September 1, 2020 • 34 mins
Deep in some of the world’s most hard-to-reach places lies a wealth of plant knowledge that could offer the next life-saving cure.
In this episode, James Wong explores how Kew scientists works alongside remote communities on the ground to understand plants’ medicinal properties.
And there’s a history lesson in it too, as James learns of the enormous impact that humble quinine, (found in your G&T), had throughout colonialism through to the world wars.
What is yet to be discovered? And what do we stand to lose if we do not protect and respect world ecosystems?
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And you can share the show or join the conversation on social media with the hashtag #KewUnearthed.
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
James Wong (00:05):
December 7th, 1941, a surprise Japanese aerial attack on the
American Naval Base at Pearl Harbor in Hawaii initiated the
formal entry of the United States into the second World
War. Thousands were killed. The damage was extensive. In addition
(00:27):
to those that died that day, the Pearl Harbor attack
led to a far greater loss of life amongst the
Allied forces. Since the start of the war, malaria had
ravaged forces stationed in the West Indies. Only held at
Bay by a wonder drug from the Dutch East Indies
modern day, Indonesia. The source of this plantations of the
(00:50):
humble Cinchona tree on the Island of Java, where 90% of
the world's Quinine was sourced. Demand for this plant based
malaria cure roared during wartime. But by crippling the Allied
defense through the bombing of Pearl Harbor and the capturing
of Singapore, there was nothing to stop the Japanese from
(01:10):
taking Java and cutting off supplies to their enemies in
the West In the effort to acquire the island's rich
oil fields, Japan also denied its opponents one of the
most crucial medicines in human history, and scientists were forced
to seek out an alternative to the substance that had
enabled Western colonization of the tropics for centuries.
Kim Walker (01:34):
Cinchona has been called a tool of imperialism and that's
because Quinine, which is the active antimalarial chemical found in
the bark, was so important for empire, particularly across 18th and
19th century.
James Wong (01:48):
Today, we find out how plants and medicines have changed
the fortunes of nations, and their roots from forest to
pharmacy throughout history. We'll hear how the hunger for cures
has transformed landscapes, seen powers rise and fall, and altered
human history forever.
Kim Walker (02:07):
Quinine started to gain extra significance for them. So to
be able to control the quality and quantity of supply
became very important. Plantations started to be grown in British India and
Dutch Indonesia.
James Wong (02:19):
And we'll hear what we can learn and how lives
can be saved in the search for modern day medicines.
Dr. Melanie-Jayne Howes (02:25):
Plants are actually brilliant chemists.
James Wong (02:28):
I'm James Wong, and welcome to Unearth Mysteries from an
unseen world from Royal Botanic Gardens, Kew. Today, I'm finding
out how one kind of tree changed the course of
world history. The cinchona tree is native to South America.
(02:51):
Myth has it that in 1630, the Spanish Countess of Chinchon
visited Peru and fell ill with a fever. The substance
given to cure her was the bark of cinchona, which we now
know contains many useful substances, only one of which is
Quinine. And whilst the real story of how cinchona's healing
(03:12):
properties first made it into medicine, remains a mystery, there
are plenty of clues to help us piece together some
of that history. The Royal Botanic Gardens, Kew has one
of the largest collections of cinchona bark in addition to
Herbarium specimens and a wealth of historical records from the
19th century when Quinine was transported around the world. It's this
(03:36):
archive that makes Kew, so compelling for my first guest.
Kim Walker (03:40):
I'm Kim Walker, and I am a PhD student at
Kew. And I work in the Economic Botany Department and
I study that collection of cinchona bark. It does sound
a bit dry, doesn't it studying bark? But actually if
you're going to pick a bark, this is probably one
of the most interesting ones in history. Cinchona bark contains
Quinine which for over 300 years was the only known
(04:02):
malaria treatment in Europe. And also is the flavoring in
everybody's favorite cocktail, the gin and tonic, because it is
the flavoring and tonic water.
James Wong (04:11):
When we talk about malaria, it's quite difficult to picture a world
before cinchona bark was in existence, because malaria wasn't something that was just found in
remote location.
Kim Walker (04:21):
Yeah, absolutely. So it's just slightly out of living memory
now. So not many people realize that we used to have
malaria and Britain all the way up to the first World War.
James Wong (04:31):
So tell me about the history of cinchona bark. How
do we know that it contains Quinine and that that's
an effective treatment for malaria?
Kim Walker (04:39):
That's a really interesting question because when the Spanish entered South
America, which is where cinchona comes from originally, across the
Eastern slopes of the Andes, before this period, malaria, or
at least a very severe forms of malaria didn't exist.
So as the Spanish come in, bringing malaria with them,
and Cinchona trees already grow South America is not very
(05:00):
clear who or when somebody connected that cinchona bark kills
malaria. But it's likely that it would have been indigenous healers, had
really superior knowledge of local botanics and healing. And so
at the (inaudible) , as it were, where new diseases were
entering the country and cinchona may have already been in
use for other things, they would have put two and
(05:22):
two together and found the treatment. We do know that
was around about 1600. And by about the mid 1600s cinchona
bark started being imported into Europe.
James Wong (05:32):
Is this presumably because cinchona bark was really important for
industry at one point in time? People wouldn't be able to
conduct business across large parts of the world, if you
couldn't physically access them while staying healthy.
Kim Walker (05:45):
Absolutely. So cinchona has been called a tool of imperialism
and that's because Quinine, which is the active antimalarial chemical found
in the bark, was so important for empire, particularly across 18th and
19th century. And so, for many different countries within Europe
who are interested in expanding into new territories and colonizing
(06:08):
areas, such as India and parts of Africa, Quinine was
really important because unless you can control disease, whenever you
were to go somewhere that may have something like malaria,
you're more likely to die off than to be able to
enter those places.
James Wong (06:23):
How is Quintin traditionally administered? Was it administered in tonic water?
Kim Walker (06:27):
Tonic water came a little bit later in the 19th century,
which is about the mid 1800s. But originally how Europeans
started to use cinchona was in very traditional ways to
use medicine, which is getting the bark, which is a
very tough material, grinding up into a powder. So you
can crack open all the plant cells and get the
chemicals out, and then dilute it. And the best way
(06:49):
to dilute and extract chemicals quite often is by using
a bit of alcohol. So early ways to dilute it
would have been using wine, or port, or perhaps stronger
spirits like brandy. By the 19th century, it was one of
the largest imports of American drugs imported to Europe. Demand
(07:09):
started to outstrip supply, and it started to be over
harvested in the world by some unscrupulous harvesters. And as this
happened, and as the 19th century grew older and different
empire started to look further afield to colonize new areas,
Quinine started to gain extra significance for them. Around the
early 1900s, different countries, particularly the Dutch and the British,
(07:33):
started to look into how they could get hold of
this tree for themselves to cultivate. Quinine was used all
the way up to the second World War, when supplies
from Indonesian plantations got caught off. Unfortunately, using Quinine to
control the ability to colonize the areas is not a very
(07:53):
nice thing to think about. And for the British and the
Dutch to get hold of these trees, they were going
to have to basically smuggle them out of South America.
