This presentation meant for second year B.pharmacy students for the subject of Pharmacognosy and Phytochemistry It contains Definition, classification, properties and test for identification of Tannins

1. Tannins
Definition, classification, properties and test for identification
PRESENTED BY:
MR. PRITAM VIJAY JUVATKAR
ASSISTANT PROFESSOR
pvjuvatkar@rediffmail.com, +91 9987779536
KONKAN GYANPEETH RAHUL DHARKAR COLLEGE OF PHARMACY AND RESEARCH INSTITUTE,
KARJAT
UNIVERSITY OF MUMBAI

2. Pritam Vijay Juvatkar 9987779536 Tannin 2
• Definition
 These secondary metabolites mixture of complex organic substances in which polyphenols are present,
generally with o-dihydroxy or o-trihydroxy groups on a phenyl ring, astringent substances, Capacity to
combine with tissue proteins and precipitate them, Mild antiseptics.
• Physical & Chemical Properties of Tannin
 Fairly high molecular weight, colloidal solutions, Non-crystalline substances and acidic in nature
 soluble in alcohol, glycerine, dilute alkalies, but practically insoluble in organic solvents except
acetone
 Solution of tannin precipitates gelatin, and alkaloids.
 Tannins are precipitated by salts of copper, tin, and lead.
 They are precipitated by strong potassium dichromate solution or chromic acid solution.
 Ferric chloride gives bluish-black or brownish- green colour potassium ferri cyanide with ammonia
gives deep red colour.
Tannin

3. Pritam Vijay Juvatkar 9987779536 Tannin 3
• Classification of Tannins
 The tannins are broadly classified into three groups based on complexity of their chemical nature
and according to their behavior on dry distillation.
 Hydrolysable Tannins
 Condensed Tannins
 Pseudotannins

4. Pritam Vijay Juvatkar 9987779536 Tannin 4
Classification of Tannins-: Hydrolysable tannins
 Tannins are hydrolysed by acids or enzymes gives gallic acid or ellagic acid.
 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
 Myrobalan
 Bahera
 Arjuna
 Amla
 Galltannin in nutgall,
 Rhubarb,
 Clove and
 Chestnut;
 Ellagitannin from oak,
 Myrobalans
 Pomegranate bark.
O
O
O
O
OH
OH
O
H
O
H
Gallic acid
Ellagic acid
Pyrogallal

5. Pritam Vijay Juvatkar 9987779536 Tannin 5
Classification of Tannins-: Condensed tannins
 They are much resistant to hydrolysis
 They are related to flavonoid pigments, phlobatannins or proanthocyanidins
 On dry distillation they yield catechol
 Tannins with ferric chloride produce brownish-green colour
 Unlike the hydrolysable tannins, on treatment with enzymes or mineral acids, they are polymerized
or decomposed into red coloured substances called phlobaphenes
 They are formed via derivatives of flavones, like catechin or flavan-4-ol or flavan-3, 4-diols

6. Pritam Vijay Juvatkar 9987779536 Tannin 6
Classification of Tannins-: Condensed tannins
 They are distributed in different parts of plants,
 The green tea and hamamelis leaves;
 Cinchona, cinnamon and
 Ashoka and Wild cherry bark;
 Male fern rhizome;
 Cocoa, cola and areca seeds;
 Pale and black catechu
Glucogallin Catechin
Catechol
Classification of Tannins-: Pseudotannins
 They do not obey to goldbeater's skin test and are low molecular weight compounds.
 Examples: Chlorogenic acid in coffee and nuxvomica, ipecacuanhic acid in ipecacuanha and catechins in cocoa

7. Pritam Vijay Juvatkar 9987779536 Tannin 7
Chemical Test of Tannin :Goldbeater's skin test
Untanned fresh skin of an animal intestine of ox Treated
with hydrochloric acid
.
putting in ferrous sulphate solution.
placed in tannin solution for 5 minutes.
Washing with distilled water
A brown or black colour is
developed on the skin due to tannin.
Rinsed with distilled water

8. Thank You
PRESENTED BY:
MR. PRITAM VIJAY JUVATKAR
ASSISTANT PROFESSOR
pvjuvatkar@rediffmail.com, +91 9987779536
KONKAN GYANPEETH RAHUL DHARKAR COLLEGE OF PHARMACY AND RESEARCH INSTITUTE,
KARJAT
UNIVERSITY OF MUMBAI

9. Disclosure
PRESENTED BY:
MR. PRITAM VIJAY JUVATKAR
ASSISTANT PROFESSOR
pvjuvatkar@rediffmail.com, +91 9987779536
KONKAN GYANPEETH RAHUL DHARKAR COLLEGE OF PHARMACY AND RESEARCH INSTITUTE,
KARJAT
UNIVERSITY OF MUMBAI
This Presentation is meant for Study Notes for B.Pharm Students only. Please do
not take as a reference for treatment for an ailments or other usage