Page 175 - Pharmacognosy-II (06-PG 303)

Gums
2.Gum Tragacanth
Astragalus, Bony milk

It is the air-dried gummy exudate flowing naturally or obtained by incision
from trunk and branches of Astragalus gummifer f. Leguminoseae (fabaceae).

Constituents:
• Water soluble fraction: Tragacanthin (contain NO methoxyl
groups).
• Water insoluble fraction: Bassorin (contain about 5% methoxyl
groups).

Collection and preparation
• Wide incision are made in the trunk base and woody pieces are
introduced into the injury to accelerate gum exudation.
• White sticky secretion exudates due to conversion of medullary
rays and pith into gum.
• The mode of formation of tragacanth is completely DIFFERENT
from that of acacia: In Tragacanth the gum exudes
IMMEDIATELY after injury, therefore being PRE-FORMED
in the plant, while acacia is slowly produced after injury.
• Absorb water exerting pressure and hence expelled.
• Contain starch.

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