And they were justifying that as saving the seeds because
of over harvesting, which is very complicated, because really nowadays
you wouldn't do that. You would work with communities to
bring up the cinchona bark and make it available for
(08:14):
everybody if they chose to. Everything was different then. And
unfortunately, they smuggled out to make plantations in India and Indonesia.
James Wong (08:23):
So in that time, that was really considered par for the core.
So people wouldn't have raised an eyebrow at all about
the idea of taking plant material for one part of
the world, or taking the knowledge of plant material even,
and applying it for themselves. But nowadays we actually have
a term for that bio- piracy and the same way
that you would pirate a bootleg CD or a copy
(08:46):
of a film that you download off the internet. We
would have the same term for biological genetic information, and
also information about how to grow and use plants. Now
I should just point out here that Kim's book, Just
the Tonic a Natural History of Tonic Water, which she co-
wrote with Mark Nesbitt, is a fantastic read. If you'd
(09:08):
like to delve a little deeper into the rich history of
this favorite tipple, then check it out. The Cinchona story
is just one example of how a naturally occurring medicine
played an essential role in the movement of people internationally.
With the current conversation about the British empire and its
legacy, it's fascinating to me to contemplate whether European powers
(09:31):
would have been able to colonize the world's tropical regions
to the same extent, if at all, without this wonder
drug. Or would history have unfolded quite differently? It's amazing
to think that this humble tree might have carried the
course of history upon its delicate branches. Nowadays, scientists are
investigating new substances that can be created using other alkaloids
(09:54):
within cinchona bark. And while science is opening more doors
to plant medicines every day, they are still a constant
source of novel, unexpected compounds. I chatted to Dr. Bente
Klitgaar, Senior Research Leader in Identification and Naming and Head
of the Americas Department at Kew. She's mostly based in
(10:15):
the Herbarium where seven million plant specimens are held. Her
team looks after the two million of them from the
Americas. My first visit to Kew's Herbarium was 15 years ago
now, and I was just starting on my master's. And
it's quite difficult to picture what seven million samples is
like. But to me, it was like going into a
scene from Harry Potter, just floor after floor in this
(10:38):
beautiful old Victorian building, of course, with some modern adjuncts
now. And a Herbarium is to an untrained eye, just
millions of pressed flower specimens.
Dr. Bente Klitgaar (10:48):
They are.
James Wong (10:49):
It's like some kind of someone's hobby just went really
out of control. Why is it important to have so
many just pieces of plant squished between paper?
Dr. Bente Klitgaar (11:00):
They are the ultimate evidence. Because we don't just have
one of each plant species, we have about 80% of
the biodiversity in terms of the generic level, which is
a bit scientific, represented in Kew's Herbarium. So, Kew's Herbarium is one of
the best global collections in the world. And as I said, we can use it for any type
(11:22):
of research, because we don't have to have all one
of each species, we have the whole distribution range. I have
some plants that I have known ever since I started
my career in botany. And these are the legume family that I have been
specializing. I've been doing many things in my career, but
the legume family has always been part, been my friend all
(11:43):
the way along.
James Wong (11:44):
So peas and beans, the legume family. It's such a massive
family. And this includes everything from tiny little herbs in
the Arctic Tundra-
Dr. Bente Klitgaar (11:50):
Exactly, yes.
James Wong (11:50):
... right up to giant Amazonian trees.
Dr. Bente Klitgaar (11:53):
Yes. Some of the biggest emergence in the Amazon are
legumes as well. So I'm going to show you some of
my very, very best friends and my first legume friend.
It's a genus called Brownea. When I started working on
this genus called Brownea, they're rainforest trees. They occur only
in Northwestern, South America. And I can show you-
James Wong (12:13):
Wow, look at that.
Dr. Bente Klitgaar (12:16):
Yeah. Yeah. So, at Key, we are very, very lucky.
There's one in the Palm house, which is Brownea Coccinia,
and there's one at Princess or Wales Conservatory called Brownea grandiceps.
So when I miss them, I can go into one
of these green houses, and they flower as well, they're fantastic. They get up about a football size.
James Wong (12:40):
It looks like something straight out of the movie Avatar.
It's like a giant pompom flower with these really, really
long filaments that are coming out of it.
Dr. Bente Klitgaar (12:48):
Yeah.
James Wong (12:48):
Almost like you've got a big fistful of the showiest
rhododendron and stuck them all together-
Dr. Bente Klitgaar (12:52):
Exactly.
James Wong (12:52):
... and just made them look even more exotic.
Dr. Bente Klitgaar (12:56):
As a young scientist, I decided to work on this
group for my Master's thesis. So I went then and my task was
to understand that the Brownea is species in Ecuador. That was one
task, and the other task was then to understand how the Brownea species
were used in Ecuador. And I wanted to write a book about
(13:18):
children who live in the rainforest. So I actually got
myself a deal with a publisher. And I went and visited
some indigenous communities in the Amazon at the same time.
So I realized-
James Wong (13:35):
Talk about multitasking there. Is there anything you can't do?
Dr. Bente Klitgaar (13:41):
I try and spoil it. But some indigenous tribes in
Northern Ecuador, they actually use one Brownea, a species of Brownea, grandiceps, as a contraceptive. And
I did lots of literature work. And I realized that
(14:01):
actually several species had been used by other indigenous tribes
in Colombia, in Venezuela, and in Ghana. So it's not,
it wasn't an isolated phenomenon. None of the families have
more than four children. The legume family members of the family, or members of the
legume family, it's been shown that they are the only
(14:23):
family to contain a group of chemicals called flavonoids, or
isoflavonoids. And these flavonoids or isoflavonoid, they've been found in a species of clover called trifolium
subterraneum. They have this estrogenic effect.
James Wong (14:40):
Having clues like this from naturally occurring compounds can get
scientists really excited, as it offers possible clues for building
affordable, safe, and sustainable alternatives for human use in a
lab. Bente explained why research like hers is so vital
in the first place.
Dr. Bente Klitgaar (14:59):
It has proved my viable. It has proved viable that you
found one compound in one plant that is protective against
cancer. And you can start to synthesize that part, but
you wouldn't have found that compound had you not found
it in a plant first.
James Wong (15:12):
And that covers everything from some of the most important
cancer drugs used in conventional medicine-
Dr. Bente Klitgaar (15:17):
Yeah, yeah.
James Wong (15:17):
... to the leading treatment for malaria.
Dr. Bente Klitgaar (15:20):
Exactly. Exactly.
James Wong (15:21):
So want to know is, did you ever write the
children's book?
Dr. Bente Klitgaar (15:28):
Unfortunately, I got very sidetracked by the science.
