Page 25 - phytochemistry I - PharmD Clinical

 Gum Tragacanth is the air-dried gummy exudates obtained by incision from the
trunk and branches of Astragalus gummifer and certain other species of Astragalus
grown In Western Asia (Leguminosae).

Chemical composition:
 Tragacanth consists of a water-soluble fraction known as tragacanthin
and a water-insoluble fraction known as bassorin, Tragacanthin contain
no methoxyl groups but bassorin contained about 5.38% methoxyl
groups.

Uses:
1- Suspending agent for insoluble powders.
2- As a binding agent in pills and tablets.
3- Emulsifying agent for oils and resins. Tragacanth is the most resistant of the
hydrocolloids to acid hydrolysis and is preferred for use in highly acidic conditions.
4- In cosmetics as an emollient and demulcent.

Guar gum

Occurrence:
 Guar gum is obtained from the ground endosperm of the Indian
leguminous plant Cyamopsis tetragonolobus and has recently received
some attention as a possible oral hypoglycaemic drug.

Chemical composition:
 The principal constituent of the gum is galactomannan, which readily
forms a viscous gel with water.

Uses:
1- It can produce changes in gastric emptying and in the gastrointestinal transition

time, which can delay absorption of sugars and oligosaccharides from the gut.
2- It lowers cholesterol levels, possibly by binding bile salts in the gut.

Agar

Occurrence:
 Agar is the dried colloidal concentrate from a decoction of various red
algae

۲٤