The document discusses primary and secondary metabolites, alkaloids, glycosides, and tannins. It defines these compounds and outlines their key properties. Alkaloids are nitrogen-containing compounds that have physiological effects. They are classified based on biosynthetic pathways, pharmacology, taxonomy, and heterocyclic ring structures. Glycosides are compounds containing a sugar and non-sugar moiety. They are classified by the type of sugar or aglycone. Tannins are polyphenolic compounds that can combine with proteins. They are classified as hydrolysable or condensed based on their chemical structures. Extraction and isolation methods are also presented.

1. Presented By
Miss Pooja D. Bhandare
Assistant Professor
Kandhar College of Pharmacy

2.  PRIMARY AND SECONDARY METABOLITE
 PRIMARY METABOLITE
1. Widely distriuted in nature practically in all
oraganism
2. Directly involved in growth, development
and reproduction.
2. They are not poisonous.
3. Example Carbohydrate, lipids, proteins and
amino acid.
 SECONDARY METABOLITE
1. Biosynthesized derived from primary
metabolites more limited distributed in
taxanomic plant.
eg. Reserpine from Rauwolfia serpentine
2. They do not directly involved in the normal
growth, development and reproduction
3. Some of these compounds are poisonous
4. Example Alkaloids, Glycosides, tannins,
Volatile oil , Resins and Resins
combination

3.  Alkaloids
 Coined by W. Meissner German Pharmacist in 1819.
 The term derived from the word “alkali like” so they have some character similar to
naturally occurring complex amines.
 Defination
 Alkaloids are the organic products of plant origin, basic in nature and contain one or more
nitrogenous atoms normally of heterocyclic in nature, and have marked physiological
action when administered internally

4.  GENERAL PROPERTIES OF THE ALKALOIDS
 PHYSICAL PROPERTIES
 Colourless, Crystalline solid and posses a sharp melting point
Some alkaloids like nicotine and connine are liquid and volatile in nature.
Some alkaloids are coloured like berberine is yellow and bentanidin is red.
 Solubility: Free alkaloids bases are fairly soluble in O S, Non polar solvent and lower alcohol and practically
insoluble OR sparingly soluble in water.
salt alkaloids are freely soluble in water, less soluble in alcohol and very springily soluble in organic solvent.

5.  CHEMICAL PROPERTIES
 The normal elements present in the alkaloids are carbon, hydrogen and oxygen
but every alkaloid should essential contain at least one nitrogen imparts for basic
properties.
 Chemical Test
1. Mayer’s reagents: Potassium – Mercuric iodide solution gives cream coloured
precipitate
2. Wagner’s reagents: Potassium Tri iodide solution gives reddish brown
precipitate.
3. Dragendorff’s reagent: Potassium bismuth iodide solution gives reddish brown
precipitate or Orange red precipitate.
4. Hager’s reagent: Saturated solution of picric acid gives Yellow coloured
precipitate.

6.  CLASSIFICATION OF ALKALOIDS
 Biosynthetic Classification:
 Pharmacological Classification
 Taxonomic Classification
 Chemical Classification

7.  Biosynthetic classification
 Given to the Precursor from which the alkaloids are produced in plant biosynthetically.
 So all the alkaloids derived from the same precursor can be brought under same group even they have
different taxonomic distribution and pharmacological activity.
 e. g. piperidine alkaloids derived from lysin, pyrrolidin alkaloids derived from ornithin and indole derived
from tryptophan.
 Pharmacological Classification
 Classification depends upon Pharmacological action e.g. CNS stimulant or depression and anti malarias etc
 Individual alkaloids may exhibit different action within the same drug for e.g. in cinchona, quinine is an anti
malarial where as quinidine is a cardiac depressant. In opium morphine is narcotic analgesic where as codine
is antitussive.