James Wong (15:32):
Thanks for listening to Unearthed. I'll be back again in
just a minute. But first here's a message from our
supporter, Kim Catrall.
Kim Catrall (15:41):
As a charity, the Royal Botanic Gardens, Kew is facing
a severe funding crisis right now. The impact of Coronavirus
has created a financial shortfall of 15 million pounds. This
money is vital for the upkeep of these beautiful botanic
gardens and crucial to continuing its global conservation work. Plants
(16:04):
and fungi hold many of the answers to the world's
biggest challenges, such as climate change, food security, and biodiversity
loss. And Kew needs to play a role in furthering
the science and identifying desperately needed solutions. If there's one
positive thing that could come out of this pandemic, it
(16:25):
will be to encourage each and every one of us
to look afresh and with urgency at these global challenges.
If you are enjoying this podcast, and feel inspired by
the work that Kew does, please go to Kew. org
to donate today, to help not only protect Kew, but
also preserve the future of our planet.
James Wong (16:49):
A really exciting area of Kew's modern day remit, lies
in the evaluation of plants. And this can mean traveling
far and wide to learn about new species, as well
as how they're being used by local people.
Tom Prescott (17:03):
I'm Tom Prescott, and my job title is Evaluation of
Plant Uses. I'm mainly focused on looking for potential medicines
from plants and fungi. So I first fell in love
with Papua New Guinea, kind of, I was working in
(17:24):
Australia and I decided to kind of go up there
and have a brief look. And then later on, when
I managed to start to get field work funding from
when I was an undergraduate, I started to go there.
People walk around barefoot and you have to. I'm quite
convinced of the idea actually, that if you live in
the rainforest permanently shoes are of very little value to you. And
(17:46):
the reason is that, just going about your day to
day business, walking across rainforest terrain, you need that sort
of tactile feedback from your feet. So for example, when
you're walking along, there's lots of deep ravines where the
little rivers at the bottom and you walk over essentially
tree trunks, from trees that have fallen over that act
(18:08):
like a bridge to walk across. But the downside is
if you get kind of scratched by something on your
ankle, in a rainforest environment, it gets infected really quickly.
James Wong (18:20):
After experiencing an infection himself, Tom became deeply interested in
how local plants were being used to treat them. Fortunately,
the antibacterial, or antimicrobial properties of some plants are there
to help tackle infections before they get serious.
Tom Prescott (18:36):
My interest is the plant medicines that are used to
treat these cutaneous ulcers, so skin ulcers, which are really
common there. They're quite debilitating, and because they go deep
into the tissue, they're really, really painful. There's a kind
of more serious side to it, which is that they
act as a possible gateway for secondary infections. So there's
(18:59):
another kind of bacterial infection caused by Treponema bacteria. And
it's sort of believed or theorized to be the case
that once you have one of these little skin ulcers,
that all the kids have gotten these villages, the Treponema
bacteria can then get into your body. And Treponema causes
something called Yaws Disease. And that that can have really
(19:23):
horrific consequences. It's not uncommon for plants to produce anti-
microbial substances. And then people who live in rainforests have
adapted to their environment, by learning which plants to use,
to put onto these infected skin ulcers. Eighty percent of
people in Papua New Guinea live in rural areas, and
(19:45):
when we say rural, we don't really mean people driving
around in Land Rovers in Devon. We mean people living
right out in really hard to access areas. The one
thing that a plant medicine has that can really win
over a conventional pharmaceutical treatment. And the one thing that
has that will basically beat the other treatment hands down
(20:07):
every time, is it exists in the field, and it's
constantly there.
James Wong (20:13):
Tom's fascination with local medicines available in the Papua New
Guinea rainforest led him to run trials, comparing how these anti-
microbial plant treatments with the sorts of things you can
buy over the counter in the UK. We had a
serious geek out about this. This is knowledge that people
in societies all over the world have potentially had for
(20:33):
decades, 100s, maybe even 1000s of years. But it's only
being reported scientifically now. And skin ulcers are something that
affects millions of people worldwide. So if there's an ability
to find a treatment for them, that is somehow more
effective, or either as effective as conventional therapies, then there's
(20:56):
some real massive potential benefit to humanity here. What have
we found so far?
Tom Prescott (21:01):
The most promising plant that we've been looking at is something
called Ficus septica, which is a species of tropical fig.
And also a crucial point here is that we're looking
for the most common anti- microbial plant that we can
find. The rationale is that we want to find clinical
(21:21):
evidence to support the use of a traditional medicine, but
the traditional medicine should be so common that anybody in
any village, virtually in lowland Papua New Guinea, you could just walk
50 yards and find this plant, and use it anytime
they want to. Ficus septica has really good antibacterial activity.
(21:43):
It produces lots and lots of little figs, sort of
like berry like things. And if you walk up to
Ficus septica, which is a small tree, and you can
find it kind of growing pretty much anywhere in lowland
Papua New Guinea, you pull off one of these little
fruit like things, and then this really beautiful white sap
starts dripping out of the end of the berry. And
(22:04):
the sap contains all these anti- microbial compounds. And what
you notice as it produces a slight sort of reddening around
where the sap has been, nothing too extreme, but as
if there's a little kind of immune response coming back,
which is quite interesting. But the other thing that the
plant sap does that we've seen really clearly is it
(22:25):
forms a kind of flexible plastic kind of covering over
the wound. There are flies that are attracted to these
wounds and they're believed to be transmitting bacteria. And I've
noticed this when I first had one of these infected
wounds, they make contact with the sap, it's almost like
they get a physical shock and they jump straight back,
and they won't go within a few millimeters of it.
James Wong (22:49):
So you have the anti- microbial response, which gets rid
of the infection, potentially it reduces your body's reaction to
that, the inflammation, which can cause a lot of pain.
It then seals the wound and also prevents secondary infection
from insects. That's nuts, like four different things all in
one plant.
Tom Prescott (23:08):
Yeah. I was pretty surprised to see all of this.
I think there is a lot more out there in the rain
forest that's waiting to be discovered.
James Wong (23:19):
It's so exciting to me to hear how the botanical
world is still offering new scientific surprises, and helping us
find solutions to old problems as we share knowledge around
the world. It makes you wonder what other undocumented answers
lie within the realms of our forests, hiding in plain
sight. From rainforest now to a forest of information. In
(23:44):
addition to Kew's living collections of medicinal plants, the economic
botany collection, or ECB, holds around 25, 000 items of medicinal plant
materials, including the Royal Pharmaceutical Society's collection of medicines, as
well as Chinese traditional medicines. I found out how we're
working with plants to make medicines today with Dr. Melanie-
(24:06):
Jayne Howes.
Dr. Melanie-Jayne Howes (24:10):
So my name is Melanie Howes. So I lead research
in phytochemistry and pharmacognosy at Kew. So much of my
research currently involves investigating the chemistry of plants, but especially
to understand their uses as medicines and also for our
health, such as in our diets.
