Page 357 - Pharmacognosy 2 PG303

Constituents Pharmacognosy-2 (PG303)
Uses
It is a galactan (polysaccharide) formed of 1,3
D-galactose which is partially Sulphated.
• Suspending agent
• Bulk laxative
• As gel in bacteriological
culture media and plant tissue
culture
• For making emulsions
• For thickening ice cream

Tests for identity: Stiff jelly

1-Cooling of hot Boil agar with HCl → set aside
solution 10min→decant→examine the residue
microscopically
2-Microscopical
examination

3- Tannic acid No precipitate is formed bath
test ppt
Agar +H2O→ boil + HCl and
4- Barium chloride test heat for 30 min. on water-
+1 mL BaCl2 T.S.→ white
5- Millon’s reagent
No ppt

6- Ruthenium Particles-stained deep red
red test No Ammonia gas evolved

7- Soda lime test