning and dilute HCI are added. A deep red to magenta
color appears that confirms the presence of dihydro flavonoids.

18.  Occurrence & distribution of glycosides: -
Name of Drug
and synonym
Biological source
Active
constituents
Uses
Anthracene Glycosides
Aloes
(Kumari)
Dried juice of leaves of Aloe vera,
Aloe barbadensis, Aloe
ferox, Liliaceae
Barbaloin, Aloe,
Emodin
Purgative
Cascara
(Sacred bark)
Dried bark of Rhamnus
purshiana, Rhamnaceae
Cascarosides A, B, C
and D
Mild purgative
Hypericum
(Goat-weed)
Dried aerial parts of Hypericum
perforatum, Hypericaceae
Hypericin,
Hyperforin
Antidepressant
Rhubarb
(Rheum)
Dried rhizome of Rheum palmatum,
Polygonaceae
Rhein, aloe emodin
Purgative, bitter
stomachic
Alexandrian senna
(Senna leaf)
Dried leaflets of Cassia acutifolia,
Leguminosae
Sennoside A and B Purgative
Indian senna
(Senna leaf)
Dried leaflets of Cassia
angustifolia, Leguminosae
Sennoside A and B Purgative
Senna pods
(Senna-fruit)
Dried nearby ripe fruits of Cassia
acutifolia or C. angustifolia,
Leguminosae
Sennoside A and B Purgative
Steroidal Glycosides or Cardiac Glycosides
Digitalis
(Fox glove leaves)
Dried leaves of Digitalis purpurea,
Digitalis lanata, Scrophulariaceae
Purpurea glycoside A
& B, digitoxin,
lanatosides A, B and
C, digoxin
Cardiotonic
European squill
(Scilla)
Dried sliced bulbs of Urginea
maritima, Liliaceae
Scillaren A and B Cardiotonic
Indian squill
(Urginea)
Dried bulbs of Urginea indica Scillaren A and B Cardiotonic
Ouabain
Dried seeds of Strophanthus gratus,
Apocynaceae
Ouabain Cardiotonic
Strophanthus
(Arrow poison)
Dried ripe seeds of Strophanthus
kombe, Apocynaceae
Strophanthidin Cardiotonic
Thevetia
(Lucky-nut-tree)
Dried seeds of Thevetia nerifolia,
Apocynaceae
Thevetin Cardiotonic

19. Saponin Glycosides
Brahmi
(Bacopa)
Leaves and stems Bacopa
moniera, Scrophulariaceae
Bacosides A and B Nervine tonic
Dioscorea
(yam)
Dried Rhizomes of Dioscorea
deltoidea, Dioscoreaceae
Diosgenin (steroidal
sapogenin)
Synthesis of
medicinal
steroids
Ginseng
(Panax)
Dried root of Panax ginseng,
Araliaceae
Ginsenosides &
panaxosides
(triterpenoid
saponins)
Adaptogen tonic and
stimulant
Gokhru
(Tribulus)
Dried fruits Tribulus terrestris,
Zygophyllaceae
Steroidal sapogenins Diuretic
Jal Brahmi
(Centella)
Dried herb of Centella asiatica,
Umbelliferae
Asiaticoside Nervine tonic
Momordica
(Karela)
Dried fruits of Momordica
charantia, Cucurbitaceae
Charantin,
Momordicin
Hypoglycemic
Quillaia
(Soap bark)
Dried inner bark of
Quillaia saponaria, Rosaceae
Quillaia sapotoxin
(triterpenoid
saponin)
Reflex expectorant
Safed musali
Peeled tuberous roots of
Chlorophytum borovillianum
Liliaceae
Hicogenin General tonic
Senega
Dried roots of Polygala senega,
Polygalaceae
Senegin, polygallic
acid
(triterpenoid
saponin)
Stimulant
expectorant
Shatavari
(Shutmuli)
Dried roots and leaves Asparagus
racemosus, Liliaceae
Shatavarin I, II Galactogogue
Yasti
(Glycyrrhiza)
Dried roots and stolon of
Glycyrrhiza glabra, Leguminosae
Glycyrrhizin
(triterpenoid
saponin),
18 -β-glycyrrhetinic
acid
Expectorant
treatment of peptic
ulcer

