1. Pale catechu, black catechu, and pterocarpus are tannin-containing drugs used as astringents. 2. Pale catechu is prepared from leaves and shoots of Uncaria gambier, black catechu from heartwood of Acacia catechu, and pterocarpus from dried juice of Pterocarpus marsupium tree. 3. They contain tannins like catechins and catechu tannic acid which give them astringent properties useful for treating diarrhea and other conditions.

1. TANNIN CONTAINING DRUGS:
PALE CATECHU
BLACK CATECHU
PTEROCARPUS

2. PALE CATECHU
Synonyms – Pale catechu, gambier
Biological source – It consists of the dried
aqueous extract prepared from the leaves
and shoots of Uncaria gambier
Family -Rubiaceae

3. Cultivation, Collection and Preparation
•Propagated by sowing seeds in damp soil.
•Seedlings are transplanted to open fields.
•Harvesting is done when plant reaches 2 m height.
•Plant gives drugs upto 20 years
•Leaves and young shoots are boiled in pots called cauldron, made of
wood with iron bottom for 3 hours.
•The decoction obtained is concentrated till it becomes yellowish
green paste like mass.
•It is moulded in cubes and dries.
Description: Reddish brown cuboidal mass. Friable in nature. It I
odorless with astringent taste.

4. Chemical constituents
Condensed tannins like catechins and
catechu tannic acid.
It contains flavonoid like quercetin and
fluorescent substances Gambier fluorescein.
It also contains catechu- red, pyrogallol, fixed oil
and waxes.

5. Uses –
Used as an astringent
Used in the treatmentof diarrhoea
Used in the preparationof lozenges

6. BLACK CATECHU
Biological source –
It consists of the dried aqueous extract prepared
from heart wood of Acacia catechu and Acacia
chundra
Family- Leguminosae
Synonyms: Kattha, Cutch, Khadir catechu

7. Preparation
•The heart wood is separated and boiled in earthen vessels till complete
extraction.
•It is cooled to a semisolid mass.
•Upon cooling, the less soluble fraction separates out which is removed
as Kattha and semisolid mass as Cutch.
•It is transferred to rectangular pits, at the bottom of which, sand and
clay are placed.
•It is kept for several days till the cutch part is absorbed by sand and clay
and the solid mass is taken out and moulded into blocks.

8. Chemical constituents –
It contains 10 % Acacatechin or Acacaia Catechin. This gets
oxidized to give Catechutannic acid in presence of water
. Other
constituents are Catechu Red, Quercetin and gums.
Uses –
Used as an astringent, used indiarrhoea
Used as a cooling and digestiveagent

9. Chemical Tests For Pale 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 )

10. 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.

11. 3. Vanillin – Hydrochloric acid test–
Test solution and few drops of Vanillin –
Hydrochloric acid reagent – A red or pink is
formed due the formation ofphloroglucinol.
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– greenresidue

12. Chemical Tests For Black Catechu
•It gives pink or red color with Vanillin and HCl due to presence of
Catechin.
•Catechin when treated with HCl produces Phloroglucinol which
burns with lignin to give purple color.
•Aqueous extract of black catechu treated with lime water gives
brown color which turns to red ppt upon standing.
•Dilute solution of back catechu added with ferric ammonium sulfate
gives green color which turns to purple upon addition of sodium
hydroxide.

13. Pterocarpus
Synonyms: Bijasal. Indian Kino Tree, Malabar Kino
Biological Source: It consists of the dried juice of
whole plant of Pterocarpus marsupium obtained
by making vertical incisions in the stem bark,
belonging to family Leguminosae.
Geographical Source: Gujarat, MP, UP, Bihar,
Odisha, Kerala, West Bengal and Assam.

14. Macroscopy
Color – Ruby Red
Odor - Odorless
Taste – Astringent
Shape – angular
CHEMICAL CONSTITUENTS
70 – 80 % Kinotannic acid, Kino Red, K – Pyrocatechin,
resins and gallic acid. By the action oxidase enzyme, an
insoluble phlobaphene called Kinoin is produced.

15. CHEMICAL TESTS
Solution of drug treated with ferrous sulfate gives
green color.
Solution of drug with potassium hydroxide gives
violet color.
It gives a precipitate with mineral acid.
USES
Astringent, treatment of diarrhea, diabetes,
haemorrhage, toothache.
Dyeing, tanning and printing industry.