, NERIUM OLEANDER THEVETIA , PINK LAUREL, YELLOW LAUREL, decorative but toxic, poisoning,cardiotonic cardenolides

translated from a website in French

NERIUM
OLEANDER

THEVETIA
YELLOW OLEANDER
LUCKY NUT

le Laurier rose Nerium oleander
NERIUM OLEANDER
THEVETIA NERIIFOLIA = THEVETIA PERUVIANA

APOCYNACEAE

The oleander, Nerium oleander, is a shrub native to the Mediterranean region, with evergreen foliage, with pink flowers but sometimes white or red.

It is a shrub very resistant to drought but which also adapts to humid tropical climates, it is sensitive to cold and fears frost, it spends the winter in a greenhouse in temperate countries with cold winters.

Oleander is very common in warm countries, both in gardens and along roads and highways.

It is very popular for its evergreen foliage even in arid areas and its many decorative flowers.

it naturalizes easily and appreciates rocky areas near temporary watercourses and valley bottoms.

The yellow laurel, Thevetia peruviana = Thevetia neriifolia, comes from tropical America but has been widespread in most warm regions, it is a tree with elegant foliage, long and narrow leaves, and lemon yellow flowers.

It is planted in many gardens and also in public places including schools.

It is easily acclimatized in tropical areas and is found, naturalized, in wasteland, near illegal dumps, near irrigation canals.



le Laurier jaune Thevetia peruviana = neriifolia

NERIUM OLEANDER PINK LAUREL THEVETIA YELLOW LAUREL LUCKY NUT TOXIC CARDIOTONIC CARDENOLIDE



 

These two decorative trees are part of a botanical family (apocynaceae) whose species are often toxic but which provide medicine with many pharmacologically active molecules that are interesting for their chemical structure which serves as a basis for the synthesis of new drugs.

All parts of these two trees, oleander, Nerium oleander, and thevetia, Thevetia peruviana = Thevetia neriifolia, contain substances of interest in pharmacology and in traditional herbal medicine, mainly cardiotonic heterosides.




CHEMICAL COMPOSITION AND PROPERTIES

NERIUM OLEANDER PINK LAUREL: LEAVES, LATEX, WOOD

The most characteristic compound of oleander is oleandrine, an heteroside with a steroid structure, which chemically and pharmacologically resembles ouabain and digoxin, two cardiotonics widely used in heart failure.

The action of oleandrine is twofold: interaction with the Na + and K + pump of cardiac muscle cells and direct action on the vagal tone and therefore the nervous regulation of heartbeats.

The sodium-potassium pump or Na + -K + ATPase is an enzymatic system which controls the exchanges between sodium and potassium intra and extracellular, which regulates the activity of the cell and its resting.
In the case of the myocardium (heart muscle), this decides the extent of the heart's contraction and its rate of contraction.

Oleandrine and its derivatives block the action of this enzymatic system, and thus prolong the contraction of the heart.
The second important action of oleandrine is on the regulation of the pneumogastric (vagus) nerve (10th cranial pair) which innervates among other things the heart and the digestive organs. The increased "tone" of the vagus nerve causes a slowing of the heart rate and digestive disorders (nausea, vomiting).

Oleandrine and these derivatives are present in all parts of oleander (leaves, flowers, latex sap, wood, roots), their quantity is variable over time and depending on the growing conditions. Oleandrine is soluble in water (flowerpot, cutting pots) and is present in smoke when even dry oleander is burned.
It appears that arid conditions increase the concentration of cardiac glycosides in oleander (up to 2%).



THEVETIA PERUVIANA, T. NERIIFOLIA, YELLOW LAUREL: LATEX, SEEDS

All parts of the yellow laurel or thevetia contain a toxic, colorless or white latex turning black in the air, but it is the seeds that are considered to be the most poisonous.

The fruits are globular and green (3 to 5 cm in diameter) then turn black when drying.

The active substances are cardiac glycosides whose structure is similar to that of oleandrine: the main ones are thevetin A and B and peruvioside.

The action of thevetins on the sodium-potassium or Na + -K + ATPase pump enzymatic system is comparable to that of other glucosides (ouabain, digoxin, oleandrine).

They are also substances soluble in water, resistant to desiccation and present in the smoke of yellow laurel, thevetia, fresh or dry.

USES



POISONING BY PINK LAUREL AND YELLOW LAUREL

All mammals and most vertebrates are sensitive to the action of cardiac glycosides of the oleandrin or thevetin type.

