Pharmacognosy of Indian Gum

Devesh

Devesh


Synonyms

Gum acacia, Gum Arabic, Acacia

Biological Source

Indian Gum is dried gummy exudation obtained from the stem and branches of Acacia Arabic wild, belonging to family Leguminosae.

Geographical sources

The plant is found in India, Sri Lanka, Sudan, Morocco and Africa. In India, it occurs in Punjab, Rajasthan and Western ghats. About 85% of world supply of gun acacia is from Sudan.

Cultivation & Collection

It is a common member of dry monsoon forests of India. It is an evergreen tree with short trunk. It is not cultivated on commercial scale. Gum is collected from wild grown plants, made free of bark and foreign organic matter, dried in sun, which also results-in partial bleaching of gum

Description

Colour: Tear are cream-brown to red in colour, while powder is light brown in colour.

Odour: Odourless.

Taste: Bland & Mucilaginous.

Size & Shape: Irregular brown tears of varying size.

Extra Features

The tears are glossy & marked with minute fissures and are brittle in nature. The pieces of broken tears are with angular fragments and glistering surfaces, breaking with difficulty, and with conchoidal fracture.

Solubility

It is soluble in water, the water solubility is viscous and acidic. It is insoluble in alcohol.

Standards

It should contain not more than 15% of moisture & 5% of ash Indian Gum should not contain tannin, starch & dextrin.

Chemical Constituents

It consist principally of Arabin, which is a complex mixture of calcium, magnesium & potassium salts of Arabic acid. Arabic acid on hydrolysis gives L-arabinose, L-rhamnose, D-galactose, & D-glucuronic acid. It also contains an enzyme Oxidase, & Peroxidase.

Identification

  1. Solution of lead subacetate gelatinises the aqueous solution of indian gum.
  2. It does not produce a pink colour with the solution of euthenium red.
  3. On addition of solutions of hydrogen peroxide & benzidine in alccohol to aqueous solution of gum, blue colour is produced due to oxidase enzyme.

Uses

Acacia is demulcent. It is also administered intravenously in haemolysis. In the form of mucilage, it is used as a suspending agent, specifically in mixture with resinous substance. Acacia is a good emulsifying agent for fixed oils, volatile oils and also for liquid parafinn. It is good bindinging agents and is used in the preparation of lozengers, pastilles and compressed tablets. It is a gum of choice, as it compatible with other plant hydrocolloids, as well as, starches and carbohydrates. In combination with gelatin, it is used to form coacervates for microencapsulation of drugs.

Test for purity of Indian Acacia

  1. Dilute 1 ml of the solution of gum with 10 ml of water and keep for few hours. No sedimentation should take place.
  2. To 1 ml of solution, add 4ml of water, boil, cool and add 2 drop of N/10 iodine. Brown colour indicates presence of dextrine, whereas blue colour is due to starch. This test should be negative with authentic drug.
  3. To the gum acacia solution, add a drop of hydrogen peroxide and tincture of guaiacum – blue colour is produced.
  4. With few drops of 0.1% ferric chloride to 1 ml. of the solution, blue or black colour (due to tannins) is produced.

Substitutes & adulterants

B.P variety consists of Gum obtained from Acacia Senegal / Wild ,(Leguminosae) a plant of african origin and grown in Africa. The tears are rounded or ovoid and about 5-40 mm in diameter. Tears are yellowish white in colour. It can be used as-a substitute to indian gum.

Indian gum is adultrated with Gum ghatti, obtained from Anogeissus Latifolia (Combretacea), which is distinguished from the genuine drug by the following characters. It’s outer surface is dull and whithout fissures. It shows very slight precipitate with lead subacetate solution and it’s aqueous solution is highly viscous. Starch, Tragacanth, dextrin & Sterculia gum are the other adultrants of acacia.

Storage

Acacia or Powdered acacia should be stored in cool dry place in air-tight container.