In September 1978, Bulgarian writer and dissident Georgi Markov was living in London and working
for the BBC.
Almost ten years earlier, he had defected from his country and been deemed a traitor
to Bulgaria, which was ruled by an authoritarian government behind the Iron Curtain.
One day on his way to work, Markov felt a sudden pain in his leg.
It seemed that a passerby had hit him with the tip of their umbrella.
But over the next few hours, it became clear that this was no accident.
Markov proceeded to experience fever, muscle pain, swollen lymph nodes, and heart problems.
He was admitted to the hospital, but within four days, he was dead.
[1]
When medical experts conducted an autopsy, they realized the jab with the umbrella had
administered a deadly toxin directly into Markov’s muscle - a toxin produced from
one of the world’s most deadly plants.
There are many dangerous plants in the world.
There’s the manchineel tree that grows in the tropical regions of North and South America,
and which is so toxic that if you stand under it during a rainstorm, your skin will blister.
A tree that grows in Southeast Asia, the pong-pong, is sometimes called the “suicide tree”
because of the toxicity of its fruit.
In the southwestern Indian state of Kerala, fruit from this tree is responsible for 50%
of all plant poisonings, and is thought to have killed more than 500 people between 1989
and 1999 alone.
[2]
Even tobacco is a deadly plant, considering how many millions of people die each year
of illnesses related to smoking.
But there are two plants in particular that have been used by spies, murderers, and assassins
for thousands of years—the castor bean plant and the deadly nightshade.
Both of them are so toxic that eating just a handful of their berries or seeds would
be enough to kill an adult within a couple days.
And yet the very chemicals that make deadly nightshade and castor bean plants so dangerous
have also been found to contain valuable pharmacological properties.
They’re used in everything from cancer treatments to antidotes to deadly nerve gasses.
What makes these plants so unbelievably deadly?
And how on earth did we figure out the positive side effects of these deadly shrubs without
causing a lot of accidental poisonings?
Ricin is one of the most toxic compounds produced by plants and has been used in everything
from political assassinations, like in the umbrella assassination, to fictional narratives
like “Breaking Bad.”
Thanks to the ubiquity of the shrub that it comes from, the castor bean plant, ricin is
also one of the most common biological agents used
in biocrimes.
What’s most remarkable about the plant are its seeds, which are commonly called “beans.”
A large plant can produce 150,000 seeds every season and they contain a valuable commodity
as well as a deadly poison.
Each seed is about 50% oil, which has been used for fuel and as medicine.
But the seeds also contain ricin, a poison so deadly that it only takes 3 to 6 to kill
an adult.
[3]
Ricin is one of the most poisonous naturally-occurring substances known, but how quickly it kills
someone, and how it affects the body, depends largely on the way it’s administered.
[4]
Inhaling ricin and having it injected into the muscle are far more dangerous than ingesting
it.
The lethal dose for inhalation of ricin is 3-5mcg/kg (LD50 0.003 mg/kg) whereas the lethal
dose for oral consumption is 20mg/kg.
This is because ricin works by inactivating ribosomes, which are structures made of RNA
and proteins that create all the proteins necessary for cells to function.
Without ribosomes, cells die—and ricin causes cell death on a massive scale.
One molecule of ricin toxin can inactivate 1500 to 2000 ribosomes per minute.
[5]
When ricin enters the body, it affects whichever organ systems are closest.
That means if it’s inhaled, it destroys lung tissue, causing fluid buildup, alveolar
inflammation, and necrotizing pneumonia.
Basically, your lungs are destroyed and you die.
And ricin powder attacks have been attempted at least twice that we know of, with envelopes
containing ricin being sent to the US Senate in 2004 and President Obama in 2013.
[6]
Things aren’t much better if you ingest ricin: you’ll have stomach cramps, vomiting,
diarrhea, ulcers along your GI tract, and possible renal failure.
But because doctors can treat those symptoms in the hospital, you still might survive.
Would-be murderers in the US, the UK, and Germany have all been arrested for attempting
to extract ricin, and the FBI will even investigate Americans simply for planting castor beans
on their property.
Even processing the seeds for oil can come with dangers.
A manufacturing plant in Brazil, one of the main producers of castor oil, reported more
than 150 cases of bronchial asthma, including nine deaths.
When health officials investigated the incident, they found that processing methods of the
castor bean had sickened the workers.
