Source, Method of Production, Chemical Constituents, Chemical Tests, Uses and Adulterants of Tragacanth
Objectives
At the end of this
lecture, student will be able to:
• Discuss the pharmacognostical aspects of
- Tragacanth
Tragacanth
Synonym: Tragacantha,
gum tragacanth
Source: Dried
gummy exudation obtained by incising the stems and branches of Astragalus
gummifer and other species of Astragalus
Family: Leguminosae
Geographical
distribution: Iran, Greece, Turkey, Iraq, Syria and India
Tragacanth - Method
of preparation/collection
• Stems and branches incised, gum exudes and dried
• Form of incision: Vertical slits- ribbon shaped pieces,
punctures-tears
• Transformation of the cell walls of the pith and medullary
rays
• First tapping - white, subsequent tapping - yellow
coloured gum
Description
• White or pale yellowish or brown
• Odorless
• Mucilagenous
• Thin, flattened ribbon or powder
Chemical constituents
• Tragacanthin
• Bassorin- Viscosity – 60% - (minimum 3.75 % of methoxy
groups)
- Tragacanthic
acid - galacturonic acid, galactose, xylose and fucose
- Neutral
polysaccharide on hydrolysis yields arabinose and galactose
- Glycoside of
sterol derivative
Chemical tests
• Sample + water: Insoluble
• Fehlings test: Red precipitate
• Sample + ruthenium red: NO pink mucilage
• With N/50 Iodine solution: Green
colour
• With alcoholic potassium hydroxide solution: Canary yellow
colour
• With lead acetate solution: White precipitate
• With lead sub acetate solution: White precipitate
Uses
• Suspending, emulsifying agent
• Binding agents in tablets
• Demulcent
• Emollient in cosmetics
• Thickening agent
Substitutes
• Indian tragacanth (sterculia gum) - Sterculia urens
(sterculiaceae)
• Katira gum - Cochlospermum gossipium (Cochlospermaceae)
• Vermicelli tragacanth / hog gum - Astragalus cylleneus
Summary
• Tragacanth is from Astragalus gummifer with tragacanthin and bassorin content
Posts
0 Comments