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Saving the Rain Forest By Using It to Find Drugs

19 November 2012
Published in Life
Written by  Kirstin Roundy
Saving the Rain Forest By Using It to Find Drugs Tom Kursar

Few people can say that their work has helped to save an island. But Phyllis Coley and Tom Kursar are not ordinary scientists.

The island is Coiba, a chunk of land off the coast of Panama. Since the early 1900s, Coiba had been the site of a Panamanian prison. The relative lack of activity on the island meant that 80 percent of its natural habitat was still intact. This included trees and animals that had disappeared from the mainland, such as the Crested Eagle and Scarlet Macaw, as well as several animal subspecies.

However, in 2004, the remaining prisoners were moved from the island, leaving the Panamanian government to decide what to do with Coiba. One option was to turn it into a tourist destination, complete with golf courses and hotels.

Bioprospecting in Panama

Enter Coley and Kursar, researchers from the University of Utah who study the interaction between plants and the herbivores that feed upon them. As a married couple, they spent their life together doing research in the world's tropical rain forests. However, many of their research sites had fallen prey to logging and commercial development.

"We find our survey of ecology of plant defenses absolutely a fascinating puzzle but rain forests are disappearing. What can we do about it?" Coley remembers thinking at the time. "If we could find something that was valuable in rain forests then there would be an incentive for those countries to save the rain forests."

Coley and Kursar came up with a solution, modeled after a program in Costa Rica: bioprospecting. Instead of searching for gold, bioprospectors 'mine' plants, bacteria, and fungi for novel, often toxic, biological compounds that combat illnesses such as cancer and infectious diseases.

Mature leaves are one of the most common biological samples collected by bioprospectors. However, through their studies the Utah scientists found that it is young leaves that are particularly tasty to herbivores because they are tender, nutritious, and full of nitrogen. "We're really interested in why the world is green, why the insects or herbivores haven't eaten up all the plants," says Coley.

To defend themselves against herbivores, new leaves produce poisons; in fact, 50 percent of their dry weight is made up of toxic compounds, much greater than mature leaves. For this reason the scientists thought it would be more efficient and productive to focus bioprospecting efforts on young leaves.

In 1995, Coley and Kursar started a program to look for potential drugs in the jungles of Panama. Since then, program scientists have isolated a total of 216 biologically active compounds, some from young leaves. One of the most promising is Coibamide A, which was found to inhibit growth of cancer cells. Isolated from cyanobacteria (blue-green algae) off the coast of Coiba, the compound was patented in 2011. Other compounds have the ability to destroy bacteria and kill parasites responsible for leishmaniasis, malaria and Chagas disease.

There is still a long way to go before any of the compounds can be turned into marketable drugs. Only one out of 50 drugs make it to clinical trials, with associated costs estimated at $880 million per drug.

More than Drug Discovery

Central to Coley and Kursar's plan was that as much of the work as possible be done in Panama by Panamanian scientists and students. "We said, right at the very beginning, that [sending samples back to the US] was ridiculous," says Kursar. "They [Panamanians] need to get immediate benefits." According to Coley and Kursar, these efforts have helped Panamanians to become researchers themselves and realize the value of their rainforests, the program's biggest success.

The program was eventually funded by the International Cooperative Biodiversity Groups (ICBG), a coalition of U.S. government agencies that use drug discovery programs as incentives for conservation, and has brought in $8.5 million in grant money for research efforts in Panama. Currently, the program is administered by the Smithsonian Tropical Research Institute and includes U.S. scientists, Panamanian scientists, and private companies.

What started seventeen years ago as a small program in Panama has now garnered the attention of the world. In 2005, Coiba and its surrounding islands were designated a World Heritage Site, an internationally recognized protected status. Earlier this year, the group received one million dollars from the Global Environmental Facility (GEF) to continue the drug discovery program in Panama and serve as an example for other countries.

"We wanted it [the Panama project] to be an example. [But] we want it to be much, much bigger than Panama," says Kursar. "We're not interested in being politicians. And that's why it was really good to get this GEF attention because...we're hoping it will grow and develop."

Referring to the success of the program, Coley says, "My mother always said, 'Well, what earthly good is that? Who cares about caterpillars eating baby leaves?' If we hadn't spent 25 years doing the basic science with no obvious application, it [the bioprospecting program] never would have occurred to us...This whole project was a labor of love."

Coley and Kursar have since turned over the reins of leadership for the project to Panamanians. Currently they are working in other S. American tropical rain forests, continuing their work researching the interaction between herbivores and plants.

 

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