8.  Taxonomic classification:
 Classification deals with the ‘Taxon’
 Like genus, subgenus, species and subspecies etc
 Large number of alkaloids are classified on their like various family like rubiaceous
alkaloids and solanceous alkaloids.
 Some phytochemist have stepped further and classified alkaloids based on
chemotaxonomic classification

9.  Chemical Classification
 Widely accepted classification of alkaloids.
 The basic of classification is the ring structure (normally heterocyclic ring) present in the alkaloids.
Divided into two categories.
1. Non Heterocyclic or Proto alkaloids.
2. Heterocyclic or typical alkaloids.
 Large number of alkaloids which posse heterocyclic ring structure are mentioned below
 Type Example
1. Pyrrolidine Hygrine Stachydrine
2. Pyridine Ricinine, Arecoline
3. Piperdine Lobeline, Connine
4. Tropane Atropine, Cocaine
5. Quinoline Cinchonine, Quinine, Qunidine
6. Isoquinoline Papaverine, Morphine,Emetine

10.  GENERAL METHODS OF EXTRACTION AND
ISOLATION OF ALKALOIDS
 Methods 1 :-
Drug (Powdered) Moisten with H2O extracted with organic solvent Filtrate
&treated with lime (Petroleum spirit or ether)
Add water Separate Shaken with aqueous Reject the organic layer Aqueous layer
Organic layer acid(allow to separate) (Contains the
alkaloids salts.
Filter

11.  Methods 2:-
Drug (Powdered) Moisten with H2O extracted with alcohol Filtrate
&treated with acid or water
Add acetone Reject the organic layer Aqueous layer ammonia or sodium
(Contains several impurities) (contains alkaloids) bicarbonate
Add organic Reject the aqueous layer Organic layer contains
Solvent alkaloids
Filter
Treated with

12.  FUNCTIONS OF ALKALOIDS IN PLANT
 They may have a vital role in growth regulatory factor.
 The alkaloids are poisonous in nature thus they protect the plant grazing
animals or insects
 They act as a reserve substance in plant and supply nitrogen or other
elements.
 They might be the by-product of various detoxification reaction in plants
and by this way they cease the formation of harmful substance in plant.
 They are present in association with plant acid like quinic acid,
cinchotannic acid etc. Hence they may provide the means of storing or
transportation of such acids.

13.  GLYCOSIDES
 Defination
 The organic compounds mainly of plant origin and rarely of animal which
on enzymatic or acid hydrolysis yields one or more sugar
moieties(Glycon) and a non sugar moieties (Aglycon or Genin).
 The sugar (glycon) present in glycosides are monosaccharides like
glucose, rhamnose and rarely deoxysugars such cymarose found in cardiac
glycosides.
 The aglycon part may be alcohol, phenol or amines.
 The linkage between glycon and and aglycon is know as glycosidic
linkage.

14.  Properties
 Colourless but some them are coloured like flavonoids are yellow and anthracene
glycosides are red.
 They are crystalline or amorphous solid compounds.
 Glycosides are optically active and normally levo form is more active
 Soluble in water and alcohol but insoluble insoluble in chloroform and
ether.
 Glycosides can be hydrolysed by mineral acid, water and enzymes.

15.  ISOLATION-(STAS-OTTO METHOD)
Powder crude drug
Extracted with alcohol and
filter it
Residue Filtrate
(Tannis+Impurities+Glycosides)
Add lead acetate solution
(Excess of lead acetate is precipitated
by passing hydrogen sulphide gas)
Filter it
Tannin and Impurity Filtrate
Fractional crystallization
Fraction Solubility Chromatography
Pure glycoside

16.  Classification
1. On the basis of the type of the sugar or the glycone part e.g. glucoside with glucose, fructoside with
fructose and pentosides with pentose etc.
2. Glycosides are classified on the basis of the pharmacological action exhibited by them For e,g
Purgative glycosides – Aloe, Senna
Cardiac glycosides – Digitalis, Thevetia
Diuretics – Gokhru
3. Glycosides are also classified on the basis of linkage between glycone and aglycone part
A. O- glycosides- In these glycosides sugar is connected to OH or phenol group
-OH + HO-C6H11O5 -O-C6H11O5 + H2O
Example- Rhubarb and Senna etc
B. C- glycosides – In this type of glycosides sugar is connected to carbon atom
CH + HO-C6H11O5 -C-C6H11O5 + H2O
Example- Aloe and Cascara