[7]
Given how deadly ricin is, it should come as no surprise that plenty of countries have
investigated its use as a chemical weapon.
The United States War Department researched whether it could be used as a toxic dust to
spray on the battlefield, or to coat bullets and shrapnel with, during WWI.
But ricin is unstable under heat, limiting its use in shells.
And even though the US conducted more tests on ricin during WWII, it was ultimately never
deployed.
[8]
Treaties on the use of bacteriological and toxin weapons later prohibited the use of
ricin–but that doesn’t mean governments haven’t tried.
In the 1980s, Iraq aerosolized ricin and tested it in animal experiments, though they never
used it for warfare.
But ricin is much less toxic than botulinum and anthrax, so it’s not actually as useful
for mass murder.
That’s why it’s become one of the poisons of choice for political assassinations.
But another plant lurks in the forests of Europe, its berries dark, delicious, and even
more deadly.
Atropa belladonna, sometimes known as the deadly nightshade, belongs to same family
as plenty of our edible favorites, like tomatoes, potatoes, and peppers.
But even though the purple berries of the deadly nightshade are apparently sweet, they
are far from being safe for consumption.
They contain multiple dangerous alkaloids, including atropine and scopolamine, and have
a long history of being used in poisonings.
Even their scientific name suggests how dangerous they are.
According to Greek mythology, the three Fates were responsible for dictating human lives.
Lachesis measured the thread of destiny at birth, Clotho spun it, and Atropos ended life
by cutting the thread.
[9]
Yet even though deadly nightshade was used to murder Roman emperors and political rivals,
it also had its place in medicine.
Renaissance women put it in their eyes to make their pupils larger–a practice ophthalmologists
still use today to dilate the eyes.
It was used to bring on delirium and hallucinations, including the famous “flying ointment”
made by witches, and helped in treating pain from childbirth. [10]
Clearly, even before the discovery of organic chemistry, humans understood something crucial
about these deadly plants: the dose makes the poison.
While castor beans deliver all their toxicity with one chemical punch in the form of ricin,
deadly nightshade includes more of a cocktail, with the most potent toxins being atropine
and scopolamine.
Both act on neurotransmitters, and target acetylcholine.
Normally, this chemical carries messages between the nervous system and the muscles.
When it gets to the end of a synapse, it binds to acetylcholine receptors, which play a variety
of roles, from regulating heart rate to stimulating sweat glands.
Atropine and scopolamine are acetylcholine receptor antagonists—basically, they compete
with acetylcholine for access to that connection between the nervous system and the rest of
the body.
When these toxins bind to the acetylcholine receptors, they prevent acetylcholine from
transmitting messages between the nervous system and the rest of our muscles and organs.
And this causes a whole host of problems.
[11]
The body’s temperature regulation is thrown off, causing fever.
The pupils of the eye dilate, sometimes to such a degree that the iris is invisible.
Salivation is suppressed, causing extreme thirst.
And patients might exhibit delirium, hallucinations, and seizures.
The plant itself was famously used to poison Roman emperors hundreds of years ago, and
some scholars think it’s what gave Juliet a death-like appearance at the end of Shakespeare’s
play “Romeo and Juliet.”
But once the chemical atropine was isolated in 1830, that by itself became more commonly
used in poisonings.
One of the most bizarre episodes happened in the UK in 1994.
Biologist Paul Agutter was able to get atropine from his university’s toxicology lab and
use it to poison his wife.
Because the chemical is extremely bitter, he dosed multiple bottles of tonic water with
the poison, leaving some of the bottles at a supermarket to cover his tracks and bringing
the most heavily dosed bottle home to make his wife a gin and tonic.
Multiple people fell ill with atropine poisoning, but none had a dose as high as Agutter’s
wife.
Fortunately, her gin and tonic was so bitter that she drank only half of the cocktail,
and was able to survive.
[12]
This kind of poisoning is rare, since atropine is harder to isolate from deadly nightshade
than ricin is from castor beans.
But the other chemical in the plant, scopolamine, has had a growing reputation as a dangerous
poison because it’s used in robberies and sexual assault.
After the victim is dosed, they become highly suggestible and often suffer amnesia after
the event–making it much easier for the criminal to get away.
