Page 129 - pharmacognosy2- pharmD- e-book

GUMS

They are heterogeneous polysaccharides formed of condensation product off
sugars (pentoses, hexoses but no glucose) and uronic acid.
Plants produce them as a protective after injury or unfavorable condition. They are
formed from the cell walls by the action of enzymes.
Gums are natural polymers, capable of causing a large viscosity increase in solution,
even at small concentration; chemically they are condensation products of sugars
(except glucose) and uronic acids.
They can be classified according to the source into:

– Exudate gum:
Natural protecting agent obtained by injury of trees ex.Gum Acacia, gum
Tragacanth.

– Seed gum:
Ex. Guar gum.

– Artificial gum.
According to solubility in water:

– Soluble in water
– Gums which swells into jelly-like mass. According
to the charge:
- Non-ionic seed polysaccharides

Guar, Locust Bean (Carob) Tamarind
- Anionic exudate polysaccharides :

Arabic, Karaya, Tragacanth Gums are usually insoluble in alcohol.
Stability of Gums:Most gums are resistant to microbial degradation

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