From poison to potion: Toxins turned into life-saving drugs

Story highlights

  • Some toxins could be turned into life-saving drugs
  • Cobra venom could hold the key to relieving chronic pain and pain during surgery
  • Certain proteins in the perspiration from a fire-bellied toad may heal wounds
Nature, it turns out, is one big medicine cabinet. We can thank the willow plant for the salicin that turned into aspirin, and the poppy for the pain-killing powers of morphine.
Even poison can become potions — a viper's venom, for instance, is part of a powerful anti-clotting drug that can keep blood flowing instead of clumping up.
Increasingly, such toxins are proving to be attractive sources of potentially life-saving drugs.
About half of existing medications emerge from the flora and fauna that surround us, which hints that potentially thousands of additional drugs are yet to be discovered, albeit protected by the vicious bite of a poisonous snake or the harmful blood-sucking of a tick.
From cancer treatment to painkillers, here are the agents that may be hazardous materials today but could evolve into powerful medications tomorrow.
Pufferfish: Canceling chemo pain
Experienced chefs know how to slice into the pufferfish to avoid the deadly tetrodotoxin, which disrupts the nervous system and can cause fatal paralysis of important muscles that control breathing and heart rate.
But the toxin of the spiky fish may also treat chronic pain, such as that related to chemotherapy. Researchers at the John Theurer Cancer Center have found that the toxin is 3,000 times more potent than the pain-killer morphine, without the crippling side-effects of addiction and nausea.
So they are testing the tetrodotoxin-based pain reliever in a small group of cancer patients to ensure its safety and effectiveness. They will have to compare its efficacy against that of existing drugs used to treat chemotherapy pain before the U.S. Food and Drug Administration will consider it for approval.
Shark: Making bacteria feel unwelcome
The skin of a shark might appear as smooth as rubber, but up close it's so rough that some cultures used the skin like sandpaper. Sharklet Technologies, however, is pioneering a new use for the fearsome fish's skin, which is constructed of sharp, interlaced ridges that together make an inhospitable environment for microbes.
The company is developing medical devices such as urinary catheters that mimic the texture of shark skin to ward off common infections from staphylococcus aureus, methicillin-resistant staphylococcus aureus (MRSA) and pseudomonas aeruginosa.
The catheters could help to reduce the tide of urinary tract infections that plague around a quarter of all patients who use the devices for a week or more.
King cobra: Taking the bite out of morphine
One bite of a King Cobra could kill a human, but that fatal venom could also hold the key to relieving chronic pain and pain during surgery.
Professor Manjunatha Kini of the National University of Singapore, who is developing the compound, says that it could be 20 to 200 times more potent than morphine. Like the pufferfish toxin, though, King Cobra poison lacks the addictive properties of that painkiller and others like it currently on the market.
Within a year, Kini hopes to test the drug in patients. In recent animal tests, mice receiving the agent were able to withstand almost twice the thermal pain of animals that did not take the compound.
Tick: Clearing up clots
Once a tick buries itself in flesh, it spits. And special properties in its saliva ensure that its food supply — blood — flows easily without any obstructions.
That could also come in handy for patients whose vessels are in danger of closing up from clots. So professor Manjunatha Kini at National University of Singapore isolated molecules in tick saliva to develop a potential drug that is 70 times more potent than the natural blood-thinning agent found in a human body.
The drug has performed well in animal testing so far, but still has more than a year of additional research before it will be ready to test in people.
Sea anemone: Retraining immune cells
Seattle-based biotechnology company Kineta is developing a treatment based on sea anemone toxin for patients with auto-immune diseases like multiple sclerosis, in which the body's immune cells mistakenly attack its own healthy cells.
The toxin, which the anemones release to discourage predators like lobsters, contains a compound called ShK-186 that affects certain potassium channels in the body. Antibodies that bind to these channels may be responsible for some autoimmune conditions, and targeting just this defect may provide a more effective treatment.
Current therapies often disable more of the immune system, which makes patients vulnerable to other immune-related problems, says Dr. Chuck Magness, Kineta's CEO and president. The drug also appears to regulate metabolism, which means it could possibly play a role in treating obesity.
Currently, the sea anemone toxin-inspired drug is in the first phase of human clinical trials.
Fire-bellied toad: Healing wounds
This poisonous little toad secretes a venom-laced sweat when provoked, but certain proteins in that toxic perspiration may help to heal wounds.
The peptides promote blood vessel growth, says professor Christopher Shaw of the Queen's University at Belfast School of Pharmacy who is studying the toad. A drug using this toxin could minimize the growth of scar tissue by speeding up the healing process.
The potential drug is less than a year away from entering human trials and has already been patented in China and the United States.
Waxy monkey frog: Keeping blood vessels in check
This frog's light-hearted name masks the seriousness of the toxin embedded in its skin.
Last year, a ring of horse owners was busted for doping their racehorses with the toxin that simultaneously made the animals numb and hyperactive.
Used more judiciously, however, the frog's venom could control blood vessel growth, known as angiogenesis, which may be useful in starving cancer cells.
Some cases of diabetes-related blindness are also caused by out-of-control blood vessel growth, which damages the retina, and rheumatoid arthritis is linked to an explosion of vessels that feed inflamed areas with more disease-causing compounds.
Christopher Shaw of the Queen's University at Belfast School of Pharmacy says that the frog's anti-angiogenic properties could prove useful in treating these diseases, although researchers have to work fast.
Mass extinctions of various frog species threaten to wipe out species such as this one before venoms can be isolated and analyzed.
The waxy monkey frog-based agent should be set for human trials within the year.
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