Page 127 - Medicinal Plants_PharmD general
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O O
O 2H
Anthraquinone HH
O Anthrone
O
H OH
Oxanthrone Dianthrone O
Properties:
-Anthraquinone derivatives are often orange red compounds.
- They are usually soluble in hot water and dilute alcohol.
-When alkali is added to powdered drugs containing anthraquinone
derivatives, a red or purple colour is formed and when alkali is added to
powdered drugs or to sections, the red colours serve to locate
anthraquinone derivatives in the tissues e.g. in the cells of medullary rays
of cascara and frangula barks.
Borntrager’s test is often used for the detection of anthraquinone
derivatives. The powdered drug is macerated with an immiscible organic
solvent e.g. ether, benzene and after filtration, aqueous ammonia or caustic
soda is added when a pink red or violet colour appears in the aqueous layer
indicating the presence of free anthraquinone derivatives.
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