Question

Chemical test for identification of cardiac glycosides

Answer 1

Chemical tests for cardiac glycosides:

1. Raymond’s test:

To the drug, add a few ml of 50% ethanol and 0.1 ml of 1 % solution of m- dinitrobenzene in ethanol. To this solution, add 2-3 drops of 20% sodium hydroxide solution. Violet colours appears, this is due to presence of active methylene group.

2. Legal test:

To the drug, add few ml of pyridine and 2drops of nitroprusside and a drop of 20% sodium hydroxide solution. A deep red colour is produced.

3. Killer killiani test:

Glycoside is dissolved in a mixture of 1 % ferric sulphate solution in (5%) glacial acetic acid. Add one or two drop of concentrated sulphuric acid. A blue colour develops due to the presence of deoxy sugar.

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4. Xanthydrol test:

The crude is heated with 0.1 to 5% solution of Xanthydrol in glacial acetic acid containing 1% hydrochloric acid. A red colour is produced due to the presence of 2-deoxysugar.

5. Baljet test:

Take a piece of lamina or thick section of the leaf and add sodium picrate reagent. If glycoside is present yellow to orange colour will be seen.

6. Kedde test:

A solution of glycosides is treated with a small amount of Kedde reagent (Mix equal volumes of a 2% solution of 3, 5 dinitrobenzoic acid in menthol and a 7.5% aqueous solution of KOH). Development of a blue or violet colour that faded out in1 to 2 hrs shows it presence of cardinoloids.

7. Antimony trichloride test:

To a solution of glycoside add a solution of antimony trichloride and trichloroacetic acid, and then heat the mixture. Appearance of blue or violet colour show presence of cardenolides and bufanolides