Continued from Part II
For centuries, humans have turned to the plant kingdom for new medicines. Aspirin was derived from the bark of the willow tree. Digitalis, a heart medication, came from the foxglove plant. Codeine and morphine came from the poppy. And the cancer-fighting drugs vinblastine and vincristine are derivatives of the periwinkle plant.
But we’re only now understanding the medical value that surrounds us in the animal world. Unfortunately, because of habitat loss due to farming, logging and urban sprawl, many species of animal die off each year before we can study them.
This is especially true for poison-frogs – which live in some of the most sought-after land in South America. Aside from the appalling loss the planet suffers, each extinction is also a potential loss for humans of a cure for cancer, Alzheimer’s disease, ALS or AIDS.
And unlike plants, there’s no guarantee that simply breeding frogs in captivity will preserve an animal’s unique chemical make-up.
Edson Albuquerque is another expert on poison-frogs and has worked closely over the past 20 years with John Daly. He agrees that trying to protect the natural setting of these animals is a major challenge.
“If you pick up the animal and put it in captivity, particularly a frog that has to synthesize its toxin from the food that they take, and you don’t know what its diet is you might lose that toxin,” Albuquerque says.
That’s precisely what he and Daly found: poison-frogs bred in captivity stop being toxic. They believe the frogs develop their toxic skins by eating ants, millipedes, beetles and other bugs that are, themselves, very slightly toxic. After a lifetime of eating, the frogs have quite a store of poison in their skin.
They believe captive-bred frogs can be made toxic again by simulating their natural diet using flies dusted with carefully selected chemicals. Unfortunately, they know only a half-dozen of the 500 or so chemical compounds the frogs probably need to become so toxic.
All of this highlights the importance of saving as much of the rain forest habitat of the poison-frog as possible before it’s too late.
“What I’m really trying to communicate is this enormous ignorance that still exists and it’s not just dotting the i’s and crossing the t’s,” Zasloff says. “We basically don’t know virtually anything about what keeps these creatures alive. We know almost nothing.”
Previous stories in this series:
- PART I: Introducing a bitter little frog
- PART II: Harvesting a medical bounty
- PART III: Loss of habitat threatens poison-frogs – and your future health.