Page 58 - final Practical handout PG 303-Cogno-2- 2024-2025

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

Borax +ve -ve

Fehling's test: aqueous solution of gum arabic or gum tragacanth + 0.5 ml HCl, heat

(W.B. 30 min.), neutralize by NaOH and add Fehling's solution, warm, gives red ppt.

Oxidase enzyme test: aqueous solution of gum arabic + 5 drops H₂O₂ and 5 drops

benzidine, shake, allow to stand, a deep blue color is slowly formed.

Dried extracts

Prepared by evaporating the aqueous decoction of parts of certain plants or animals e.g.
agar, gelatin.

Agar-Agar ‫اجار‬ Gelatin ‫جيلاتين‬

* Shape: strips, flattened sticks, diatoms * Shape: pale yellowish translucent sheets
(species of Arachnoidiscus), granulated or granular powder.
powder.

Specific chemical tests: Specific chemical tests:

✓ Purple color with dil. Iodine solution. ✓ White ppt. with tannic acid.
✓ Deep red with ruthenium red. ✓ Brick red with millon's reagnt.
✓ BaCl₂ test: white ppt. with

sulphonated polysaccharide

Agaropectin

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