Humble plants that hide surprising secrets

You know, it's a big privilege for me

to be working in one of the
biodiversity hotspots in the world:

the Mascarene Islands in the Indian Ocean.

These islands — Mauritius,
Rodrigues, and Réunion —

along with the island of Madagascar,

they are blessed with unique plants

found nowhere else in the world.

And today I will tell you about five of them

and their particular features

and why these plants are so unique.

Take a look at this plant.

I call it "Benjoin" in the local vernacular,

and the botanical name is terminalia bentzoe,

subspecies bentzoe.

This subspecies is endemic to Mauritius,

and its particular feature

is its heterofelicity.

What do I mean by heterofelicity?

It's that the same plant

has got leaves that are different shapes and sizes.

Now, these plants have evolved

very far away from the mainland,

and within specific ecosystems.

Often, these particular features

have evolved as a response to the threat

presented by the local fauna,

in this case, grazing tortoises.

Tortoises are known to have poor eyesight,

and as such, they tend to avoid the plants

they don't recognize.

So this evolutionary foil safeguards the plant

against these rather cute animals,

and protects it and of course ensures its survival.

Now the question you're probably asking yourself is,

why is she telling us all these stories?

The reason for that is that we tend to overlook

the diversity and the variety of the natural world.

These particular habitats are unique

and they are host to a whole [???] of plants.

We don't realize how valuable

and how precious these resources are,

and yet, through our insouciance,

we keep on destroying them.

You know, we're all familiar

with the macro impact of urbanization,

climate change, resource exploitation,

but when that one last plant,

or animal for that matter,

when that very last specimen

has disappeared from the face of this Earth,

we would have lost

an entire subset of the Earth's biology,

and with it, important plants with medicinal potential

or which could have ingredients

that would speak to the cosmetic,

nutrition, pharma,

and even the ethno-veterinary sectors,

be gone forever.

And here we have a very prime example

of the iconic dodo, which comes from Mauritius,

and which we know is now a symbol of extinction.

And we know plants have a fundamental role to play.

Well first of all, it feeds us,

and they also give us the oxygen we breathe,

but plants are also the source

of important, biologically active ingredients

that we should be studying very carefully,

because you know, human societies over the millenia

they have developed important knowledge,

cultural traditions,

and important plant-based medicinal resources.

Here's a data point:

1.4 percent of the entire land surface

are home to 40 percent of
the species of higher plants,

35 percent of the species of vertebrates,

and these 1.4 percent

represent the 25 biodiversity hotspots in the world,

and this 1.4 percent of the entire land surface

already provide for 35 percent

of the ecosystem services

that vulnerable people depend on.

And as you can see,

the island of Mauritius

where I work and where I live,

belongs to one such biodiversity hotspot,

and I study the unique plants

on the island for their biomedical applications.

Now, let's go back again

to that first plant I showed you,

the one with different-shaped leaves

and different sizes, terminalia bentzoe,

subspecies bentzoe,

a plant only found in Mauritius.

Now, the local people,

they used a decoction of the leaves

against infectious diseases.

Now, our work that is

the scientific validation of this traditional information

has shown that precisely

the leaf extract shows activity, potent activity,

against a wide range of bacteria

that could be pathogenic to humans.

Now, could this plant be the answer

to antibiotic resistance?

You know, antibiotic resistance is proving to be

a big challenge globally.

While we may not be sure, one thing is certain:

we will not want this plant to disappear.

But the harsh reality is that

this particular plant is in fact

considered to be vulnerable

in its natural habitat.

This brings me to another example.

This bush here is known as baume de l'isle plate

in the local vernacular.

The botanical name is psiadia arguta.

It's a plant which is rare,

which is endemic to Mauritius.

It used to grow on the mainland,

but through the sheer pressures of urbanization

has been pushed out of the mainland,

and we've managed to bring it back

from the brink of extinction

by developing in vitro plants

which are now growing in the wild.

Now, one thing I must point out straightaway

is that not all plants

can be developed in vitro.

While we humans, we are happy in our comfort zone,

these plants also need

their ecosystem to be preserved,

and they don't react, endemic plants

don't react to very harsh changes in their ecosystem,

and yet we know, what are the challenges

that climate change, for example,

is posing to these plants.

Now, the local people again use the leaves

in traditional medicine

against respiratory problems.

Now, our preliminary labwork

on the leaf extract have shown

that precisely these leaves contain ingredients

that are very closely, in terms of structures,

chemical structures, to those medicines

which are sold in the chemist's shop

against asthma.

So who knows

what humanity will benefit from

should this plant decide to reveal all its secrets.

Now, I come from the developing world

where we are forever being challenged with this issue

of population explosion.

Africa is the continent which is getting younger,

and whenever one talks about population explosion,

one talks about the issue of food security

as being the other side of the same coin.

Now this plant here, the baobab,

could be part of the answer.

It's an underutilized, neglected food plant.

