Page 82 - phytochemistry II -pharmD general
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Action and uses
Strychnine is extremely toxic. It is used in veterinary medicine as CNS
stimulant and tonic. It is used as antidote in barbiturate poisoning. It is also used
as rodenticide. Strychnine has been, and is still being misused as a general tonic
and in aphrodisiac preparations. Strychnine is a potent stimulant of the CNS, and
in toxic doses it causes contractions of many muscles, leading to tonic or spinal
convulsions.
Brucine is less toxic than strychnine. It is sometimes used as CNS stimulant.
Commercially it is used as alcohol and oil denaturant
Hemitoxiferine
A degradation product of strychnine is hemitoxiferine which can be easily
converted to its dimmer (toxiferine); the valuable skeletal muscle relaxant alkaloid,
the latter being the main active principle of Calabash curare.
+
N CH3
-
Cl
N
HH O
Hemitoxiferine
Physostigma alkaloids
The seeds of Physostigma venenosum (Leguminosae) contains some indole
alkaloids, the main one being physostigmine, which is also known as eserine.
Eserine is present in the cotyledons of the seed to the extent of 0.04-0.3%, the
average content being 0.15%.
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