20. Cyanogenetic & Cyanophoric glycosides
Bitter almond
Dried ripe seeds of Prunus
amygdalus, Rosaceae
Amygdalin Demulcent, sedative
Wild cherry
(Wild black cherry)
Dried bark of Prunus serotina,
Rosaceae
Prunasin
Mild sedative,
flavoring agent
Isothiocyanate Glycosides
Mustard seeds
(Black mustard)
Dried ripe seeds of
Brassica nigra, Cruciferae
Sinigrin
Counter irritant,
rubefacient
externally and
emetic internally
Flavonoids
Buckwheat
Dried fruits of Fagopyrum
esculentum, Polygonaceae
Rutin
Treatment of
capillary bleeding
Citrus fruits
Rind of unripe, green lemon fruits,
citrus lemonis or orange fruits
citrus aurantium, Rutaceae
Hesperidin
In capillary
fragility
Ginkgo
Dried leaves of Ginkgo biloba
Ginkgoaceae
Ginkgolide A, B, C Vascular disorders
Milk-Thistle
(Silymarin)
Dried seeds of
Silybus marianum, Asteraceae
Silybin Silycrystin Liver disorders
Coumarin and Furanocoumarin Glycosides
Ammi
Dried fruits of Ammi majus,
Umbelliferae
Xanthotoxin Treatment of vitiligo
Psoralea fruit
(Bavchi)
Dried ripe fruits of Psoralea corylifolia,
Leguminosae
Psoralen, corylifolin
Treatment of
leukoderma
Tonka bean
Dried seeds of Dipteryx odorata,
Leguminosae
Coumarin Flavoring agent
Visnaga
(Khella)
Dried ripe fruits of Ammi visnaga,
Umbelliferae
Khellin, visnagin
Smooth muscle
relaxant, coronary
vasodilator
Cantharides
(Spanish fly)
Dried beetles Cantharis
vasicatoria, Meloidae
Cantharidin
Counter irritant
Rubefacient
Cochineal
(Red scale insect)
Dried full-grown female insects
enclosing young larva of Coccus cacti,
coccidae
Carminic acid Coloring agent
Mylabris Dried female insects of
Mylabris pustulata
Cantharidin
Counter irritant,
Rubefacient

21. Aldehyde Glycosides
Anantmul
(Sariva)
Dried roots of Hemidesmis indicus,
Asclepiadaceae
Iso vanillin
Anti-inflammatory
flavouring agent
Vanilla
(Vanilla pods)
Unripe fruits of Vanilla
planifolia, Orchidaceae
Gluco – vanillin Flavouring agent
Phenol Glycosides
Bearberry
(Uva ursi)
Dried leaves of Arctostaphylos
uvaursi, Ericaceae
Arbutin Diuretic in urethritis
Steroidal Glyco-alkaloids
Solanum
Dried fruits of
Solanum khasianum, Solanaceae
Solasodine
For steroidal
synthesis
Glycosidal Bitters and Miscellaneous Glycosides
Chirata
(Chirayata)
Dried plant of Swertia chirata,
Gentianaceae
Gentiopicrin
Stomachic,
antipyretic
Garcinia
Dried de-seeded fruits Garcinia
combogia, Guttiferae
Hydroxy citric acid,
tartaric acid
Anti-rheumatic
condiment
Gentian
Dried roots of Gentiana lutea,
Gentianaceae
Gentiopicrin, amaro
gentin
Bitter stomachic,
tonic
Gudmar
(Gymnema)
Dried leaves of Gymnema sylvestre,
Asclepiadaceae
Gymnemic acid Anti-diabetic
Guduchi
Dried leaves and stems of
Tinospora cordifolia,
Menispermaceae
Tinosporoside
Cardiofoliside
Bitter tonic and
general debility
Henna Lawsonia inermis, Lythraceae Lawson Anti-fungal
Kalmegh
(Andrographis)
Dried leaves and tender shoots of
Andrographis paniculata,
Acanthaceae
Andrographolide
Bitter tonic
anthelmintic
Hepato-protective
Manjishta
Dried stems of Rubia cordifolia,
Rubiaceae
Rubiandin, purpurin
(anthraquinones)
In leukoderma and
in cosmetic products
to gain glow and
luster
Picrorrhiza
(Indian gentian)
Dried rhizomes of
Picrorrhiza kurroa,
Scrophulariaceae
Picroside I,
kutkoside, amaro
gentin
Bitter tonic.
Hepato-protective
bitter
Quassia
(Bitter wood)
Dried stem wood of Picrasma
excelsa, Simarubaceae
Picrasmin, quassin
Bitter stomachic
anthelmintic