Intoxication is accidental or deliberate. The oleander and especially the yellow laurel are indeed quite often used for suicidal purposes.

In humans oral poisoning is rapid and is initially accompanied by digestive disorders: nausea, vomiting, diarrhea.
These disorders make it possible to partially eliminate the toxic products which have not had time to be absorbed in the digestive system.
The action on the heart is rapid: slowing of the heart rate (bradychardia) with rhythm disturbances (arrhythmia, fibrillation) sometimes up to cardiac arrest.
Redness can be observed around the mouth in case of poisoning by oleander.

The lethal quantity of leaves or seeds is very variable and depends a lot on the precocity of the vomiting. The annals of toxicology give sometimes contradictory information: infant mortality with just one leaf of oleander or the absence of major disorders after ingestion of several leaves. Adults are of course more resistant.
In the absence of serious heart problems, "cure" takes 3 to 4 days to eliminate the cardiac glycoside.

We can look for the presence of cardiac glycosides in the blood using the immunological test of digoxin, this also allows to quantify the extent of intoxication and therefore the risk of life.

Symptomatic treatment is controversial (atropine, lidocaine, intravenous magnesium).

The use of antibodies specific for digoxin (monoclonal antibodies) to neutralize the glucosides of both oleander and thevetia is the best treatment and is recommended in cases of severe poisoning, although difficult to find in developing countries. .

Herbivores can poison themselves with oleander leaves.
Dry leaves are usually the cause because the fresh oleander leaf is rather repulsive unless the animal is hungry.
30 to 60 g of fresh leaves would be potentially fatal for adult cattle and 4 to 8 g of leaves would be potentially fatal for small ruminants (especially sheep).
The water in which the leaves or branches of oleander have macerated is also toxic to animals.
We find in the scientific literature human poisoning with oleander (oleander) by snails as well as by honey in areas where oleander are very abundant and where bees have no other floral resources ( this is strange because oleander has no nectar, may be the pollen ou tree exsudate).

In some countries in South America, thevetia latex or thevetia (yellow laurel) seeds are used to eliminate rats and stray dogs.

The latex of the two laurels is irritating to the oral mucosa and the eyes. This is the minimum intoxication of children who "drip" on the leaves and play in the oleander bushes.

Some traditional healers in North Africa recommend foot baths with a diluted infusion of oleander leaves which can cause fairly serious chemical burns that can lead to amputation of the toes.


OLEANDER PINK LAUREL AND YELLOW LAUREL IN PHYTOTHERAPYE

Cardiac or digitalis glucosides are used less than in the past.

Their use is limited to heart failure especially when there is atrial fibrillation (the contraction of the atria of the heart is very disturbed) with increased heart rate (tachycardia).

The problem with these substances is the small difference between the effective dose and the toxic dose.

In Western medicine, extracts of digitalis (digoxin) are mainly used in prolonged treatment and strophantus (ouabain) in emergency treatment.
The extracts of oleander and yellow laurel have been used in the same way but have fallen into disuse in France. Nevertheless, there were still recently extracts of thevetia (yellow laurel) dosed with thévetin in certain European countries (Italy, Germany, Holland).

The usual oral dose is in adults:
Five hundred micrograms to two milligrams per day in several doses of thevetin A and B





OLEANDER PINK LAUREL AND YELLOW LAUREL THEVETIA AGAINST CANCER

We have seen above that the glucosides of these two plants modify the functioning of the Na + K + pump.
Some cancer cells absolutely need the proper functioning of this enzymatic system to reproduce and quite simply to survive because their metabolism is more accelerated than that of healthy cells.

We can therefore try to block the development of certain cancers by these relatively non-toxic substances at effective doses.

Recently (2009) a first trial (phase I) in humans was launched with oleandrine (oleander) in patients with advanced tumors (bladder, colon, uterus) and the initial results were promising, but to my knowledge the later trials has been cancelled.


ABSTRACT

NERIUM OLEANDER AND THEVETIA, DECORATIVE BUT TOXIC TREES

Oleander is Mediterranean, yellow laurel or thevetia, South American; both are often planted as garden trees or to make flowering hedges in warm regions.
Their leaves or seeds contain toxic substances but which in low doses can be used to regulate the heart and strengthen its contractions.
Their extracts are currently being studied to fight cancer but with few positive results.