https://www.bbc.com/future/article/20200507-medicines-and-drugs-from-animals-venom
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These days, many of us are more likely to think of wild animals with a source of human illness rather than cure.
But like plants, which have been part of our medicine cabinets ever since the Neanderthals used poplar tree bark as a painkiller, animals have long been exploited for their medicinal properties.
For example, Traditional Chinese Medicine (TCM) uses ingredients from 36 animal species including rhinos, black bears, tigers and seahorses – many of which are endangered. Ayurvedic medicine recommends snake venom to treat arthritis, while tarantula bites and ground-up fangs traditionally been used in South America, Asia and Africa to cure a variety of ailments, from cancerous tumours to toothaches and asthma.
Ayurvedic medicine, which is thousands of years old, is just one form of medicine that recommends animal-derived treatments
(Credit: Getty Images)
The vast majority of these traditional remedies are not backed up by any scientific evidence – and the pursuit of animal parts has already contributed to several extinctions, including the western black rhino and northern white rhino. Up until recently pangolins, of which some species are critically endangered, were often raised at wildlife farms in China for their scales in TCM, and are thought to have been the source of Covid-19. In fact, top scientists warned this week that our exploitation of wildlife is likely to lead to more frequent and deadly pandemics in the future.
But there might be a way to use wildlife responsibly, and that’s by studying their chemical ingredients at a molecular level. Thanks to modern technologies, no animal ingredients are required at any stage – just a DNA sequence.
Unlike plants, from which people have been isolating specific compounds and turning them into medication for more than 100 years, in animals, specific molecules with medical potential have historically been too difficult to locate or extract. But that’s changing – meaning that while more future diseases are likely to come from animals, some of the most exciting drugs of the future will come from them, too.
“We have looked at plants for a long time, but we have only just scratched the surface with animals,” says Christine Beeton, an immunologist with the Baylor College of Medicine. She studies how peptides derived from venoms can be used to treat autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and myotonic dystrophy.
Thanks to evolution, we can find large molecules called peptides, which are siblings of molecules that exist in the human body, in other animals. This means that peptides from animals ranging from snails and spiders, to salamanders and snakes, can hone in on our own cellular components like a divining rod, with very precise effects.
An expert extracts venom from a rattlesnake in Sao Paulo, Brazil (Credit: Getty Images)
Peptides are composed of the same building blocks as proteins, but in much smaller chains – one can think of them as “mini proteins”. Because they are 10 to 40 times larger, however, than small molecule drugs such as aspirin, peptides are much more specific in what they target. As a result, they are far less likely to have side effects.
Today, the modern tools of genomics, proteomics and transcriptomics – the branches of biology that catalogue the chemical structure of DNA, proteins, and their messenger molecules – have revolutionised how scientists can discover compounds in animals that have the potential to become drugs.
Now we can screen hundreds of compounds in a month. Fifteen years ago that wouldn’t have been possible – Christine Beeton
“Now we can screen hundreds of compounds in a month. Fifteen years ago that wouldn’t have been possible. You would have had to look at them one by one, and it would have taken 10 years,” Beeton says.
Instead of having to laboriously milk snakes and scorpions for their venoms in order to analyse them, researchers can simply mine databases of codes to find peptides with specific properties.
Numerous drugs are already available on pharmaceutical shelves: Enexatide, derived from the saliva of the Gila monster, prescribed for type two diabetes; Ziconitide, extracted from cone snail venom, for chronic pain; Eptifibatide, a synthetic modelled on the venom of the southern pygmy rattlesnake, administered to prevent heart attacks; Batroxobin, extracted from South American pit vipers and used in several different blood treatments, including the appropriately named “Reptilase”; and Captopril, the first pharmaceutical derived from an animal, an anti-hypertensive approved by the US’s Food and Drug Administration (FDA) in 1981.
Article continues at: https://www.bbc.com/future/article/20200507-medicines-and-drugs-from-animals-venom
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