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 heterophylly. What do I mean by heterophylly? 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 lot of plants. We don't realize how valuable and how precious these resources are, and yet, through our insouciance, we keep on destroying them. 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, of course, we know is now a symbol of extinction.
We know plants have a fundamental role to play. Well, first of all, they feed 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 human societies over the millennia, 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 is home to 40 percent of the species of higher plants, 35 percent of the species of vertebrates, and this 1.4 percent represents the 25 biodiversity hotspots in the world, and this 1.4 percent of the entire land surface already provides 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, of course, 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 that 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'ile 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 has shown that precisely these leaves contain ingredients that are very close, 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. The monkeys 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 protein, more protein than 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 reinforced 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 is 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 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, 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 inexperienced gardener, the first thing you'll do when you visit the garden is to uproot this plant because 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 slow 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. 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 in 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 are 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 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.