James Wong (24:31):
It's very easy to assume that the uses of plants in
medicine is a historical anecdote. They were very interesting in
the past, in the Roman empire, but in modern pharmacology,
they're not used to the same extent. How accurate would
you think that common belief would be?
Dr. Melanie-Jayne Howes (24:48):
We have so many examples of pharmaceuticals, which were originally
discovered from plants. So some of these are the original
chemical that was derived from the plant itself. Some of
them are derivatives. And some of them, we use the
plant chemical to inspire us, to design a brand new
medicine. And we have many of these examples available in
(25:11):
clinical use currently. So for diseases such as dementia, cancer,
heart disease, malaria, and diabetes, we have many pharmaceuticals that
were originally inspired or provided by plants.
James Wong (25:26):
So we're not talking about things that are limited to
herbal medicines that you might buy in a alternative remedy
shop. We're talking about things that you'd get in a
regular pharmacy that would be prescribed on the NHS, for example.
Dr. Melanie-Jayne Howes (25:38):
Precisely. I mean, up until around sort of the early 19th century,
most people were using plants in the form of herbal
medicines. So these contain mixtures of many different plant compounds.
But then in the early 19th century, morphine was first
isolated from the opium poppy. And this completely revolutionized how
(26:01):
people used plants as medicine. Because for the first time,
we were, or humans were, isolating single chemicals from plants
and then developing these as a medicine. So this is
really the concept of the single active ingredient or the
pharmaceutical that we are familiar with in modern medicine today,
James Wong (26:22):
Opium and its derivatives are still used in modern medicine.
Dr. Melanie-Jayne Howes (26:26):
Absolutely. I mean, opium is a source of not only
morphine, but another analgesic, which was also discovered in the
1800s, which is codeine. And both of these are currently
in clinical use. And we still rely on the plant
to obtain these alkaloids. Because as humans, we can't synthesize
(26:47):
them easily from scratch in the laboratory. But morphine isn't
just used itself as an analgesic. It's actually inspired the
development of many other medicines. So this includes other analgesic
medicines to help with pain, but also for other types
of drugs, which are used for conditions such as coughs,
(27:07):
addiction, and also Parkinson's disease. But opium also contains a
completely different type of alkaloid chemical called Papaverine. Now this
has very different properties. So one of its effects is
that it can dilate blood vessels. So this compound was
used to inspire the design of a drug called Verapamil,
(27:32):
which is now in clinical use for certain heart conditions.
So the opium poppy has been very important in discovering
medicines, which we still find useful today. Plants are actually
brilliant chemists. The story of aspirin is actually a very
interesting story as a medicine, because it's discovery began in
(27:54):
the mid 1700s when the bark of the willow tree
was tested in people, and it seemed to be useful
to reduce fevers. But it wasn't until the next century
that it was discovered that the willow bark contains a
certain type of chemicals called salicylates. And these were found
(28:15):
to be the active ingredients of the willow bark. And
they were the inspiration for the developments of the drug
aspirin. But then it wasn't for another 80 years or
more, that scientists actually uncovered its mode of action. So
aspirin in the 1970s was found to inhibit the synthesis
(28:37):
of some inflammatory substances in the body called prostaglandins. But
its story doesn't end there. So even much later still,
aspirin was found to have another completely new role in
medicine. It was found to inhibit the aggregation of platelets
in the blood. So as a result, aspirin became used
(28:59):
more widely as a medicine to help reduce the risk
of blood clots in people that could be at risk
of certain heart conditions. So from the 1700s to the 1990s, we've
still been making discoveries about a widely used drug, originally
inspired by a plant.
James Wong (29:17):
So it isn't just about harnessing a chemical that instantly has
a therapeutic effect. It can be sometimes just using it as a
roadmap for inspiration. But the compounds found in plants can
be useful as an ingredient in which to create drugs after.
Dr. Melanie-Jayne Howes (29:32):
Absolutely. Yeah. Much of the research we've been doing in
recent years is looking at members of the mint family,
so the lamiaceae. So these are common herbs, which are
often used as part of our diet for flavoring food,
such as sage, rosemary, lemon balm, and mint. And we've
found some very interesting properties associated with these. We're really
(29:57):
scrutinizing their chemistry to find out which specific chemicals occur
in them and how they might have potential effects that
could be useful to our health. Particularly, if used as
part of our diet.
James Wong (30:08):
It's thought that up to 50% of medicinal plant species
will be extinct by the end of the century.
Dr. Melanie-Jayne Howes (30:14):
So it's absolutely critical that we can protect biodiversity. There
is now a shift to looking at plants, to use
them to inspire us, to discover new medicines rather than
exploit them.
James Wong (30:30):
It's so easy to dismiss plant- based medicines as merely
interesting historical anecdotes, a relic from another time. Yet 80%
of the human population still relies on compounds found in
plants as their primary form of healthcare. With at least
half of all of the most commonly prescribed pharmaceuticals being
(30:50):
originally derived from natural sources, unbeknownst to us, this includes
a large chunk of the stuff in our own medicine
cabinets. From local indigenous populations to international world- shaping cures,
plants have been essential to human health since the dawn
of humanity. And the reality is even today, we're still
(31:12):
just beginning to scratch the surface of their potential. Thanks
to breakthroughs in modern technology, we're able to travel further
and learn more about how we can demystify these properties
to make better lives for all. And none of this
would have been possible without working alongside the people who
live near and use those plants, being so generous with
(31:33):
their knowledge. These communities and the information they share, can
be absolutely vital to scientific discovery. Understanding the potential applications
of plants from people who've been using them for 100s,
if not 1000s of years has repeatedly proven to lead
to game changing medical discoveries. And there is so much
(31:55):
more to learn. To me, it's quite incredible to think
how much of our learning in this area has taken
place in the last few hundred years, a blink in
the eye, in the history of our species, making use
of the collection, knowledge and tools that we expand upon
every day. Now that this information is more available than
ever, our next challenge is how to create a sustainable
(32:18):
and respectful relationship between biodiversity and human progress to future
proof our planet for generations to come. The journey really
has only just begun. Next time on Unearthed from Kew.
Speaker 7 (32:35):
These leaf cutting ants, it'll make them climb towards the
light whilst the fungus finishes off the insides. And then
once it's finished eating it, it bursts out and produces
this little fruiting body. It's drawn out and horrible.
James Wong (32:50):
When did you last come in contact with mold, fungus,
and the like? Chances are you're doing it right now.
And your life's a lot better, thanks to this remarkable
kingdom. Next time I'll be delving into the forgotten world
of fungi, and finding out how little we still know
about one of the most important and mysterious elements of
(33:13):
life on earth. Plus, I'll hear about the surprising links
between psychedelic mushrooms and our mental health.
Speaker 8 (33:20):
About 15 years ago, we decided it was time to
explore the brain science of magic mushrooms. And I think
my claim to fame that I've probably given more different
kinds of drugs to human beings than anyone alive, but
the good news is they're all still alive too.
