Imagine the very toxins that animals use to hunt, protect themselves, and escape predators transforming into life-saving medicines. It might sound like something out of a science fiction novel, but the idea of using venom to heal goes back to ancient times, with animal venoms reportedly being used in Rome to treat smallpox, leprosy, and fever. Fast forward to the modern day, and we’re using these compounds to tackle hypertension, chronic pain, and heart attacks. By studying these toxic compounds, scientists have turned nature’s deadliest weapons into groundbreaking treatments.

Nature is nothing if not inventive. Venom – a toxic substance produced by animals that is injected into prey or threats through bites, stings, or fangs – has evolved independently more than 125 times across the animal kingdom. This is much more frequent than other major evolutionary feats, like the development of flight. Snake venoms, for example, collectively contain millions of bioactive compounds but, astonishingly, less than 0.01% have been identified and studied for medical use. There’s still vast, unexplored territory ripe for discovery.

The first modern breakthrough came in 1981 when captopril, the first drug derived from animal venom, hit the market. Found in the venom of a South American pit viper (Bothrops jaracara), this tiny compound changed the game for hypertension. It became the first oral ACE inhibitor, a type of medication which helps lower blood pressure by relaxing blood vessels and easing the heart’s workload. Captopril’s success paved the way for future venom-based medicines, proving that deadly toxins could be transformed into safe, effective and widely used treatments.

“Captopril’s success paved the way for future venom-based medicines”

Further developments have happened over time as researchers have delved deeper into nature’s chemical toolbox. Take, for example, the venom of the K’gari funnel-web spider, which contains a molecule that can prevent cells from dying after heart attacks and strokes. This discovery could change the way we treat these life-threatening events, allowing first responders to administer treatment in the field, saving brain and heart tissue from irreparable damage. That’s not all. This same venom is being studied to extend the life of transplant organs, keeping them viable for longer after removal. Researchers are even testing spider venom-derived anti-seizure drugs on lab-grown mini-brains that mimic human brain activity, known as organoids.

It’s not just spiders and snakes: cone snail (Conus magus) venom is the surprising source of ziconotide, a powerful, non-opioid painkiller that targets specific calcium channels in the spinal cord with laser-like precision. The venom of the deathstalker scorpion (Leiurus quinquestriatus) is another star player, offering a potential breakthrough for neurosurgeons through the development of tozuleristide. This fluorescent imaging agent helps distinguish brain tumours from healthy tissue in real-time, transforming the way surgery is performed. Scientists are also looking into venom-based treatments for erectile dysfunction, with toxins from the Brazilian wandering spider (Phoneutria nigriventer) and yellow scorpion (Tityus serrulatus) that trigger erections in those they sting. These venoms might provide an alternative for patients who don’t respond to traditional treatments like Viagra.

“These venoms might provide an alternative for patients who don’t respond to traditional treatments like Viagra”

The discovery of these compounds is often a tale of chance, curiosity, and scientific persistence. For example, the compound that became captopril was discovered after scientists observed the unusual effects and mechanism of that particular snake venom, noting that envenomated creatures experienced a significant drop in blood pressure. This led them to investigate the venom’s biochemical compounds. In many of these cases, the process was a blend of serendipitous discovery, careful study, and a willingness to experiment with nature’s unique, and often deadly, quirks.

But there is a catch: turning these deadly compounds into usable medicines is not an easy feat. Before any venom-derived drug can reach patients, it must go through rigorous testing in laboratories and human trials to ensure it’s both safe and effective. This means meeting strict standards set by regulatory agencies, a process that can take years and cost millions of pounds. Securing enough venom to produce these drugs at scale is another obstacle. Venoms are tough to extract from animals consistently, and synthetic production is not easy. Creating bioactive compounds in the lab requires sophisticated techniques to replicate the exact structure and function of venom molecules, and many of the proteins in venoms are difficult to produce artificially while maintaining their medical benefits.

Conventionally feared as deadly toxins, venoms and poisons continue to emerge as powerful tools in modern medicine. The full potential of venom-based therapies is still largely untapped, with many applications yet to be discovered. As biotechnology continues to evolve, the future is bright – nature’s deadliest substances could be transformed into some of the most powerful and precise medicines of the future.

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