(a) Liebermann’s test: 2 ml of the organic extract was dissolved in 2
ml of chloroform and 2 ml of acetic acid was added and the solution
cooled well in ice. Sulphuric acid was then added carefully. A colour
change from violet to blue to green indicates the presence of a
steroidal nucleus (that is, a glycone portion of glycoside).
(b) Salkowski’s test: 2 ml of each extract was dissolved in 2 ml of
chloroform. 2 ml of sulphuric acid was added carefully and shaken
gently. A reddish brown colour indicates the presence of a steriodal
ring (that is, a glycone portion of glycoside).
(c) Keller-Kiliani test: 2 ml of each extract was dissolved in 2 ml of
glacial acetic acid containing one drop of FeCl3 solution. The
mixture was then poured into a test tube containing 1 ml of
concentrated H2SO4. A brown ring at the interphase indicates the
presence of a deoxy sugar, characteristic of cardenolides.