ASTRINGENTS | CATECHU | BLACK CATECHU

  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.