ABSTRACT
Physostigma venenosum, also known as the Calabar or ordeal bean, is a legume endemic to West Africa. It was found there by Scottish missionaries in the early 19th century and its extremely poisonous seeds brought back to Scotland where it was investigated scientifically. Myasthenia gravis is a rare autoimmune condition where the body produces antibodies to the acetylcholine receptors at the neuromuscular junction, so the muscles do not receive enough acetylcholine to function normally. The use of physostigmine to treat myasthenia gravis was discovered by Dr Mary Walker MRCP, working at St. Alfege’s Hospital, Greenwich, UK. Neostigmine remains a treatment of choice for the symptoms of myasthenia as it does not pass through the blood-brain barrier. Fraser’s thesis, submitted in 1862, detailed the systemic effects of physostigmine and soon a number of studies examining the effects on a wide variety of animals were published.
