NATURE’S MEDICINE CABINET
We last saw James Crewdson in the woods hugging trees and saying “Yeah man, nature’s got, like, all the healing power you need, dude!” Perhaps he’s become a bit carried away with his search to discover nature’s hidden medicines. Join his expedition on page 25.
For as long as there has been disease, people have looked to nature to find cures for their ills. Whether it was Aztec doctors using tree roots to cure stomach aches or ancient Chinese practitioners using seahorses to cure kidney problems, the natural world has always offered doctors plenty to put in their medicine bag. Today, even in cutting-edge research facilities, the outdoor laboratory of nature is still a goldmine for important drugs. Let us now go on a journey into the wild – to discover nature’s hidden healers…
A walk in the scrublands
If you happened to be strolling through the scrublands of south-western America on a spring morning, you might be lucky enough to meet a two foot (60cm) long lizard called a glia monster. This venomous lizard is an ugly beast but it’s not dangerous. (It’s too slow-moving to catch a human.) Its saliva, however, contains substances that have the power to fight disease. Move over Harry Potter fans, this dragon spit is for real: Glia monster saliva contains a substance called exendin-4, a compound that can be used to treat diabetes. This chemical is very similar to a hormone ( GLP-1) released in humans when food is broken down. It has been used to produce the diabetes drug exenatide – a modern medicine that causes weight loss and helps control insulin blood levels. But the healing slobber of this remarkable lizard doesn’t end there. It also contains gilatide, a chemical which appears to boost memory and may one day be used to treat Alzheimer’s disease.
Relaxing by the river
As we continue our journey, we saunter along an English riverbank in June. The willow tree is there, in all its green splendour. In the bark of this majestic tree, there is a chemical called salicylic acid, the main component of a chemical best known to us as aspirin. This is one of the most important drugs available today, and is used in pain relief and stroke prevention. Sometimes the oldest remedies are the best: every year over 100 billion aspirin tablets are swallowed. Aspirin was made into medicine in 1897 but plants have also made more recent contributions too – although to discover these we must
travel further afield.
A trip to the tropics
You would probably ask for a second opinion if your doctor gave you some Madagascan rosy periwinkle, but this plant has made a huge contribution towards the treatment of childhood leukaemia. With pretty pink flowers, it is a short shrub that grows in the rainforest. You wouldn’t have to travel far to spot it: the plant is known for its beauty and is used as an ornamental plant the world over. And it is certainly worthy of prominence: vinblastine, which is extracted from its leaves, has increased the survival rates of childhood leukaemia from 10% to around 95%.
High and low, grubby and clean
It’s not just plants and animals that have health benefits – fungi also get in on the act. Fungi are amazingly diverse organisms and can survive in places where few other living things can. Some live in deep sea sediments, withstanding extremely high pressures, while others live in areas of high temperature or salt concentrations. To live in such a wide range of habitats, they have become mini-chemical factories, which is extremely useful for humans. The shining jewels in the crown of fungal contributions to medicine are antibiotics. From the untidy mess of Sir Alexander Fleming’s lab came an accidental discovery that would revolu- tionise medicine: a penicillium mould, left on a discarded Petri dish, produced an unusual substance that appeared to kill many diseasecausing bacteria. When Fleming spotted it, he called it ‘mould juice’ for several months before eventually changing it to the now famous ‘penicillin’. Fleming’s penicillin heralded the era of modern antibiotics and enabled patients with previously untreatable diseases to make full recoveries. Today, while penicillin is used less than before, many of our other antibiotics are also fungal in origin.
Into the deep
Researchers look everywhere to find the next big drug – and that doesn’t just mean on the land! Sometimes they have to don their flippers and dive underneath the water to see what sunken treasures may be there. One such treasure is Tectitethya crypta, a large, pale sponge that you could swim past in the shallow waters off the Caribbean without so much as a second look. This sponge was crucial in the development of AZT, one of the key breakthrough drugs in the treatment of HIV. Even more unusual is the Conus magnus, a poisonous cone snail found mainly in tropical waters near coral reefs. Its venom has led to the discovery of ziconotide, a pain-killer more powerful than morphine that can be used to treat long-term pain. It is probably appropriate, then, that it is also known as the ‘magical cone’.
Finishing where we began
Our journey concludes where you are standing (or at least where you should be standing – see our Nature Guru’s article on the benefits of being outdoors). The soil beneath your feet hides the source of the best-selling pharmaceutical agent in history. The biggest killer worldwide is heart disease and one of the most important weapons in our fight against it is the family of medicine called the ‘statins’. These compounds were discovered in a common fungus, Aspergillus terreus, which lives in soil across the world. Statins have the amazing ability to reduce the amount of cholesterol in your blood, meaning your arteries are less likely to become clogged up – offering protection against heart attacks and strokes. They have become a crucial way of keeping many people healthy. The natural world is magical and it is because of this magic that the great outdoors has become the great pharmaceutical manufacturer. From dragon spit to magical cones, these wonders can be found the world over. When you next go for a walk in the great outdoors, look around (and beneath) you and just think of all the miracle drugs waiting to be unearthed.
penicillium mould covering a mandarin orange.