James Wong (33:39):
Make sure you don't miss it by subscribing on your
podcast app now. You can share this episode with a hashtag #
KewUnearthed and follow us at Kew Gardens on social media.
Join in the conversation with the hashtag # KewUnearthed. I am
James Wong. Thanks for listening.
December 7th, 1941, a surprise Japanese aerial attack on the
American Naval Base at Pearl Harbor in Hawaii initiated the
formal entry of the United States into the second World
War. Thousands were killed. The damage was extensive. In addition
(00:27):
to those that died that day, the Pearl Harbor attack
led to a far greater loss of life amongst the
Allied forces. Since the start of the war, malaria had
ravaged forces stationed in the West Indies. Only held at
Bay by a wonder drug from the Dutch East Indies
modern day, Indonesia. The source of this plantations of the
(00:50):
humble Cinchona tree on the Island of Java, where 90% of
the world's Quinine was sourced. Demand for this plant based
malaria cure roared during wartime. But by crippling the Allied
defense through the bombing of Pearl Harbor and the capturing
of Singapore, there was nothing to stop the Japanese from
(01:10):
taking Java and cutting off supplies to their enemies in
the West In the effort to acquire the island's rich
oil fields, Japan also denied its opponents one of the
most crucial medicines in human history, and scientists were forced
to seek out an alternative to the substance that had
enabled Western colonization of the tropics for centuries.
Kim Walker (01:34):
Cinchona has been called a tool of imperialism and that's
because Quinine, which is the active antimalarial chemical found in
the bark, was so important for empire, particularly across 18th and
19th century.
James Wong (01:48):
Today, we find out how plants and medicines have changed
the fortunes of nations, and their roots from forest to
pharmacy throughout history. We'll hear how the hunger for cures
has transformed landscapes, seen powers rise and fall, and altered
human history forever.
Kim Walker (02:07):
Quinine started to gain extra significance for them. So to
be able to control the quality and quantity of supply
became very important. Plantations started to be grown in British India and
Dutch Indonesia.
James Wong (02:19):
And we'll hear what we can learn and how lives
can be saved in the search for modern day medicines.
Dr. Melanie-Jayne Howes (02:25):
Plants are actually brilliant chemists.
James Wong (02:28):
I'm James Wong, and welcome to Unearth Mysteries from an
unseen world from Royal Botanic Gardens, Kew. Today, I'm finding
out how one kind of tree changed the course of
world history. The cinchona tree is native to South America.
(02:51):
Myth has it that in 1630, the Spanish Countess of Chinchon
visited Peru and fell ill with a fever. The substance
given to cure her was the bark of cinchona, which we now
know contains many useful substances, only one of which is
Quinine. And whilst the real story of how cinchona's healing
(03:12):
properties first made it into medicine, remains a mystery, there
are plenty of clues to help us piece together some
of that history. The Royal Botanic Gardens, Kew has one
of the largest collections of cinchona bark in addition to
Herbarium specimens and a wealth of historical records from the
19th century when Quinine was transported around the world. It's this
(03:36):
archive that makes Kew, so compelling for my first guest.
Kim Walker (03:40):
I'm Kim Walker, and I am a PhD student at
Kew. And I work in the Economic Botany Department and
I study that collection of cinchona bark. It does sound
a bit dry, doesn't it studying bark? But actually if
you're going to pick a bark, this is probably one
of the most interesting ones in history. Cinchona bark contains
Quinine which for over 300 years was the only known
(04:02):
malaria treatment in Europe. And also is the flavoring in
everybody's favorite cocktail, the gin and tonic, because it is
the flavoring and tonic water.
James Wong (04:11):
When we talk about malaria, it's quite difficult to picture a world
before cinchona bark was in existence, because malaria wasn't something that was just found in
remote location.
Kim Walker (04:21):
Yeah, absolutely. So it's just slightly out of living memory
now. So not many people realize that we used to have
malaria and Britain all the way up to the first World War.
James Wong (04:31):
So tell me about the history of cinchona bark. How
do we know that it contains Quinine and that that's
an effective treatment for malaria?
Kim Walker (04:39):
That's a really interesting question because when the Spanish entered South
America, which is where cinchona comes from originally, across the
Eastern slopes of the Andes, before this period, malaria, or
at least a very severe forms of malaria didn't exist.
So as the Spanish come in, bringing malaria with them,
and Cinchona trees already grow South America is not very
(05:00):
clear who or when somebody connected that cinchona bark kills
malaria. But it's likely that it would have been indigenous healers, had
really superior knowledge of local botanics and healing. And so
at the (inaudible) , as it were, where new diseases were
entering the country and cinchona may have already been in
use for other things, they would have put two and
(05:22):
two together and found the treatment. We do know that
was around about 1600. And by about the mid 1600s cinchona
bark started being imported into Europe.
James Wong (05:32):
Is this presumably because cinchona bark was really important for
industry at one point in time? People wouldn't be able to
conduct business across large parts of the world, if you
couldn't physically access them while staying healthy.
Kim Walker (05:45):
Absolutely. So cinchona has been called a tool of imperialism
and that's because Quinine, which is the active antimalarial chemical found
in the bark, was so important for empire, particularly across 18th and
19th century. And so, for many different countries within Europe
who are interested in expanding into new territories and colonizing
(06:08):
areas, such as India and parts of Africa, Quinine was
really important because unless you can control disease, whenever you
were to go somewhere that may have something like malaria,
you're more likely to die off than to be able to
enter those places.
James Wong (06:23):
How is Quintin traditionally administered? Was it administered in tonic water?
Kim Walker (06:27):
Tonic water came a little bit later in the 19th century,
which is about the mid 1800s. But originally how Europeans
started to use cinchona was in very traditional ways to
use medicine, which is getting the bark, which is a
very tough material, grinding up into a powder. So you
can crack open all the plant cells and get the
chemicals out, and then dilute it. And the best way
(06:49):
to dilute and extract chemicals quite often is by using
a bit of alcohol. So early ways to dilute it
would have been using wine, or port, or perhaps stronger
spirits like brandy. By the 19th century, it was one of
the largest imports of American drugs imported to Europe. Demand
(07:09):
started to outstrip supply, and it started to be over
harvested in the world by some unscrupulous harvesters. And as this
happened, and as the 19th century grew older and different
empire started to look further afield to colonize new areas,
Quinine started to gain extra significance for them. Around the
early 1900s, different countries, particularly the Dutch and the British,
(07:33):
started to look into how they could get hold of
this tree for themselves to cultivate. Quinine was used all
the way up to the second World War, when supplies
from Indonesian plantations got caught off. Unfortunately, using Quinine to
control the ability to colonize the areas is not a very
(07:53):
nice thing to think about. And for the British and the
Dutch to get hold of these trees, they were going
to have to basically smuggle them out of South America.
