Comment
Amphibians could help cure our ills, from diabetes to fungal infections – if they don’t go extinct first, says Matthew Gould
I WAS at university in the early 1990s, when toad licking was the latest drug-related panic. I remember many conversations about it, though I don’t remember anyone actually licking a toad, or indeed any other amphibian.
The nearest anyone got to real psychedelic experimentation was an architecture student called Mark, who tried to smoke banana skins. I don’t think it worked. But the toad thing hasn’t gone away. Only last year, the US National Park Service asked its visitors to stop licking toads because of the effect it was having (presumably on both the visitors and the toads).
It turns out the potential of amphibian secretions goes much further. Research presented at a recent Diabetes UK conference showed that a molecule on the surface of East Asian bullfrogs boosted insulin production in mice, which could be an important development for the 400 million people with type 2 diabetes.
This is only the latest discovery of a prospective medicine from frogs, of which there are more than 7500 species, each with its own collection of potentially useful chemicals. No two species have been found to have the same compounds on their skin.
Skin secretions from several Australian tree frogs have already been shown to inhibit HIV infection. Some work against fungal infections and others have different antimicrobial properties. A compound isolated from the phantasmal poison frog has been shown to have 200 times the painkilling potency of morphine.
Frog foam, a substance some species use to make nests, could be useful as a temporary dressing for wounds and burns. Foam from the túngara frog could help provide a slow-release delivery system for antibiotics.
But there is bad news as well. Amphibians are about the most threatened group of animals on the planet, with more than 40 per cent at risk of extinction. Some of the fastest species declines on record have been of frogs.
For more than 20 years, the Zoological Society of London, the international conservation charity I lead, has been at the forefront of amphibian disease research. In the mid-1990s, alongside partners, our scientists discovered that a chytrid fungus was devastating amphibi