22. Vajradanti
(Yellow nail dye
plant)
Barleria prionitis,
Acanthaceae
Saponin glycosides
prioniside A,
prioniside B,
Barlerinoside.
In treatment of
stiffness of
limbs, sciatica
to reduce obesity,
joint pains,
promotes hair
growth, urinary
infections

23. Flavonoids
 Definition: -
i. Flavonoids are defined as 'a large group of biologically active water-soluble plant compounds (such as
anthocyanins and flavones) that include pigments ranging in color from yellow to red to blue, and
occurring especially in fruits, vegetables, and herbs'.
ii. Chemically, flavonoids have the general structure of a 15-carbon skeleton, which consists of two
phenyl rings and a heterocyclic ring (C, the ring containing the embedded oxygen). This carbon
structure can be abbreviated C6-C3-C6.
 Classification: -
Classes Description Structure
Flavones
A benzo-gamma pyrone ring having a phenyl
substitution at position 2 in the ring is present. A
double bond between the 2 and 3 positions and a
ketone in the 4th position of C ring is present.
Vegetables and fruits having flavones
carry a hydroxyl group in 5th position of the A ring.
Isoflavone
A benzo-gamma-pyrone ring having a phenyl
substitution at position 3 in the ring is present.
Neoflavonoids Their B ring is linked to the C ring at 4th position.

24. Flavonols
These are diverse and multi-substituted subgroups
and are 3-hydroxy derivatives of flavone.
Flavanones
Their C ring is saturated, thus the double bond
between 2nd and 3rd positions is also saturated. This
makes flavones and flavanones structurally different.
The flavanones have the ability to be multi-
hydroxylated. Many hydroxyl groups can get
glycosylated or methylated.
Anthocyanidin
Chemically, they are flavylium cations and occur in
the form of chloride salts. The color imparting
attribute to the plants is only in this group of
flavonoids.
Anthocyanins are derived from anthocyanidins
glycosides. In anthocyanidins, the sugar moieties are
attached at the 3 position of the C ring, and are also
conjugated with phenolic acids (like ferulic acid).
The pH and also methylation or acylation at the
hydroxyl groups on A and rings influence the color of
anthocyanins.
Chalcones
Chalcones and dihydrochalcones have open
structures, and they fall under the category of
flavonoids since their synthetic pathways are similar
Flavanols or
Flavan-3-ol or
Catechins
Their hydroxyl group lies at the 3rd position of the C
ring, thus they are also named as flavan-3-ols.
They carry two chiral centers at 2nd and 3rd positions
of the molecule, thus have 4 possible diastereomers.
Epicatechin is an isomer having cis configuration,
while catechin has trans configuration.
These configurations also have 2 stereoisomers, i.e.,
(+) – epicatechin and (-) – epicatechin, (+) –
catechin and (-) – catechin.
The edible plant usually carries (+) – catechin and (-
) – epicatechin.

25.  Properties: -
a- They have an antioxidant effect as they can neutralise free radicals.
b- They act as a cardiotonic as they strengthen the heart muscles.
c- They have an anti-cancerous effect as they inhibit the growth.
d- They lower the cholesterol level in blood.
e- They are anti-inflammatory as they reduce inflammation.
f- They also act as anti-microbial agents.
 Test for Identification: -
A- Ammonia Test: -
A filter paper is dipped in an alcoholic solution of drug and is then exposed to ammonia vapours. A
yellow spot appears on the paper that confirms the presence of flavonoids.
B- Shinoda Test: -
The alcoholic extract of drug is added with magnesium turning and dilute HCL. A red colour appears
that confirms the presence of flavonoids.
C- Vanillin HCI Test: -
The alcoholic solution of drug is added with vanillin HCI. A pink color appears that confirms the
presence of flavonoids.
 Uses: -
a- They act as antioxidants.
b- Other beneficial effects are anti-viral, anti-cancer, anti-inflammatory, and anti-allergic.
c- A flavonoid known as quercetin improves eczema, sinusitis, asthma, and hay fever.
d- Studies have revealed that flavonoids lessen the possibility of heart disease, as these molecules prevent
the low-density lipoproteins to oxidize, thus reduce atherosclerosis development.
e- Some tea varieties carrying rich content of flavonoids lower triglycerides and cholesterol levels in
blood.
f- Soy flavonoids or isoflavones also decrease cholesterol. They also work against osteoporosis and
improve the symptoms of menopause.

