Acacia: Source, Production, Chemical Constituents, Chemical Tests, Uses and Adulterants

Source, Method of Production, Chemical Constituents, Chemical Tests, Uses and Adulterants of Acacia

Objectives

• At the end of this lecture, student will be able to:

- Discuss the pharmacognostical aspects of acacia

Acacia

Synonym: Gum acacia, gum arabica

Source: Dried gummy exudation from the stems and branches of Acacia Senegal, Acacia Arabica and other species of Acacia

Family: Leguminosae

Geographical distribution

• India, Srilanka, Sudan, Morocco and Africa

• Punjab, Rajasthan and Western Ghats

Acacia - Method of preparation/Collection

• Trees are kept properly pruned

• Seven year old trees - without injuring the cambium

• Twist the axe and pull it back

• Strip of bark is removed

• Formation of gum - first in phloem and cambium

• Tears near the lower end of the wound

• Gum collected

• Translusent tears, exposure to sun, develops cracks, friable

Description

• Tears - cream brown to red, Powders are light brown

• Odourless

• Bland and mucilaginous

• Varying sizes

Chemical constituents

• Arabin - salt of calcium, magnesium and potassium salts of Arabic acid

• Arabic acid - L rhamnose, D galactose and L arabinose and aldobionic acid

• Enzymes - Oxidase and peroxidase

Chemical tests

• Sample + cold water: soluble

• Sample + alcohol: insoluble

• Hot aqueous solution - with blue litmus:  Blue turns red

• Fehlings test: Red precipitate

• With lead sub acetate solution: white precipitate

• With lead acetate solution: no white precipitate

• With ferric chloride solution: no bluish black colour

• With iodine solution: no blue colour

• Sample + ruthenium red solution - Transparent granules

• Sample + Alcoholic benzidine and hydrogen peroxide - Blue colour (Oxidase)

• Demulcent, Emulsifying and suspending agent

Substitutes and adulterants

• A.arabica and A. modesta

• A.gummifera

• A.dealbata, A. pycnantha

• A. horrida

• East African gums dextro rotatory

Summary

• Acacia is the dried gummy exudation from Acaica arabica with arabin content. Being a gum it gives negative with ruthenium red and can be confirmed by enzyme oxidase test