And they were justifying that as saving the seeds because
of over harvesting, which is very complicated, because really nowadays
you wouldn't do that. You would work with communities to
bring up the cinchona bark and make it available for
(08:14):
everybody if they chose to. Everything was different then. And
unfortunately, they smuggled out to make plantations in India and Indonesia.
James Wong (08:23):
So in that time, that was really considered par for the core.
So people wouldn't have raised an eyebrow at all about
the idea of taking plant material for one part of
the world, or taking the knowledge of plant material even,
and applying it for themselves. But nowadays we actually have
a term for that bio- piracy and the same way
that you would pirate a bootleg CD or a copy
(08:46):
of a film that you download off the internet. We
would have the same term for biological genetic information, and
also information about how to grow and use plants. Now
I should just point out here that Kim's book, Just
the Tonic a Natural History of Tonic Water, which she co-
wrote with Mark Nesbitt, is a fantastic read. If you'd
(09:08):
like to delve a little deeper into the rich history of
this favorite tipple, then check it out. The Cinchona story
is just one example of how a naturally occurring medicine
played an essential role in the movement of people internationally.
With the current conversation about the British empire and its
legacy, it's fascinating to me to contemplate whether European powers
(09:31):
would have been able to colonize the world's tropical regions
to the same extent, if at all, without this wonder
drug. Or would history have unfolded quite differently? It's amazing
to think that this humble tree might have carried the
course of history upon its delicate branches. Nowadays, scientists are
investigating new substances that can be created using other alkaloids
(09:54):
within cinchona bark. And while science is opening more doors
to plant medicines every day, they are still a constant
source of novel, unexpected compounds. I chatted to Dr. Bente
Klitgaar, Senior Research Leader in Identification and Naming and Head
of the Americas Department at Kew. She's mostly based in
(10:15):
the Herbarium where seven million plant specimens are held. Her
team looks after the two million of them from the
Americas. My first visit to Kew's Herbarium was 15 years ago
now, and I was just starting on my master's. And
it's quite difficult to picture what seven million samples is
like. But to me, it was like going into a
scene from Harry Potter, just floor after floor in this
(10:38):
beautiful old Victorian building, of course, with some modern adjuncts
now. And a Herbarium is to an untrained eye, just
millions of pressed flower specimens.
Dr. Bente Klitgaar (10:48):
They are.
James Wong (10:49):
It's like some kind of someone's hobby just went really
out of control. Why is it important to have so
many just pieces of plant squished between paper?
Dr. Bente Klitgaar (11:00):
They are the ultimate evidence. Because we don't just have
one of each plant species, we have about 80% of
the biodiversity in terms of the generic level, which is
a bit scientific, represented in Kew's Herbarium. So, Kew's Herbarium is one of
the best global collections in the world. And as I said, we can use it for any type
(11:22):
of research, because we don't have to have all one
of each species, we have the whole distribution range. I have
some plants that I have known ever since I started
my career in botany. And these are the legume family that I have been
specializing. I've been doing many things in my career, but
the legume family has always been part, been my friend all
(11:43):
the way along.
James Wong (11:44):
So peas and beans, the legume family. It's such a massive
family. And this includes everything from tiny little herbs in
the Arctic Tundra-
Dr. Bente Klitgaar (11:50):
Exactly, yes.
James Wong (11:50):
... right up to giant Amazonian trees.
Dr. Bente Klitgaar (11:53):
Yes. Some of the biggest emergence in the Amazon are
legumes as well. So I'm going to show you some of
my very, very best friends and my first legume friend.
It's a genus called Brownea. When I started working on
this genus called Brownea, they're rainforest trees. They occur only
in Northwestern, South America. And I can show you-
James Wong (12:13):
Wow, look at that.
Dr. Bente Klitgaar (12:16):
Yeah. Yeah. So, at Key, we are very, very lucky.
There's one in the Palm house, which is Brownea Coccinia,
and there's one at Princess or Wales Conservatory called Brownea grandiceps.
So when I miss them, I can go into one
of these green houses, and they flower as well, they're fantastic. They get up about a football size.
James Wong (12:40):
It looks like something straight out of the movie Avatar.
It's like a giant pompom flower with these really, really
long filaments that are coming out of it.
Dr. Bente Klitgaar (12:48):
Yeah.
James Wong (12:48):
Almost like you've got a big fistful of the showiest
rhododendron and stuck them all together-
Dr. Bente Klitgaar (12:52):
Exactly.
James Wong (12:52):
... and just made them look even more exotic.
Dr. Bente Klitgaar (12:56):
As a young scientist, I decided to work on this
group for my Master's thesis. So I went then and my task was
to understand that the Brownea is species in Ecuador. That was one
task, and the other task was then to understand how the Brownea species
were used in Ecuador. And I wanted to write a book about
(13:18):
children who live in the rainforest. So I actually got
myself a deal with a publisher. And I went and visited
some indigenous communities in the Amazon at the same time.
So I realized-
James Wong (13:35):
Talk about multitasking there. Is there anything you can't do?
Dr. Bente Klitgaar (13:41):
I try and spoil it. But some indigenous tribes in
Northern Ecuador, they actually use one Brownea, a species of Brownea, grandiceps, as a contraceptive. And
I did lots of literature work. And I realized that
(14:01):
actually several species had been used by other indigenous tribes
in Colombia, in Venezuela, and in Ghana. So it's not,
it wasn't an isolated phenomenon. None of the families have
more than four children. The legume family members of the family, or members of the
legume family, it's been shown that they are the only
(14:23):
family to contain a group of chemicals called flavonoids, or
isoflavonoids. And these flavonoids or isoflavonoid, they've been found in a species of clover called trifolium
subterraneum. They have this estrogenic effect.
James Wong (14:40):
Having clues like this from naturally occurring compounds can get
scientists really excited, as it offers possible clues for building
affordable, safe, and sustainable alternatives for human use in a
lab. Bente explained why research like hers is so vital
in the first place.
Dr. Bente Klitgaar (14:59):
It has proved my viable. It has proved viable that you
found one compound in one plant that is protective against
cancer. And you can start to synthesize that part, but
you wouldn't have found that compound had you not found
it in a plant first.
James Wong (15:12):
And that covers everything from some of the most important
cancer drugs used in conventional medicine-
Dr. Bente Klitgaar (15:17):
Yeah, yeah.
James Wong (15:17):
... to the leading treatment for malaria.
Dr. Bente Klitgaar (15:20):
Exactly. Exactly.
James Wong (15:21):
So want to know is, did you ever write the
children's book?
Dr. Bente Klitgaar (15:28):
Unfortunately, I got very sidetracked by the science.
James Wong (15:32):
Thanks for listening to Unearthed. I'll be back again in
just a minute. But first here's a message from our
supporter, Kim Catrall.
