ASTRINGENTS
CATECHU
BLACK CATECHU
 |
| acacia catechu,astringent |
Synonyms -: Catechu Nigrum, Cutch.
Source -:
Black catechu is a dried extract
prepared from the heart wood of Acacia catechu Wild.
Family -: Leguminoseae
Geographical
occurrence -:
The plant is a tree of medium size. It grows in India and Burma.
Preparation
-:
1. The trees arc felled the heart wood
cut into pieces and boiled with water in earthen pots.
2. The decoction is evaporated in an
iron vessel to form a thick syrup. Because of iron in the vessel, catechu
becomes black le colour.
3. It is then poured on leaves or
paper and allowed to solidify. Then it is cut into pieces and marketed.
Characters
-:
1. Black catechu occurs in the form of
black or dark brown irregular masses or cubes.
2. The outer surface is glossy and
porous.
3. Fracture is brittle and it breaks
into a powdery mass.
4. It has no odour. But taste is
bitter initially, then tums sweet and finally astringent.
Constituents
-:
1. Tannins -: They are catechins and
catechu tannic acid.
2. Flavinoids : They are quercetin and
its derivatives.
Identification
tests -:
1.
Black catechu is completely soluble in alcohol and hot water.
2.
Addition of lime water to the aqueous extract produces a brown colour. This on
standing produces a red precipitate.
3.
Aqueous solution of black catechu produces a dark green colour with ferric
chloride solution.
4.
It produces a pink or red colour with vanillin hydrochloric acid
5.
The tip of a match stick is smeared with a paste of black catechu, after
dipping in concentrated hydrochloric acid; it is warmed near a flame. A purple
colour is produced.
Gambir
fluorescine test -:
Powdered drug is boiled with alcohol and filtered.
To the filtrate, sodium hydroxide solution is added followed by petroleum
ether. The petroleum layer shows a green fluorscence only for pale catechu.
This can distinguish from black catechu.
Uses -:
1. Astringent in diarrhoea.
2. For cleaning the mouth and gums,
3. In dyeing and tanning industry.