26. Volatile Oil
 Definition: -
i. Volatile or ethereal oils are defined as, ‘odorous volatile principles of plant and animal origin which
evaporate when exposed to air at ordinary temperature’.
ii. As they evaporate when exposed to air at ordinary temperatures, they are also called as "ethereal oils.
They present essence or active constituent of plant, or animal hence they are also known as "essential
oils.
iii. Chemically, they are derived from terpenes and their oxygenated compounds. They are made up of
isoprene units (C6H8) and are usually mono-, sesqui- and di-terpenes.
 Classification: -
Types Examples
Alcohol volatile oils Peppermint, cardamom, coriander, orange flower oil, rose oil, sandalwood
Aldehyde volatile oils Cinnamon, lemon peel, orange peel, citronella oil, lemon-grass, bitter almond
Ester volatile oils Gaultheria, lavender, mustard
Hydrocarbon volatile oils Turpentine, black pepper
Ketone volatile oils Caraway, spearmint, buchu, camphor, musk, civet oil
Oxide volatile oils Chenopodium, eucalyptus
Phenolic ether volatile oils Anise, fennel, nutmeg
Phenol volatile oils Clove, thyme, creosote
 Properties: -
a- Volatile oils are soluble in alcohol, ether and other lipid solvents and practically insoluble in water.
b- They are usually lighter than water. They possess characteristic odors and they have high refractive
index.
c- Most of them are optically active. They are secreted in special structures such as duct, cell,
schizogenous or lysigenous glands, trichomes, etc.
d- They are commonly found in the species Labiatae, Rutaceae, Piperaceae, Zingiberaceae, Umbelliferae,
Myrtaceae and Lauraceae.

27.  Chemical tests for Volatile Oils: -
1. To the thin section of the drug, add alcoholic solution of Sudan III. Red colour obtained by globules
indicates the presence of volatile oil.
2. To the thin section of the drug add a drop of tincture alkane. Red colour indicates presence of volatile
oil.
 Occurrence of terpenoids in volatile oil: -
Volatile oil Terpenoids present
Caraway oil Carvone, and limonene
Citronella oil Geraniol, citronellal, farnesol
Eucalyptus oil Cineole
Geranium oil Geraniol
Peppermint oil Menthol
Ginger oil Zingiberene
Fennel oil Anethol
Sandalwood oil Santalol
Clove oil Eugenol
 Uses: -
Volatile oils are employed as flavouring agent, perfuming agent in pharmaceutical products, foods,
beverages, and in cosmetics. They serve as medicinal agents for therapeutic effects like:
1) Carminative (e.g., Umbelliferous fruits),
2) Anthelmintic (e.g., Chenopodium oil),
3) Diuretics (e.g., Juniper)
4) Antiseptic (e.g., Eucalyptus),
5) Counter irritant (e.g., Oil of winter green).
6) Local anesthetic (e.g., Clove)
7) Sedative (e.g., Jatamansi)

28. Resins
 Definition: -
It is defined as solid or semisolid, amorphous products derived from living natural sources mostly from the
hydrocarbon secretion of the various plants.
 Classification: -
Resins can be classified as follows: -
A- Resin acid: -
Carboxylic acid group containing resinous substances. Example: -Colophony (Abietic acid), Myrrh
(Commiphoric acid), Safetid (Sandracolic acid), Copaiba (Copaibic & Oxycopaibic acid), Shellac
(Alleuritic acid).
B- Resin ester: -
These are ester of resin acid or other aromatic acids like benzoic, cinnamic, salicylic acid. Example: -
Benzoin (Coniferyl benzoate), Storax (Cinnamly cinnamate).
C- Resin alcohol: -
Contains complex alcohols of high molecular weight. They are found either in free state or as ester.
Example: -Balsam of peru (Peruresinotannol), Gurjan balsam (Gurjuresinol), Guaiacum resin (Guaic
resinol).
D- Oleoresins: -
These resins occur along with the volatile oils. Some of the plants that contain oleoresins are
turpentine, capsicum, ginger, male fern, Canada balsam, and copaiba.
E- Gum Resin: -
These resins are present in plants along with the gums. Purification of gum raisins is done by
dissolving the gum in water. Gum resins are found in asafoetida, gambage, and myrrh.

