Toxicity of the Tree Parts:
The tree and its parts contain strong
toxins, some unidentified. Its milky white sap contains
phorbol and other skin irritants, producing strong allergic dermatitis.
[2] Standing beneath the tree during rain will cause blistering of the skin from mere contact with this liquid (even a small drop of rain with the milky substance in it will cause the skin to blister). Burning the tree may cause
blindness if the
smoke reaches the eyes. The
fruit can also be fatal if eaten. Many trees carry a warning sign, while others are marked with a red "X" on the trunk to indicate danger. In the French Antilles the trees are often marked with a painted red band a few feet above the ground.
[3]
The tree contains:
12-deoxy-5-hydroxyphorbol-6gamma,
7alpha-oxide,
hippomanins,
mancinellin, and
sapogenin,
phloracetophenone-2,
4-dimethylether is present in the leaves,
___________________________________________________
while the fruits possess physostigmine.[4]
The
Caribs used
the sap of this tree to
poison their
arrows and would tie captives to
the trunk of the tree, ensuring a slow and painful death.
A
poultice of
arrowroot (
Maranta arundinacea) was used by the
Arawaks and
Taíno as an
antidote against such arrow poisons.
[5]
The Caribs were known to poison the water supply of their enemies with
the leaves.
Clinical uses
Physostigmine is used to treat
myasthenia gravis,
glaucoma,
Alzheimer's disease and
delayed gastric emptying. It has been shown to improve the short term memory (Krus et al. 1968). Recently, it has begun to be used in the treatment of
orthostatic hypotension.
Because it is a
tertiary amine (and thus does not hydrogen bond, making it more hydrophobic), it can cross the
blood-brain barrier, and physostigmine salicylate is used to treat the
central nervous system effects of
atropine,
scopolamine and other
anticholinergic drug overdoses.
Physostigmine is the
antidote of choice for
Datura stramonium poisoning. It is also an antidote for
Atropa belladonna poisoning, the same as for atropine.
[2] It has been also used as an antidote for poisoning with
GHB as well,
[3] but is poorly effective and often causes additional toxicity, so is not a recommended treatment.
[4]
Bioactivity
Physostigmine functions as an acetylcholinesterase inhibitor. Its mechanism is to prevent the hydrolysis of acetylcholine by acetylcholinesterase at the transmitted sites of acetylcholine. This inhibition enhances the effect of acetylcholine, making it useful for the treatment of cholinergic disorders and myasthenia gravis. More recently, physostigmine has been used to improve the memory of Alzheimer’s patients due to its potent anticholinesterase activity. However, the drug form of physostigmine, physostigmine salicylate, has poor bioavailability.
Physostigmine also has a miotic function, causing pupillary constriction. It is useful in treating
mydriasis. Physostigmine also increases outflow of the aqueous humor in the eye, making it useful in the treatment of glaucoma.
Recently, physostigmine has been proposed as antidote for intoxication with
gamma hydroxybutyrate (GHB, a potent sedative-hypnotic agent that can cause loss of consciousness, loss of muscle control, and death). Physostigmine may treat GHB by producing a nonspecific state of arousal. However, there is not enough scientific evidence to prove physostigmine properly treats GHB toxicity.
Physostigmine also has other proposed uses: it could reverse undesired side effects of
benzodiazepines such as
diazepam, alleviating anxiety and tension. Another proposed use of physostigmine is to reverse the effects of
barbiturates (any of a group of
barbituric acids derived for use as sedatives or
hypnotics).
Side effects
An overdose can cause
cholinergic syndrome.
Other side effects may include
nausea,
vomiting,
diarrhea,
anorexia, dizziness, headache, stomach pain, sweating,
dyspepsia and seizures.
[5]
