Page 57 - final Practical handout PG 303-Cogno-2- 2024-2025

Clinical Pharm D Level 2 Pharmacognosy-2 (PG 303)

Gums

* Chemically: Ca, K, Mg salts of polyuronides; when hydrolyzed give sugar acids
(uronic acids), and mixtures of sugars.

* Artificial gum (Dextrin): obtained from starch by enzymatic degradation or incomplete
acid hydrolysis, it is used as adhesive material as gum. It can be differentiated from natural
gum by optical activity as artificial gum (dextrin) is strongly dextrorotatory while natural
gum is slightly levorotatory.

Item Gum acacia Gum tragacanth
‫صمغ الكثيرة‬
(Gum Arabic)
‫الصمغ العربي‬ Europe and central asia

Natural habitat Africa

Shape Rounded or ovoid tears. Ribbon-shaped flakes or
occasionally in straight or
Texture Brittle spirally twisted linear pieces.
Taste Gummy Hard

Mucilaginous

Chemical Gum acacia Gum tragacanth
Test (Gum Arabic)
-ve
Oxidaze +ve (deep blue) Scattered blue spots
enzyme Canary yellow after heating
Iodine -ve (yellowish brown) Flocculant white ppt
NaOH -ve
Lead acetate -ve -ve

Lead Flocculant white ppt
subacetae

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