29. F- Oleo-Gum Resins: -
These resins are present along with gums and volatile oils. Their purification is done by steam
distillation which removes the volatile oil, while removal of gum is done by dissolving it in water. The
typical plants containing oleo gum resins are myrrh and frankincense.
G- Glycoresins (Glucoresins): -
These resins are found to be naturally combined with the glycosides. Hydrolysis of glycoresins yields
sugar as a glycine part while complex resins as an aglycone part. Glycoresins are present in ipomoea,
scammony, jalap, and podophyllum
 Properties: -
a- They are brittle, hard and almost transparent.
b- Their specific gravity ranges from 0.9 - 1.25, which means they are heavier than water.
c- Most of them are amorphous in nature, but few can be crystallized also.
d- When heated at low temperature they become soft, but on further heating they melt into a sticky,
viscous liquid without decomposing or getting evaporated.
e- When heated in the presence of oxygen, they burn spontaneously resulting in a sooty flame. This is
due to the presence of a large number of carbon atoms.
f- When heated in the absence of oxygen, they get decomposed resulting in empyreumatic products
(characteristic burnt organic matter). These products contain hydrocarbons.
g- Usually they are insulators (bad electricity conductors), but attain a negative static charge on rubbing.
h- Due to their hydrophobic nature, they are insoluble in polar solvents like water, but freely soluble in
volatile oils, ethanol, fixed oils, chloral hydrate, and non-polar organic solvents, like benzene, n-
hexane, and petroleum ether.

30.  Test for Identification: -
 Colophony Resin: -
i. 100mg of resin powder is dissolved in 10ml acetic anhydride. To this solution few drops of sulphuric
acid are added which results in purple violet coloration of the solution
ii. Powdered resin is agitated with petroleum ether and then filtered. To the filtrate, double volume of
copper acetate (dilute) solution is added and again agitated. The solution obtained is allowed to
stand after which the ethereal layer attains emerald green colour.
 Guaiacum Resin: -
A solution of resin is prepared in ethanol and to this solution ferric chloride is added. This results in
deep blue coloration of the solution.
 Occurrence & distribution of resins: -
Name of crude
drug
Synonym Biological source
Active
constituents
Uses
Vegetable drugs
Asafoetida Devils drug
Ferula foetida,
Umbelliferae
Resin, gum, volatile
oil, asaresinotannol
Carminative,
nervine stimulant,
intestinal flatulence
Balsam of peru
Indian black
balsam
Myroxylon
balsamum,
Leguminosae
Resin, volatile oil,
esters of cinnamic
and benzoic acid
Scabies, wounds
flavouring agent
Benzoin Loban
Styrax benzoin,
Styrax tonkinesis,
Styraceae
Benzoic and
cinnamic acids and
their esters,
sumaresinolic and
siaresinolic acid,
coniferyl acetate
Expectorant,
carminative,
antiseptic
Boswellia Sallaki
Boswellia serrata,
Burseraceae
Resin, boswellic
acid, volatile oil
sesquiterpenes
Rheumatoid
arthritis
Cannabis Ganja
Cannabis sativa
Cannabinaceae
Resin, tetrahydro
cannabinol
Narcotic analgesic,
psychotropic
Capsicum Chilies
Capsicum annum,
Solanaceae
Capsaicin,
capsanthin,
carotene pigments
Stomachic,
counter irritant in
rheumatism,
lumbago
Capsicum
oleo resin
Capsicum extract
Capsicum annum,
Solanaceae
Capsanthin,
capsaicin
Powerful irritant,
ingredient of
capsicum plaster
Colocynth Bitter apple
Citrullus colosynthis,
Cucurbitaceae
Resin, alkaloids,
cucurbitacin E
Purgative