It defines the landscape of West Africa,

where it is known as the tree of life,

and later on I will tell you why

the Africans consider it to be the tree of life.

Now interestingly, there are many legends

which are associated with this plant.

Because of its sheer size,

it was meant to be lording over lesser plants,

so God didn't like this arrogance,

uprooted it, and planted it upside down,

hence its particular shape.

And if you look at this tree again

within the African context,

in West Africa, it's known as the palaver tree,

because it performs great social functions.

Now if you have a problem in the community,

meeting under the palaver tree

with the chiefs or the tribesmen

would be synonymous to trying to find a solution

to that particular problem,

and also to reinforce trust and respect

among members of the community.

From the scientific point of view,

there are eight species of baobab in the world.

There's one from Africa,

one from Australia,

and six are endemic

to the island of Madagascar.

The one I have showed you

is the one from Africa,

adansonia digitata.

Now, the flower, this beautiful white flower,

it opens at night, is pollinated by bats,

and it gives rise to the fruit

which is curiously known

as the monkey apple.

You know, the monkey are not stupid animals.

They know what's good for them.

Now, if you open the fruit of the baobab,

you'll see a white, floury pulp

which is very rich in nutrients

and has got proteins,

more proteins than that in human milk.

Yes, you heard right:

more protein than in human milk.

And this is one of the reasons why

the nutrition companies of this world,

they are looking for this fruit to provide

what we know as reinforce food.

The seeds give an oil, a very stable oil

which is sought after by the cosmetic industry

to give to produce body lotions for example,

and if you look at the trunk,

the trunk of course safeguards water,

which is often harvested by a thirsty traveler,

and the leaves are used in traditional medicine

against infectious disease.

Now, you can see now why the Africans consider it

to be the tree of life.

It's a complete plant,

and in fact, the sheer size of these trees,

in fact, are hiding a massive potential,

not only for the pharma, nutrition,
and the cosmetic industry.

What I have showed you here

is only the species from Africa,

adansonia digitata.

We have six species yet in Madagascar,

and we don't know what is the potential of this plant,

but one thing we know is that the flora

is considered to be threatened with extinction.

Let me again take you to Africa again,

and introduce you to one of my very favorite,

the resurrection plant.

Now here you'll find

that even Jesus has competition.

(Laughter)

Now, this plant here has developed

remarkable tolerance to drought,

which enables it to withstand

up to 98 percent dehydration over the period of a year

without damage,

and yet it can regenerate itself almost completely

overnight, over 24 hours, and flower.

Now, us human beings, you know,

we're always on the lookout for the elixir of youth.

We don't want to get old, and rightly so.

Why should we, especially if you can afford it?

And this gives you an indication

of what the plant looks like before.

Now, if you are an unexperienced gardener,

the first thing you'll do when you visit the garden

is to uproot this plant, because, I mean, it's dead,

but if you water it, this is what you get.

Absolutely amazing.

Now, if you look at our aging process,

the aging process is in fact the loss of water

from the upper epidermis, resulting in wrinkling

as we know it, especially women,

we are so conscious of this,

and this plant, in fact, is giving the cosmetic chemists

very important ingredients

that are actually finding ways

to slowing down the aging process

and at the same time reinforce the cells

against the onslaught of environmental toxins.

Now, these four examples

I have just given you

are just a very tiny reminder

as to how our health

and our survival are closely linked

to the health and the resilience

of our ecosystem,

and why we should be very careful

about preserving biodiversity.

Every time a forest is cut down,

every time a marsh is filled in,

it is a potential lab that goes with it,

and which we will never, ever recover.

And I know what I'm talking about

coming from Mauritius and missing the dodo.

Let me finish with just one last example.

You know conservation issues are normally guided

towards rare, endemic plants,

but what we call exotic plants,

that is the ones which grow in many
different habitats across the world,

they also need to be considered.

You know why? Because the environment plays

a very important role

on modifying the composition of that plant.

So let's take a look at this plant here,

centella asiatica. It's a weed.

We call it a weed.

Now, centella asiatica grows across the world

in many different habitats, in Africa, in Asia,

and this plant has been instrumental

in providing a solution to that dreadful disease

called leprosy in Madagascar in the 1940s.

Now, while centella grows across the world,

in Africa, in Asia, the best quality centella

comes from Madagascar,

because that centella contains
the three vital ingredients

which are sought after by the pharma

and the cosmetic companies.

And the cosmetic companies is already using it

to make regenerating cream.

Now, there is an ancient saying

that for every disease known to mankind,

there is a plant to cure it.

Now, you may not believe in ancient sayings.

You may think they're obsolete

now that our science and technology are so powerful.

So, I mean, you may look on centella as being

an insignificant, humble weed,

which if destroyed won't be missed.

But you know, there is no such thing as a weed.

It's a plant.

It's a living biological lab

that may well have answers

to the question that we may have

but we have to ensure

that it has the right to live.

Thank you.

(Applause)