khelin

Extract anthraquinone

place 0.5gm of powdered drug in a beaker and add 50 ml of water

Boil gently for 15 minutes , cool and centrifuge.

place the filtrate in a separatory funnel and extract by shaking with two quantities of ( 2 × 30 ml ) chloroform


combine the chloroform
extract and then concentrate
to about 1ml
( fraction B(.free aglycone)

the aqueous extract will be divided into two parts, one will be placed in a small flask and evaporate carefully almost to dryness on a rotatory evaporator. ( fraction A (glycoside))



the other part placed in a 250 round – bottomed flask and adding to it 3.5 ml of ferric chloride solution ( 60 % w/v). Reflux for 20 minutes and add 2 ml of conc. HCl acid


continue heating for further 20 minutes , shaking the flask occasionally to dissolve as much as possible of the precipitate , and allow cooling.


place the hydrolysate in a separatory funnel and extract with two quantities of ( 2 × 30 ml ) chloroform.


concentrate the bulked chloroform extracts to about 3 ml. ( fraction C(aglycone) )


Chemical tests of anthraquinone:

Bromine test : is used to identify anthraquinone glycosides in general. Its procedure is : to two ml of the extract add an equal volume or an excess of freshly prepared solution of bromine. Record the color.
Nitric acid test : is specific identification of the anthraquinone glycosides. To 5 ml solution add 2 ml of concentrated nitric acid. Record the result.