Kim Catrall (15:41):
As a charity, the Royal Botanic Gardens, Kew is facing
a severe funding crisis right now. The impact of Coronavirus
has created a financial shortfall of 15 million pounds. This
money is vital for the upkeep of these beautiful botanic
gardens and crucial to continuing its global conservation work. Plants
(16:04):
and fungi hold many of the answers to the world's
biggest challenges, such as climate change, food security, and biodiversity
loss. And Kew needs to play a role in furthering
the science and identifying desperately needed solutions. If there's one
positive thing that could come out of this pandemic, it
(16:25):
will be to encourage each and every one of us
to look afresh and with urgency at these global challenges.
If you are enjoying this podcast, and feel inspired by
the work that Kew does, please go to Kew. org
to donate today, to help not only protect Kew, but
also preserve the future of our planet.
James Wong (16:49):
A really exciting area of Kew's modern day remit, lies
in the evaluation of plants. And this can mean traveling
far and wide to learn about new species, as well
as how they're being used by local people.
Tom Prescott (17:03):
I'm Tom Prescott, and my job title is Evaluation of
Plant Uses. I'm mainly focused on looking for potential medicines
from plants and fungi. So I first fell in love
with Papua New Guinea, kind of, I was working in
(17:24):
Australia and I decided to kind of go up there
and have a brief look. And then later on, when
I managed to start to get field work funding from
when I was an undergraduate, I started to go there.
People walk around barefoot and you have to. I'm quite
convinced of the idea actually, that if you live in
the rainforest permanently shoes are of very little value to you. And
(17:46):
the reason is that, just going about your day to
day business, walking across rainforest terrain, you need that sort
of tactile feedback from your feet. So for example, when
you're walking along, there's lots of deep ravines where the
little rivers at the bottom and you walk over essentially
tree trunks, from trees that have fallen over that act
(18:08):
like a bridge to walk across. But the downside is
if you get kind of scratched by something on your
ankle, in a rainforest environment, it gets infected really quickly.
James Wong (18:20):
After experiencing an infection himself, Tom became deeply interested in
how local plants were being used to treat them. Fortunately,
the antibacterial, or antimicrobial properties of some plants are there
to help tackle infections before they get serious.
Tom Prescott (18:36):
My interest is the plant medicines that are used to
treat these cutaneous ulcers, so skin ulcers, which are really
common there. They're quite debilitating, and because they go deep
into the tissue, they're really, really painful. There's a kind
of more serious side to it, which is that they
act as a possible gateway for secondary infections. So there's
(18:59):
another kind of bacterial infection caused by Treponema bacteria. And
it's sort of believed or theorized to be the case
that once you have one of these little skin ulcers,
that all the kids have gotten these villages, the Treponema
bacteria can then get into your body. And Treponema causes
something called Yaws Disease. And that that can have really
(19:23):
horrific consequences. It's not uncommon for plants to produce anti-
microbial substances. And then people who live in rainforests have
adapted to their environment, by learning which plants to use,
to put onto these infected skin ulcers. Eighty percent of
people in Papua New Guinea live in rural areas, and
(19:45):
when we say rural, we don't really mean people driving
around in Land Rovers in Devon. We mean people living
right out in really hard to access areas. The one
thing that a plant medicine has that can really win
over a conventional pharmaceutical treatment. And the one thing that
has that will basically beat the other treatment hands down
(20:07):
every time, is it exists in the field, and it's
constantly there.
James Wong (20:13):
Tom's fascination with local medicines available in the Papua New
Guinea rainforest led him to run trials, comparing how these anti-
microbial plant treatments with the sorts of things you can
buy over the counter in the UK. We had a
serious geek out about this. This is knowledge that people
in societies all over the world have potentially had for
(20:33):
decades, 100s, maybe even 1000s of years. But it's only
being reported scientifically now. And skin ulcers are something that
affects millions of people worldwide. So if there's an ability
to find a treatment for them, that is somehow more
effective, or either as effective as conventional therapies, then there's
(20:56):
some real massive potential benefit to humanity here. What have
we found so far?
Tom Prescott (21:01):
The most promising plant that we've been looking at is something
called Ficus septica, which is a species of tropical fig.
And also a crucial point here is that we're looking
for the most common anti- microbial plant that we can
find. The rationale is that we want to find clinical
(21:21):
evidence to support the use of a traditional medicine, but
the traditional medicine should be so common that anybody in
any village, virtually in lowland Papua New Guinea, you could just walk
50 yards and find this plant, and use it anytime
they want to. Ficus septica has really good antibacterial activity.
(21:43):
It produces lots and lots of little figs, sort of
like berry like things. And if you walk up to
Ficus septica, which is a small tree, and you can
find it kind of growing pretty much anywhere in lowland
Papua New Guinea, you pull off one of these little
fruit like things, and then this really beautiful white sap
starts dripping out of the end of the berry. And
(22:04):
the sap contains all these anti- microbial compounds. And what
you notice as it produces a slight sort of reddening around
where the sap has been, nothing too extreme, but as
if there's a little kind of immune response coming back,
which is quite interesting. But the other thing that the
plant sap does that we've seen really clearly is it
(22:25):
forms a kind of flexible plastic kind of covering over
the wound. There are flies that are attracted to these
wounds and they're believed to be transmitting bacteria. And I've
noticed this when I first had one of these infected
wounds, they make contact with the sap, it's almost like
they get a physical shock and they jump straight back,
and they won't go within a few millimeters of it.
James Wong (22:49):
So you have the anti- microbial response, which gets rid
of the infection, potentially it reduces your body's reaction to
that, the inflammation, which can cause a lot of pain.
It then seals the wound and also prevents secondary infection
from insects. That's nuts, like four different things all in
one plant.
Tom Prescott (23:08):
Yeah. I was pretty surprised to see all of this.
I think there is a lot more out there in the rain
forest that's waiting to be discovered.
James Wong (23:19):
It's so exciting to me to hear how the botanical
world is still offering new scientific surprises, and helping us
find solutions to old problems as we share knowledge around
the world. It makes you wonder what other undocumented answers
lie within the realms of our forests, hiding in plain
sight. From rainforest now to a forest of information. In
(23:44):
addition to Kew's living collections of medicinal plants, the economic
botany collection, or ECB, holds around 25, 000 items of medicinal plant
materials, including the Royal Pharmaceutical Society's collection of medicines, as
well as Chinese traditional medicines. I found out how we're
working with plants to make medicines today with Dr. Melanie-
(24:06):
Jayne Howes.
Dr. Melanie-Jayne Howes (24:10):
So my name is Melanie Howes. So I lead research
in phytochemistry and pharmacognosy at Kew. So much of my
research currently involves investigating the chemistry of plants, but especially
to understand their uses as medicines and also for our
health, such as in our diets.
James Wong (24:31):
It's very easy to assume that the uses of plants in
medicine is a historical anecdote. They were very interesting in
the past, in the Roman empire, but in modern pharmacology,
they're not used to the same extent. How accurate would
you think that common belief would be?