31. Colophony Rosina
Pinus species,
Pinaceae
Resin acids, abietic
acid resene
Stimulant diuretic
Ginger Zinziber
Zingiber officinale,
Zingiberaceae
Volatile oil,
zingiberene,
curcumene, resin,
gingerol, shogaols,
gingediols
Aromatic
carminative,
flavouring agent,
motion-in treating
sickness
Ginger oleo resin Gingerin
Zingiber officinale,
Zingiberaceae
Gingerol, shogaol,
zingerone
Flavor for
carbonated
beverages
Guggul Commiphora
Commiphora
Weightii,
Burseraceae
Gum resin, steroids,
guggulosterones
Anti-inflammatory,
hypolipidemic
Haridra
Haldi
(Turmeric)
Curcuma longa
(Zingiberaceae)
Volatile oil
curcuminoids
Anti-inflammatory
condiment, spice
Ipomoea Orizaba jalap
Ipomoea
orizabensis,
Convolvulaceae
Resin, jalapin Cathartic
Jalap Jalap radix
Ipomoea purga,
Convolvulaceae
Resin, volatile oil,
jalapin convolvulin
Powerful cathartic
Kaladana Pharbatis
Ipomoea
hederaceae,
Convolvulaceae
Resin (pharbiticin),
saponin
Cathartic
Male fern Aspidium
Dryopteris filix-mas,
Polypodiaceae
Oleo-resin,
phluroglucinol
derivatives, filicic
acid, flavispidic acid
Anthelmintic for
tape worms
Myrrh Gum-Myrrh
Commiphora
molmol,
Burseraceae
Volatile oil, gum,
commiphoric acid,
resin
Antiseptic,
stimulant
Nirgudi Monk's pepper Vitex nigundo Volatile oil
Anti-rheumatic,
Anti-inflammatory
Podophyllum
Indian
podophyllum
Podophyllum
hexandrum,
P. emodi,
Berberidaceae
Resin, podophyllin
peltatins
Purgative
treatment of
veneral worts,
anticancer
Podophyllum resin Podophyllin
Podophyllum
hexandrum,
P. emodi,
Berberidaceae
Resin,
podophyllotoxin
Drastic purgative,
treatment of
veneral worts
Storax Prepared storax
Liquidamber
orientalis,
Hemamelidaceae
Resin (storesin),
free and cinnamic
ester
Stimulant
antiseptic and in
perfumes
Tolu balsam Balsam of Tolu
Myroxylon
Balsamum,
Leguminosae
Cinnamic acid
benzoic acid,
benzoyl benzoate,
toluresinotannol,
volatile oil
Expectorant
flavouring agent,
antiseptic
Animal drug
Shellac Sealing wax
Lacifer lacca,
Lacciferidae
Resin, shelloic acid,
aleuritic acid
Sustained release
medicaments

32. Tannins
 Definition: -
i. They are the mixture of complex organic substances wherein polyphenols are present with o-dihydroxy
or o-trihydroxy groups on a phenyl ring.
ii. Normally, they have fairly high molecular weight and unlike alkaloids are devoid of nitrogen.
 Classification: -
The tannins are classified into three groups based on complexity of their chemical nature and according to
their behavior on dry distillation.
A- Hydrolysable tannins: -
i. These tannins are hydrolysed by acids or enzymes quickly and the products of hydrolysis are Gallic
acid or ellagic acid.
ii. On dry distillation, Gallic acid and other components get converted to pyrogallol. They respond to
ferric chloride solution, producing blue colour. The examples of hydrolysable tannins are
gallotannin in nutgall, rhubarb, clove and chestnut; ellagitannin from oak, myrobalans and
pomegranate bark.
B- Condensed tannins: -
i. They are also known as non-hydrolysable tannins, phlobatannins, proanthocyanidins.
ii. They are very resistant to hydrolysis. Being related to flavonoids pigments because they are formed
via derivatives of flavones, like catechin or flavan-3-ol or flavan-3,4-diols.
iii. On treatment with enzymes or mineral acids, they are polymerized or decomposed into red colored
substances called phlobaphenes, which are insoluble in water and indicate the typical brownish-
red colour of many plants and drugs.
iv. On dry distillation they yield catechol, with ferric chloride tannins produce brownish-green colour.
v. They are distributed in different parts of plants. The green tea and hamamelis leaves; cinchona,
cinnamon and wild cherry bark; male fern rhizome; cocoa, cola and areca seeds; pale and black
catechu are rich in condensed tannins.

