Because poisons have proved to be a grateful source of inspiration for pharmaceuticals.

clubfoot frogs (Atelopus) are very colorful and diverse: no fewer than 113 different species live in Central and South America. For most species, however, their populations are declining and a quarter of the species are even suspected to be already extinct. And with that we may have already lost a lot more than we will ever realize, researchers now argue in the magazine Toxicone: X.

poison

Because clubfoot frogs are not only colorful, but sometimes also poisonous. For many species, however, we do not (yet) know whether they are poisonous, which toxins they produce and how those toxins are put together. And if species die out, we’ll never know either. And that is a problem, according to researchers.

Medicines

For the poison of animals has repeatedly proved to be a rewarding source of medicines. For example, an ingredient from snake venom is already being used in blood pressure-lowering medication and painkillers are made using an ingredient derived from the venom of cone snails. And several studies are underway into clinical applications of venom components produced by scorpions, centipedes and puffer fish.

It therefore certainly does not seem inconceivable that the poison of clubfoot frogs offers similar possibilities. But then we have to analyze it – before the toads disappear for good. “There are nine species of clubfoot frogs in Central America,” said Rebecca Tarvin, one of the authors of the review in Toxicone: X. “And seven of them have been researched into the diversity and quantity of toxins. But most Atelopusspecies live in South America, where the fewest studies have been done. There are entire countries – like Bolivia and Guyana, where no species have been assessed (…) We don’t know whether they are poisonous or not. One of the conclusions of our paper is that with the loss of these animals we probably also lose some chemical diversity. They have toxins that cannot be found anywhere else on Earth.”

Threats

And it seems almost certain that some of the barely studied toads will lose out. In 2005, research showed that of the 53 Atelopusspecies for which sufficient data was available, had to do with population decline 81 percent. And 56 percent may have already become extinct. There are several reasons why the toads are having a hard time. For example, destruction of their habitat seems to play a role. However, the main cause is a fungal disease, which makes many victims among the toads. “Many species have been completely wiped out,” Tarvin said.

And so time is running out. Because there is still a lot we don’t know, according to the research by Tarvin and colleagues. In their article, for example, they show that the venom of only 16 of the 113 known clubfoot frog species has been analyzed to date. Some of those toads studied make the toxins on their skin themselves. In others, they appear to be the work of bacteria that live on the toads’ skin. Given their bright colors – which in nature often serve to warn predators – there are also many poisonous species to be found among the clubfoot frogs that have not yet been further investigated. But, Tarvin points out, it’s certainly not proven that all clubfoot frogs are poisonous. Also, the toxins on the skin do not always have the same function; in some species they may be intended to keep predators at bay, but in others the substances on the skin can again protect against disease (perhaps even the dreaded fungal disease). Follow-up research should provide more clarity about all this and show which species are poisonous, how that poison is produced and what function it has. Tarvin and colleagues immediately put their money where their mouth is, because they intend to focus on researching the often brightly colored toads in the near future. “The main reason for me to study them is that they have almost disappeared,” said María José Navvarrete-Méndez, not involved in the study but part of Tarvin’s research group and one of the scientists specifically investigating the venom of these toads. . “If there’s anything we can do to make sure they recover or we learn something from them before they go extinct, we should do it. It is our responsibility.”