CATECHU

Synonyms – Pale catechu, gambier,

kattha

Biological source – It consists of the dried

aqueous extract prepared from the

leaves of Uncaria gambier

Family - Rubiaceae

Chemical constituents –

It contains tannins like catechins and

catechu tannic acid

It contains flavonoids like quercetin and

fluorescent substances Gambier

fluorescein.

It also contains catechu- red, pyrogallol,

fixed oil and waxes

Uses –

Used as an astringent

Used in the treatment of diarrhoea

Used in the preparation of lozenges

BLACK CATECHU

Biological source –

It consists of the dried aqueous extract

prepared from heart wood of Acacia

catechu and Acacia chundra

Family - Leguminosae

Chemical constituents –

It contains tannins like catechins and

catechu tannic acid

It contains flavonoids like quercetin.

Others like Catechu- red and gum

Uses –

Used as an astringent, used in diarrhoea

Used as a cooling and digestive agent

CHEMICAL TESTS FOR CATECHU

1. Gambir Fluorescin test-

Alcoholic extract of drug, few drops of

sodium hydroxide mix and add

petroleum ether, shake and kept aside

for few minutes – petroleum ether layer

shows green fluorescence ( + ve for pale

catechu due Gambir Fluorescin )

2. Match stick test ( Catechins test) –

A match stick is dipped in aqueous plant

extract , dried near burner and

moistened with Hcl. On warming near

flame , the match stick wood turns pink

or red due to the formation of

phloroglucinol.

3. Vanillin – Hydrochloric acid test –

Test solution and few drops of Vanillin –

Hydrochloric acid reagent – A red or pink is

formed due the formation of phloroglucinol.

4. Chlorophyll test -

Powdered drug is heated with chloroform on

a water bath for 1-2 minutes .The organic

layer is filtered in a china dish and

evaporated on the water bath– green

residue

TANNIC ACID

Biological source –

It is obtained from the nutgalls. Galls are

vegetable outgrowths found on the young

twigs of Quercus infectoria

Family - Fagaceae

Tannic acid is a hydrolysable tannin and

yields Gallic acid and glucose on hydrolysis

Uses –

Used as an astringent

Used externally in the treatment of burns

Used as an antidote for alkaloid

poisoning

NUTGALL Synonym – Turkey galls

Biological source – Galls are the pathological

outgrowths formed on the twigs of the oak

tree Quercus infectoria

Family - Fagaceae

Chemical constituents – 40-60% of tannic

acid

Uses- Used as an astringent, used in the

manufacture of tannic acid

QUESTIONS –

Define tannins and explain various methods of estimation of

tannins.10 M

Write a note on general properties and method of isolation of

tannins. 10M

Write the source, active constituents and uses of Catechu and

Nutgall.5M

Explain the different types of tannins with examples.5M

Write a note on Goldbeaters’ test and its significances.5M

Write a note on estimation of Hydrolysable tannins.5M

Give the chemical tests for the identification of Catechu

and Tannic acid.5M

Give an account of Catechu.5M

What are tannins? Give general chemical tests to identify

them.5M

Define Tannins. How will you differentiate True tannins

from pseudo tannins ? 5M

Write in brief about Nut gall. 2M

Chemical tests for the identification of tannins.2M

What is tannic acid and give its uses.2M

Gambir- Flurorescin test and its significances.2M

Define Pseudo- tannins and give examples. 2M