17. C. S- glycosides – In this type of glycosides sugar is connected to sulphur of SH group
-SH + HO-C6H11O5 S-C6H11O5 + H2O
Example- Sinigrin from black mustard
D. N- glycosides – In this type of glycosides sugar is connected to nitrogen of NH group
N-H + HO-C6H11O5 N-C6H11O5 + H2O
Example- Nucleosides
4. Glycosides classified on the basis chemical nature
1) Anthracene glycoside
2) Saponin glycosides
3) Cardiac glycosides
4) Cyanogenetic glycosides
5) Isothiocynate glycosides
6) Coumarin Glycosides
7) Aldehyde glycosides
8) Steriodal glycoside
9) Phenol glycosides
10) Flavonoid glycosides
11) Bitter and Miscellaneous glycosides

18.  TANNINS
INTRODUCTION:-
Tannins are polyphenolic substances found in many plants product of secondary metabolites. As
the name indicate they posses the property of tan i.e to convert hide and skin into the leather
Detected by qualitatively by tannins test i.e the Goldbeater’s skin test
Present in cell sap and vacuoles.
They act as astringent they have capacity to combine with protein and precipitate them.
 DEFINATION:-
The complex, organic, non-nitrogenous, phenolic substance of higher molecular weight.
• They are used as antiseptics and in gastro-intestinal disease like diarrhoea. They are also
used in leather indust

19. • PROPERTIES
 Tannins are soluble in water, alcohol, dil alkalies, glycerine and acetone but insoluble in
organic solvent such as benzene ether and chloroform,
 They should posses tanning properties
 Tannins with ferric salt gives blue, violet or green colour.
 They have precipitate with alkaloids and have heavy metals therefore they are used as
antidotes in alkaloidal and heavy metal poisoning.
 In aqueous solution tannin produce acidic reaction and have astringent test.

20. • CLASSIFICATION
 Classification based on chemical nature
1. Hydrolysable tannins
2. Condensed tannins
1. Hydrolysable tannins:-
These tannins are hydrolysed by acids or enzymes and produce gallic acid or ellagic acid
Chemically they are esters of sugar usually glucose with one or more trihydroxybenzene
carboxylic acid.
With ferric chloride they produce they produce blue colour hence they are used in
manufactured in ink.
Example:- gallotannin from rhubarb, chestnut, nutgall and clove and ellagitannin from
myrobalam of oak

21. 2. Condensed tannins
They are also called as phlobatannins or proanthocyanidins.
They are related to flavonoids pigments and have the polymeric formula flavone-3-ol.
On the treatment with acids or enzymes these tannins are decomposed into red insoluble
compounds called as phlobaphens.
With ferric chloride they produce green colours.
On heating these tannins produce catechol, therefore they are also called as catechol tannins.
The drugs which contain condensed tannins are cinchona bark, cinnamon bark, pale and black
catechu, cocoa, kola seeds etc.

22.  Pseudotannins-
Pseudotannins are low molecular weight compounds and do not respond to Goldbeater’s skin
test.
Example of pseudotannins are catechins from cocoa and chlorogenic acid from nuxvomica and
coffee.

23.  Extraction and isolation of tannins.
The various type of the methods of extraction depending the source of tannins are employed.
As the tannins are high molecular weight compounds so it becomes difficult to isolate the
tannins in pure form.
Thus the solvent used are the mixture of polar, non polar and semi polar solvent like alcohol,
ether, water, acetone etc.

24. IDENTIFICATION TEST
 Goldbeater’s skin test- The Goldbeater’s skin (membrane prepared from the intestine of
ox) is soaked with HCl. Then it is rinsed with distilled water and is added to the tannin
solution (sample) for 5 minutes. It is washed with distilled water and transferred to 1%
ferrous sulphate solution. A brown black colour on the skin confirms the presence of
tannins.
 Phenazone test- 10ml of aqueous extract of tannins is prepared and 1gm of sodium acid
phosphate is added. Warm it, cool and filter it. To the filtrate 2% phenazone solution is
added. All the tannins present are precipitated.
 Gelatin test- To the solution of tannins add 1% gelatin solution containing 10% sodium
chloride. The precipitate obtain confirms the presence of tannin.

25.  Test with ferric chloride solution- To the solution of tannins add ferric chloride solution.
A blue, black, violet, or green precipitate or colour confirm the presence of tannin.
 Match-Stick test- Dip a match stick in plant extract and dry it. Moisten it with conc. Hcl
and warm near the flame. The wood of match stick turns to pink or red in colour which
confirms the presence of tannins (On heating tannins with conc. Hcl produce
phloroglucinol. Further phloroglucinol react with the lignin of wood and produce pink
colour