Physostigma venenosum. Calabar bean, Ordeal Bean, Chopnut   Family: Leguminosae      
DO NOT USE THIS HERB IN ANY FORM
USES- Extremely poisonous- Schedule 1.
PART USED: Ripe seeds
Rarely used medicinally except as a source of physostigmine, which is an anticholinesterase inhibitor. It is used mainly in ophalmology as a miotic and as an antidote to anticholinergics such as atropine.[1]
The beans were originally used as an ordeal poison by tribes in West Africa for persons accused of witchcraft.[1]

ORIGIN: West tropical Africa.
DESCRIPTION: The Calabar Bean is a woody annual climber. Flowers; papilionaceous followed by pods containing 2-3 dark brown or blackish seeds. Seeds; kidney-shaped, up to about 3 cm long, 1.5 cm broad and 1.5 cm thick, with the hilium extending along the whole convex side.
References
Inner Path can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally. 
Constituents
Alkaloids; mainly physostigmine (ererine),with eseramine, isophysostigmine, physovenine, geneserine, calabatine, calabacine.[1]


References
1. Pharmocognosy, 12th Ed. Trease, G. E. and Evans, W. C. Pub. Bailliere Tindall (1983) UK
Research

Development of physostigmine from a poisonous plant to an antidote. One of the most important drugs in the development of modern medicine? [Article in Norwegian]
Rygnestad T.
Abstract
Physostigmine was originally isolated from the Calabar Bean, which was used for ordeal by poison in West Africa. The main alkaloid was isolated in 1864. It acts through inhibition of acetylcholinesterase, and has been of major importance in elucidating the kinetics and configuration of the enzyme. Physostigmine has been important for our understanding of neurohumoral chemical transmission, and in mapping the cholinergic nerves. It was the first antagonist to curare, and has been widely used for various therapeutic purposes. Today it has been largely replaced by more efficient and safe drugs. It is still used as an antidote to poisoning from various psychopharmacological drugs, and to treat postoperative somnolence and respiratory depression. It is considered a potent antidote to organophosphorous poisoning and is used experimentally to treat Alzheimer's disease.
PMID: 1579914  Tidsskr Nor Laegeforen. 1992 Apr 10;112(10):1300-3. ncbi.nlm.nih.gov