Anthraquinone glycosides

Anthraquinone glycosides
There are stimulate cathartics and exert their action by increasing the tone of the smooth muscle in the wall of the colon and stimulate the secretion of water and electrolytic into the large intestine. After the oral administration , the anthraquinone glycosides are hydrolyzed in the colon by the action of enzymes of the micro flora to the pharmacologically active free aglycone which usually produce their effect in 8 – 12 hours after administration. Cascara & senna the mostly drag used.
The anthraquinone hydrolyzed to give aglycone , which are di , tri , or tetra – hydroxyl anthraquinone , also there are anthrone , di anthrone , and oxanthrone.



Senna – Leguminosae

Definition: Consists of the dried leaflets of Cassia senna (Alexandrian senna)

Senna – Constituents
active glycosides: Sennoside A Sennoside B
Sennoside C & Sennoside D
Rhein
Aloe-emodin
Mucilage
Calcium oxalates
Resin
Senna – Uses
Laxatives (habitual constipation or occasional use).












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.