Toxic Honey (mad honey)

 

Toxic Honey (mad honey): 

Honey produced from the nectar of Rhododendron ponticum contains alkaloids that can be poisonous to humans, while honey collected from Andromeda flowers contains grayanotoxins, which can cause paralysis of limbs in humans and eventually leads to death. Grayanotoxin is derived from the leaves, twigs, or flowers of rhododendron and also from secondary products such as honey. It is the latter that has brought attention to this natural toxin as there are many reported cases of poisoning due to ‘mad honey.’

Many plants like Rhododendron, Pieris, Agarista and Kalmia, contain diterpene grayanotoxins. Consumption of grayanotoxin containing honey may result in intoxication specifically characterized by dizziness, hypotension, and atrial-ventricular block.

Mechanism of action: 

Symptoms are caused by an inability to inactivate neural sodium ion channels resulting in continuous increased vagal tone. Grayanotoxin only binds to the activated conformation of sodium channels. Normally, voltage gated sodium channels are activated only when the cell membrane potential reaches a specific threshold voltage. This activated conformation allows for an influx of sodium ions resulting in cell depolarization, followed by the firing of an action potential. At the peak of the action potential, voltage-gated sodium channels are quickly inactivated and are only reset once the cell has repolarized to resting potential. When grayanotoxin is present, binding induces further conformational changes that prevent sodium channel inactivation and lead to a prolonged depolarization.  Scientific evidence for the medicinal properties of grayanotoxin containing preparations, such as honey or herbal preparation in use in folk medicine, is scarce, and such use may even be harmful. Prolonged sodium channel activation and cell depolarization leads to overstimulation of the central nervous system. Physical symptoms from grayanotoxin poisoning appear after a dose-dependent latent period of several minutes to approximately three hours.

Sign and symptoms: 

The most common clinical symptoms include various cardiovascular effects, nausea and vomiting, and a change in consciousness. The cardiovascular effects may include hypotension (low blood pressure) and various cardiac rhythm disorders such as sinus bradycardia (slow regular heart rhythm), Brady arrhythmia (slow irregular heart rhythm) and partial or complete atrioventricular block.

Other early-onset symptoms may include diplopia and blurred vision, dizziness, hyper salivation, perspiration, weakness, and paresthesia in the extremities and around the mouth. In higher doses, symptoms can include loss of coordination, severe and progressive muscular weakness, and electrocardiographic changes of bundle branch block and/or ST-segment elevations as seen in ischemic myocardial threat, and nodal rhythm or Wolff-Parkinson-White syndrome.

Bees that collect pollen and nectar from grayanotoxin containing plants often produce honey that also contains grayanotoxins. This so called mad honey and it is common cause of grayanotoxin poisoning in humans. Mad honey is deliberately produced in some regions of the world, most notably Nepal and the Black Sea region of Turkey. In Nepal, this type of honey is used by the Gurung people for both its perceived hallucinogenic properties and supposed medicinal benefits. In Turkey, mad honey known as deli bal is also used as a recreational drug and traditional medicine.

 

#toxic honey #mad honey