Page 7 - phytochemistry II -pharmD general
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Properties of Alkaloids
I- Physical Properties:
Most of alkaloids are:
1. Bitter in Taste . √
2. Odorless. √
3. Colorless.
4. Crystalline
5. Optically active.
Exceptions:
➢ Colored alkaloids: e.g. Colchicine, Berberine,Psychotrine
➢ Liquid alkaloids
• Non-volatile liquid e.g. Pilocarpine , Scopolamine
• Volatile-liquid e.g. Pelletierine Coniine ,Nicotine
Optical activity of alkaloids:
Ciral centers → different isomers.
Generally, the levo rotatory l (-) isomers more active pharmacologically than
dextro rotatory d (+) isomers of the same alkaloid.
Exceptions:
• d(+) pilocarpine, d(+) tubocurarine and d(+) quinidine are medically used.
• Another exception is the optically inactive papaverine (has therapeutic
effect).
• Sometimes, the difference in the opt. activity of the same chemical
structure cause change in therapeutic uses .e.g.
l (-) Quinine is antimalarial, while
d (+) Quinidine is used in treatment of auricular fibrillation.
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