Oleander (Nerium oleander)

Houston... we have a toxin!

All parts of Nerium oleander are toxic, but what you may not know is why.  Nerium oleander contains cardiac glycosides called Oleandrin and Neriine.  The specific mechanism of action of these toxins is that they destroy the concentration gradient of the K+ and Na+ ions in the neuron
Oleander with flowers thanks to Andrew ButkoOleander branch thanks to Francisco Manuel Blanco
This then would inhibit nerve cells in the heart from firing and eventually stop your heart.  Side effects from this would be vomiting and an irregular heart rate.  One may also sweat profusely and have diarrhea.  Most of the time if a human ingested this organism they would vomit immediately because of the awful taste exhibited by this plant, however if somebody could not taste it or had a very tough stomach they could be putting themselves fatally at risk. 
Oleandrin chemical structure thanks to Edgar181

As you can see in this picture of the toxin there are alcohol groups, a carbonyl group, an 2 ester groups.Oleander growing in Hawaii thanks to Forest and Kim Starr

This is a great defense technique because either a predator is going to eat it and die, or throw it up and then never try it again.  The reality is that there have not been many reported cases of human death to this plant; however there have been many livestock and pets that have died to this organism trying to consume it.  It is important to remember to never consume any part of this plant or even burn it because that will cause one to get the toxins into their body and potentially die.

Check out these other toxic organisms: The Hobo Spider, Inocybe geophylla and The Arizona Bark Scorpion.

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