CALABAR BEAN
Physostigma venenosum Balf. 

PLAN OF THE MONOGRAPH :
 
 Plant
 History
 Intoxication
 Constituents and uses




PLANT :  Calabar bean, ordeal bean, chop nut. Physostigma venenosum Balf. Fabaceae.

It is a climbing creeper, growing in West Africa (Nigeria, Cameroon, Gabon)in marshy places. Seeds measure 2-3 cm long and 12-15 mm large, brilliant brown, very hard, with scar (2-3 mm large) on convex side.


HISTORY :

In the past, natives of the coast of Calabar, cultivated Calabar bean. The plant was sacred and used as judicial poison . During a ceremony, (= esere or djirou) the prisonner was forced to swallow beans (30 to 100), if he womited the beans, he was considered innocent, if he died, he was considered guilty. Generally, the outcome was fatal.


INTOXICATION :

Eserine is a parasympathomimetic.
Symptoms of intoxication are : severe thirst, sialorrhea, myosis (contraction of the pupil), nausea, vomiting, muscular weakness, fall of blood pressure, convulsions, and dead. Consciousness is not impaired.


CONSTITUENTS AND USES :

The seed contains 0,2 to 0,3 % of alkaloids, main substance is physostigmine (eserine). Others alkalo´ds are : la nor-physostigmine, eseramine, physovenine and geneserine.

In medicine eserine is used for myasthenia, it is also curare-antidote in anesthesia.