[13]
But, surprisingly, the properties of both the castor bean plant and deadly nightshade
that make them so dangerous can be harnessed by us in a way that turns them from poison,
to panacea.
Although deadly nightshade and the castor bean plant are very dangerous, they both also
play a big role in medicine and other industries.
Castor bean especially is a valuable commodity, thanks to its oil.
Soybeans have 15 to 20 % oil, and sunflower seeds have 25 to 35% oil, whereas castor beans
have 40 to 55% oil.
[14]
And the chemical properties of the oil mean its viscosity doesn’t change much with higher
temperatures, so it is especially good at lubricating hot metal.
It’s one of the best oils for racing and jet turbine engines.
What’s more, researchers have found that castor oil could be an excellent biodiesel,
even more effective than plants like corn and soybeans, and the plant is hardy enough
to be used in bioremediation, to clean up soil that’s been contaminated with heavy
metals like copper and lead.
[15]
Deadly nightshade also has a role to play in medicine, both with common ailments and
in more extreme cases.
Atropine and scopolamine have all been modified to treat asthma, motion sickness, provide
sedation and pain relief during childbirth, treat Parkinson’s disease, and as an antipsychotic
drug.
And atropine has one particularly surprising function: it’s an antidote to nerve gas
poisoning.
In a healthy individual, acetylcholine’s action is stopped by an enzyme called acetylcholinesterase.
This keeps acetylcholine levels regulated and in a healthy balance.
But nerve gasses like sarin, soman, and VX binds to the enzyme, and blocks its action.
Therefore, acetylcholine builds up out of control, binding to the receptors unchecked.
This causes excessive production of fluids, vomiting, difficulty breathing, and heart
problems.
But atropine can work to fix this.
Because atropine blocks acetylcholine receptors, it counteracts the effects of nerve agents.
Even if a lot of acetylcholine builds up between cells, it can’t actually make the connection.
[16]
So while nerve agents are extremely lethal, they can be countered by a dose of atropine
quickly administered—just like Nicholas Cage’s character does in “The Rock”
after being exposed by nerve gas.
That said, its a very tricky balance.
There’s a possibility of atropine poisoning if you take too much as an antidote, or take
it without being exposed to nerve gas.
Duri ng the Gulf War, atropine auto-injectors were distributed across Israel in case of
a gas attack, and nearly 300 cases of children accidentally poisoning themselves were reported.
Luckily, there were no fatalities. [17]
All this is to say that both these plants can still be dangerous, even when put to helpful
purposes.
And plenty of people get poisoned just from consuming the berries or seeds of the two
plants, so remember to never, ever eat something on a trail if you are not 100 % confident
you know what it is, and that it’s safe.
Learning what these plants look like is the best way to avoid stupidly dying.
In fact, learning in general evolved as a concept so we can avoid stupidly dying.
And we can even use learning for other things too.
I personally, have dabbled in learning from time to time, and find that life does improve
when I dust off some neurons.
It helps me in my work, it helps me to gain confidence, and it helps me to feel a part
of the big, scary, complicated world that we live in.
And to really knock the cobwebs out, I use Brilliant.
Brilliant dot org is the best way to learn math and computer science interactively.
There are thousands of lessons, from foundational and advanced math to AI, data science, neural
networks and more, all of which I have used to help me write these videos.
There are also in depth courses for things that I use in my daily life, like the Geometry
fundamentals course.
I have a vague memory of taking geometry first year of high school, but thats about it.
And it turns out, geometry is pretty important in this world.
When planning a garden, redesigning your bathroom, or arguing about the fastest way to get somewhere,
geometry is literally everywhere.
So lately I have enjoyed diving in to the Geometry Fundamentals course to brush up and
strengthen these skills.
The course is sometimes challenging, but Brilliant doesn’t penalize you or impede your progress
- instead they give you an in depth explanation to guide you to the right answer, so you can
learn from your mistakes.
Its easy to learn in this low pressure environment, and most importantly its easy to learn by
doing.
The interactivity of Brilliant is my favorite part.
I love learning new things, while moving little robots around, or interacting with sliders
and levers that really show me how things work, rather than being told in dense blocks
of text.
To try everything Brilliant has to offer—free—for a full 30 days, visit brilliant.org/realscience
or click on the link in the description.
The first 200 people will get 20% off Brilliant's annual premium subscription, and every sign
up immensely helps this channel.