33. C- Pseudo tannins: -
i. These may be treated as subgroup because they do not obey to Goldbeater's skin test and are low
molecular weight compounds.
ii. Chlorogenic acid in coffee and nux vomica, ipecacuanhic acid in ipecacuanha and catechins in
cocoa are examples of pseudo tannins.
iii. The detection test for chlorogenic acid is carried out by extracting the drug with water and
treating this extract with ammonia solution, followed by exposure to air, which leads slowly to
formation of green colour.
 Properties: -
1) They have a sharp puckering taste (astringent taste).
2) They are non-crystallizable.
3) They are soluble in water, dilute alkalis, alcohol, glycerol, and acetone; but sparingly soluble in other
organic solvents.
4) They form colloidal solution by an acid reaction when reacted with water.
5) Mostly they cause precipitation of alkaloids, glycosides, gelatin, and heavy metal salts of copper, lead,
and tin.
6) They form dark blue or greenish black soluble compounds when treated with ferric chloride solution.
7) They give a deep red coloration when treated with potassium ferricyanide and ammonia.
8) They make the proteins resistant to proteolytic enzymes by combining with them.
9) They are complex, organic, non-nitrogenous compounds derived from polyhydroxy benzoic acid found
to be widely distributed in the vegetable kingdom.
 Identification test: -
Tannins exhibit some specific chemical reactions: -
(1) Solution of tannin precipitates gelatin, and alkaloids.
(2) Tannins are precipitated by salts of copper, tin, and lead.
(3) They are precipitated by strong potassium dichromate solution or chromic acid solution.

34. (4) They show colour reactions with iron salts. Ferric chloride gives bluish-black or brownish green
colour; potassium ferricyanide with ammonia gives deep red colour.
(5) Goldbeater's skin test: Goldbeater's skin is a prototype of untanned fresh skin of an animal and is
obtained as a membrane from the intestine of ox. This membrane is treated with hydrochloric acid,
rinsed with distilled water and then placed in tannin solution for 5 minutes. It is followed by
washing with distilled water and keeping in ferrous sulphate solution. Tannin imparts brown or
black colour to the skin.
(6) Tannins are precipitated by a 2 % solution of phenazone, the tannin solution being prepared with
sodium acid phosphate.
 Occurrence & distribution: -
Name of drug &
synonym
Biological source Active constituents Uses
Hydrolysable tannins
Amla
(Indian goose
berry)
Dried as well as fresh fruits of
Emblica officinalis,
Euphorbiaceae
Vitamin C,
phyllemblin,
tannins
Diuretic, laxative,
ingredient of Triphala
and
Chyavanprash
Arjuna
Dried stem bark of
Terminalia arjuna,
Combretaceae
Ellagic acid, β-
sitosterol
Cardiotonic,
hypotensive
Bahera
(Bellaric
myrobalan)
Dried ripe fruits of
Terminalia belerica,
Combretaceae
Gallic acid, chebulagic
acid
Astringent, ingredient
of triphala churna
Myrobalan
(Harda)
Dried mature fruits of
Terminalia chebula,
Combretaceae
Chebulic acid,
chebulagic acid, Gallic
acid
Astringent, stomachic,
purgative, ingredient of
triphala churna
Tannic acid
Fermented oak galls which are
grown on young twigs of
Quircus infectoria,
Fagaceae
Gallic acid and
glucose
Astringent for mucous
membrane

35. Condensed tannins
Amra
(Mango)
Dried bark of Mangifera indica,
Anacardiaceae
Tannins, catechin
mangiferin
Antioxidant,
antidiarrhoeic
Ashoka bark
Dried stem bark of Saraca
indica, Leguminosae
Catechol, ketosterol Uterine tonic, oxytocic
Black catechu
(cutch)
Dried aqueous extract of
heartwood of Acacia catechu,
Leguminosae
Acacatechin,
quercetin
Astringent for boils,
skin eruptions
Pale catechu,
(Gambier)
Dried aqueous extract of
leaves and young shoots of
Uncaria gambier,
Rubiaceae
Catechin,
catechutannic
acid
Astringent for
treatment
diarrhea
Pterocarpus
(Indian kino)
Dried juice of the plant
Pterocarpus marsupium,
Leguminosae
Kinotannic acid, kino
red, k-pyrocatechin
Hypoglycemic,
powerful astringent