Dr. Melanie-Jayne Howes (24:48):
We have so many examples of pharmaceuticals, which were originally
discovered from plants. So some of these are the original
chemical that was derived from the plant itself. Some of
them are derivatives. And some of them, we use the
plant chemical to inspire us, to design a brand new
medicine. And we have many of these examples available in
(25:11):
clinical use currently. So for diseases such as dementia, cancer,
heart disease, malaria, and diabetes, we have many pharmaceuticals that
were originally inspired or provided by plants.
James Wong (25:26):
So we're not talking about things that are limited to
herbal medicines that you might buy in a alternative remedy
shop. We're talking about things that you'd get in a
regular pharmacy that would be prescribed on the NHS, for example.
Dr. Melanie-Jayne Howes (25:38):
Precisely. I mean, up until around sort of the early 19th century,
most people were using plants in the form of herbal
medicines. So these contain mixtures of many different plant compounds.
But then in the early 19th century, morphine was first
isolated from the opium poppy. And this completely revolutionized how
(26:01):
people used plants as medicine. Because for the first time,
we were, or humans were, isolating single chemicals from plants
and then developing these as a medicine. So this is
really the concept of the single active ingredient or the
pharmaceutical that we are familiar with in modern medicine today,
James Wong (26:22):
Opium and its derivatives are still used in modern medicine.
Dr. Melanie-Jayne Howes (26:26):
Absolutely. I mean, opium is a source of not only
morphine, but another analgesic, which was also discovered in the
1800s, which is codeine. And both of these are currently
in clinical use. And we still rely on the plant
to obtain these alkaloids. Because as humans, we can't synthesize
(26:47):
them easily from scratch in the laboratory. But morphine isn't
just used itself as an analgesic. It's actually inspired the
development of many other medicines. So this includes other analgesic
medicines to help with pain, but also for other types
of drugs, which are used for conditions such as coughs,
(27:07):
addiction, and also Parkinson's disease. But opium also contains a
completely different type of alkaloid chemical called Papaverine. Now this
has very different properties. So one of its effects is
that it can dilate blood vessels. So this compound was
used to inspire the design of a drug called Verapamil,
(27:32):
which is now in clinical use for certain heart conditions.
So the opium poppy has been very important in discovering
medicines, which we still find useful today. Plants are actually
brilliant chemists. The story of aspirin is actually a very
interesting story as a medicine, because it's discovery began in
(27:54):
the mid 1700s when the bark of the willow tree
was tested in people, and it seemed to be useful
to reduce fevers. But it wasn't until the next century
that it was discovered that the willow bark contains a
certain type of chemicals called salicylates. And these were found
(28:15):
to be the active ingredients of the willow bark. And
they were the inspiration for the developments of the drug
aspirin. But then it wasn't for another 80 years or
more, that scientists actually uncovered its mode of action. So
aspirin in the 1970s was found to inhibit the synthesis
(28:37):
of some inflammatory substances in the body called prostaglandins. But
its story doesn't end there. So even much later still,
aspirin was found to have another completely new role in
medicine. It was found to inhibit the aggregation of platelets
in the blood. So as a result, aspirin became used
(28:59):
more widely as a medicine to help reduce the risk
of blood clots in people that could be at risk
of certain heart conditions. So from the 1700s to the 1990s, we've
still been making discoveries about a widely used drug, originally
inspired by a plant.
James Wong (29:17):
So it isn't just about harnessing a chemical that instantly has
a therapeutic effect. It can be sometimes just using it as a
roadmap for inspiration. But the compounds found in plants can
be useful as an ingredient in which to create drugs after.
Dr. Melanie-Jayne Howes (29:32):
Absolutely. Yeah. Much of the research we've been doing in
recent years is looking at members of the mint family,
so the lamiaceae. So these are common herbs, which are
often used as part of our diet for flavoring food,
such as sage, rosemary, lemon balm, and mint. And we've
found some very interesting properties associated with these. We're really
(29:57):
scrutinizing their chemistry to find out which specific chemicals occur
in them and how they might have potential effects that
could be useful to our health. Particularly, if used as
part of our diet.
James Wong (30:08):
It's thought that up to 50% of medicinal plant species
will be extinct by the end of the century.
Dr. Melanie-Jayne Howes (30:14):
So it's absolutely critical that we can protect biodiversity. There
is now a shift to looking at plants, to use
them to inspire us, to discover new medicines rather than
exploit them.
James Wong (30:30):
It's so easy to dismiss plant- based medicines as merely
interesting historical anecdotes, a relic from another time. Yet 80%
of the human population still relies on compounds found in
plants as their primary form of healthcare. With at least
half of all of the most commonly prescribed pharmaceuticals being
(30:50):
originally derived from natural sources, unbeknownst to us, this includes
a large chunk of the stuff in our own medicine
cabinets. From local indigenous populations to international world- shaping cures,
plants have been essential to human health since the dawn
of humanity. And the reality is even today, we're still
(31:12):
just beginning to scratch the surface of their potential. Thanks
to breakthroughs in modern technology, we're able to travel further
and learn more about how we can demystify these properties
to make better lives for all. And none of this
would have been possible without working alongside the people who
live near and use those plants, being so generous with
(31:33):
their knowledge. These communities and the information they share, can
be absolutely vital to scientific discovery. Understanding the potential applications
of plants from people who've been using them for 100s,
if not 1000s of years has repeatedly proven to lead
to game changing medical discoveries. And there is so much
(31:55):
more to learn. To me, it's quite incredible to think
how much of our learning in this area has taken
place in the last few hundred years, a blink in
the eye, in the history of our species, making use
of the collection, knowledge and tools that we expand upon
every day. Now that this information is more available than
ever, our next challenge is how to create a sustainable
(32:18):
and respectful relationship between biodiversity and human progress to future
proof our planet for generations to come. The journey really
has only just begun. Next time on Unearthed from Kew.
Speaker 7 (32:35):
These leaf cutting ants, it'll make them climb towards the
light whilst the fungus finishes off the insides. And then
once it's finished eating it, it bursts out and produces
this little fruiting body. It's drawn out and horrible.
James Wong (32:50):
When did you last come in contact with mold, fungus,
and the like? Chances are you're doing it right now.
And your life's a lot better, thanks to this remarkable
kingdom. Next time I'll be delving into the forgotten world
of fungi, and finding out how little we still know
about one of the most important and mysterious elements of
(33:13):
life on earth. Plus, I'll hear about the surprising links
between psychedelic mushrooms and our mental health.
Speaker 8 (33:20):
About 15 years ago, we decided it was time to
explore the brain science of magic mushrooms. And I think
my claim to fame that I've probably given more different
kinds of drugs to human beings than anyone alive, but
the good news is they're all still alive too.
James Wong (33:39):
Make sure you don't miss it by subscribing on your
podcast app now. You can share this episode with a hashtag #
KewUnearthed and follow us at Kew Gardens on social media.
Join in the conversation with the hashtag # KewUnearthed. I am
James Wong. Thanks for listening.
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