Page 76 - Phytochemistry -1 (PG404) / Clinical Pharmacy 2nd level students ( 2019 )

Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

PRELIMINARY PHYTOCHEMICAL SCREENING

OF UNKNOWN DRUGS

Subject the powdered drug under investigation to the following tests

1. Micro-sublimation

Subject about 1 g of the powdered drug to careful microsublimation.

Examine the sublimate under the microscope, add one drop of each of

sulfuric acid, potassium hydroxide and Kedde's reagents separately to the

sublimate and observe under the microscope.

2. Test for carbohydrates and/or glycosides

Mix about 10 g of the powdered material with about 60 ml of 25% ethyl

alcohol containing 2% tartaric acid. Reflux the whole mixture on a water

bath for 12 hours, filter and wash the marc several times with hot 95%
ethyl alcohol. Evaporate the combined filtrate and washings to dryness

under reduced pressure at 40 to 50'C and extract the residue with four
portions, 5 ml each, of hot distilled water. To 5 ml of the aqueous extract,

add about o.5 ml of freshly prepar9d alcoholic solution of -naphthol and
pour sulfuric acid carefully on the side of the test tube to form a separate

layer. The formation of a violet zone at the junction of the two layers

indicates the presence of carbohydrates and/or glycosides.

3. Test for cardenolides

Boil about 10 g of the powdered material with 100 ml of distilled water

for 10 minutes and then filter. Shake about 50 ml of the clear filtrate with

50 ml of chloroform for few minutes, add 25 ml of ether followed by 25

ml of ethyl alcohol and shake the whole mixture again. Separate the

chloroform-ether extract and evaporate to dryness. Dissolve the residue in

5 ml of ethyl alcohol and then to 1 ml of the alcoholic solution, add 1 ml

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