EXPERIMENT NO 01. ANALYSIS OF CRUDE DRUGS BY CHEMICAL TEST (SAMPLE - TRAGACANTH) S.Y B. PHARM SEM - IV PRACTICAL

 

SECOND YEAR B. PHARM PRACTICALS

IV SEMESTER (II-B.PHARM)

PHARMACOGNOSY AND PHYTOCHEMISTRY -I

PRACTICAL

EPERIMENT NO. 01

ANALYSIS OF CRUDE DRUGS BY CHEMICAL TEST

AIM: TO IDENTIFY THE GIVEN CRUDE DRUG SAMPLE BY CHEMICAL TEST

REFERENCE:

1.      Kokate CK. Practical Pharmacognosy, 4 edition, Vallabh  Prakashan. Delhi; 1994: 98

2.    Dr. K. R. Khandelwal. Practical Pharmacognosy, 22^nd edition, Nirali prakashan, April 2012, Page No. 27.19.

REQUIREMENTS:

APPARATUS: Test tube, Test tube stands, Test tube holders, Pipette, Measuring cylinder, Glass slide, Microscope.

CHEMICALS: Hydrochloric acid,  Sodium hydroxide solution,  Fehling’s solution,  Barium chloride solution, Lead acetate, Ruthenium red, Iodine Caustic potash.

TRAGACANTH: (Background)

Tragacanth is the dried gummy exudation from the stem of Astragalusgummifer, Labillardiere and other species of Astragalus (Fam. Leguminosae). It occurs in flat or curved ribbon shaped flakes. Odourless, almost tasteless, white or pale yellowish-white, somewhat translucent, horny; fracture short.

Tragacanth is an unorganized drugs, as the name suggests, are drugs that show no definite cellular structure. These are derived from plant, animal or mineral sources by some process of extraction and followed by purification if necessary. Unorganized drugs are fairly homogenous and may be solids, semisolids or liquids. These may be differentiated by observing the solubility in alcohol and then applying other physical and chemical standards.

Synonyms and Regional name: Gum Tragacanth, Hin.-Anjira.

Biological source: Tragacanth is dried gummy exudation obtained by incision from the stem & branches of Astragalus gummifer Labill & other species of Astragalus. Family: Leguminosae.

MACROSCOPICAL & PHYSICAL CHARECTERSTICS:

COLOUR: White or pale yellowish

ODOUR: Odourless

TASTE: Tasteless

SHAPE: Thin flattered ribbon like flakes.

SIZE: Flakes are 25*12*2mm

SOLUBILITY: Partly soluble in water, swells, insoluble in alcohol.

ETRA FEATURES: The gum is horny translucent, transverse with longitudinal ridges. Fracture is a short.

CHEMICAL CONSTITUENTS: It contains a complex polysaccharide carbohydrate.

a. Water-soluble Tragacanthin (30-40%)

b. Water insoluble Bassorin (60-70%)

Tragacanth in turn consists of (a) tragacanthic acid + (galacturonic acid + xylose + fructose + galactose) and (b) Arabinogalactan + (arabinose + galactose + galacturonic + Rhamnose in small quantities). It is also contains 3% starch and cellulose.

USES:

1. It is used as a demulcent (soothing).

2. Suspending agent.

3. Binding agent.

4. Emulsifying agent.

5. Laxative.

6. It is used in adhesive

7. In textile industry.

CHEMICAL TEST:

1. To 4ml of 0.5%w/v solution add 0.5ml of HCl and heat for 30minutes on water bath. Divide the hydrolyzed product in 2 parts

a)  1^st part=Add 1.5ml of NaOH solution to neutralize and add Fehling’s solution A and B in equal quantities(mixed before) and warm over water bath.

b)  2^nd part= Add barium chloride solution

O   OBSERVATION:                                       

 1^st part = Red ppt of cuprous oxide    

 2^nd part = No ppt                                 

INFERENCE:

Reducing sugars are present

Distinction from agar

2. Tragacanth solution (boil)+ 10% aq. Ferric chloride solution

OBSERVATION:   Deep yellow ppt

INFERENCE: Tragacanth may be present.

3. Tragacanth + conc. Ammonium hydroxide + precipitated copper oxide.

OBSERVATION: Stingy ppt

INFERENCE: Tragacanth may be present

4. To 0.5% w/v solution add 20%w/v solution of lead acetate.

OBSERVATION: Heavy white flocculent ppt

INFERENCE: Distinction from acacia.

5. Mount a small quantity of powder in ruthenium red and examine microscopically.

OBSERVATION: Particles do not acquire pink colour

INFERENCE: Distinction from Indian tragacanth and agar

6. To 0.1gm of powder add N/50 iodine.

OBSERVATION: The mixture acquired greenish colour

INFERENCE: Distinction from acacia and agar

7. If powder is warmed with 5% alcoholic KOH solution.

OBSERVATION: Canary yellow colour

INFERENCE: Tragacanth confirmed

RESULT: From the above morphological characters and chemical tests the given crude drug is identified as Tragacanth.