Agriculture Reference
In-Depth Information
exerts its cholinesterase inhibitor effect in both the periphery and CNS. It dilates the blood vessels
and has a slowing effect on the heart. It has been found useful as an antidote for toxicity due to
strychnine, nicotine, curare, and atropine and as an adjunct in medication for myasthenia gravis. It
was formerly used in clinical medicine as a postoperative medication after abdominal surgery to
prevent adhesion by stimulation peristalsis.
In modern experimental medicine, physostigmine remains a safe and quite unique agent wher-
ever increase of acetylcholine in the brain is necessary, examples being intoxications with anticho-
linergic drugs, recovery from anesthesia, and in psychiatry. Physostigmine is being investigated not
only for its role in alleviating symptoms of Alzheimer's disease, but also for its capacity to counteract
opiate-induced respiratory depression without abolishing analgesia.
853
Eseroline, the first metabolite
of physostigmine, is being investigated for its opioid-like and cholinesterase-inhibiting properties.
There is a possible application of physostigmine into spinal liquor for its beneficial effects.
857
Toxicity —
Calabar bean has been used in the southeastern region of Nigeria, from where it
derived its name, as a ritual plant and ordeal poison. In ancient times, suspected criminals, witches,
and people accused of breaking one of the taboos were often forced to drink from a decoction made
from the esere seeds. If the accused vomited the poison and lived, the accused was declared innocent,
but if guilty, then the verdict of the gods was accepted and the victim was buried without any normal
funeral rites. It has a sedative action on the spinal cord, which results in paralysis of the lower limbs
and death by asphyxia and, in large doses, concomitant paralysis of the heart. The ordeal trial ratio-
nalized that an innocent person was likely to be brave and swallow the decoction in a gulp, which
would irritate the stomach and cause vomiting of the drug; the guilty person will be frightened by
guilt and would likely drink the poison slowly, with the attendant gastrointestinal absorption and then
toxicity. It appears that the elders of the village were aware of the nature of this poison since it fea-
tured prominently among the secrets passed on to the initiates of the highly esteemed
Ekpe cult
and
in some male puberty ceremonies. When used as a form of capital punishment or suicide, the whole
seed was to be chewed, or the drug could be powdered and administered as an enema. The villagers
also understood that burning or boiling of the seeds greatly reduced, if not eliminated, the toxicity.
PICRALIMA NITIDA
Botanical Name —
Picralima nitida
(Stapf) Th. & Dur.
Synonyms —
P. klaineana
Pierre
, P. macrocarpa
Chev
., Tabanaemontana nitida
Stapf.
Family —
Apocynaceae
Common Name —
Akuamma seeds
African Names —
Ashanti (Twi): ekuama; Igbo: osi, osu-igwe; Idoma: otosi; Yoruba: erin
