AIDS Medicine May Save Cameroon Rain Forest
Air Date: Week of November 3, 1995
An extract found in the African nation of Cameroon may help AIDS patients and the rainforest itself. David Baron of member station WBUR reports on the recent discovery of a potentially helpful drug in this heavily harvested rainforest, and how the National Cancer Institute is preparing for its possible demand.
CURWOOD: Natural medicines from plants hidden in the world's tropical forests could be worth billions to humanity, scientists say, if those medicines can be discovered before the forests are destroyed. Some environmental activists suggest that such discoveries could help save rainforests. Many companies engaged in drug prospecting have promised to pay royalties to the nations where drugs are discovered to encourage conservation. Thus some say markets can be used to protect the rainforests. But others say that should a miracle drug be found, it might well set off a stampede that would wreck the ecosystem. David Baron of member station WBUR traveled to the African national of Cameroon to check on the habitat of a plant that holds strong promise in the fight against AIDS.
(Bird calls, walks through the jungle)
BARON: Johnson Jato has come to a hillside on the outskirts of Cameroon's capital Yaounde, as the sun sinks beyond the small homes and plantain trees in this lush tropical landscape. Jato, a professor of pharmacy at the University of Yaounde, stoops in the middle of a clearing in the weeds to check on his plants.
JATO: This is one of them. They started small, but now they are growing.
BARON: The plants look like tiny trees with slender, pointed, shiny leaves. Full grown, the plants will become vines, growing high into the rainforest canopy. Jato and others believe this plant species, with the unwieldy name ancistrocladus korupensis, could help solve 2 worldwide crises: the destruction of the world's rainforests and the AIDS epidemic. The plants contain a compound called michellemine-B, which in the test tube at least stops the AIDS virus cold.
JATO: It's in the leaves. We have tried to test every other part beginning from the main trunk to the small branches, but we haven't seen michelemine-B in any other part of the plant.
BARON: No one knows if michellemine-B will turn out to be a useful AIDS drug. Studies show while it can keep HIV from reproducing, it may also be toxic. US researchers hope to try the compound in AIDS patients for the first time this year. There's a lot of excitement surrounding michellemine-B. It's the most promising find so far in a decade-long program run by the United States government.
CRAGG: The goal is to explore nature as a potential resource for drug discovery.
BARON: Gordon Cragg heads the Natural Products branch of the US National Cancer Institute. Since 1986, Cragg's program has screened some 70,000 chemical extracts of plants, animals, and microbes from tropical rainforests and coral reefs. The main purpose has been to find new cancer and AIDS drugs. But Cragg says there's a secondary goal.
CRAGG: We are very interested in trying to promote conservation. And the hope is that if we get a good drug this will be an incentive. That countries will realize that natural resources do have potential in this area.
BARON: Many valuable drugs have come from the rainforests including quinine for malaria, and the powerful anti-cancer drugs vinblastine and vincristine. Pharmaceutical companies have gotten rich off such drugs. The countries where the drugs were found have gotten nothing. Cragg wants to see that change. The National Cancer Institute has promised as part of its decade-old program that if it finds any drugs the country of origin will receive royalties. Some pharmaceutical companies have followed the NCI's example, and are conducting their own searches for rainforest drugs. Again, with the promise of royalties. But Gordon Cragg says drug development takes many years and no marketable medicines have yet been developed from any of these new efforts. Michellemine-B could be the first.
CRAGG: In many ways, michellemine-B could be the interesting trial case here of just how is this going to work.
(Motors, honking horn)
BARON: In the Cameroonian port of Douala, giant logs from ancient trees lie stacked row upon row ready to be shipped overseas and made into furniture, plywood, and window frames. Cameroon is losing its forests at one of the highest rates in Africa. When the National Cancer Institute discovered that the ancistrocladus vine, an unknown species a decade ago, produces michellemine-B, a potential AIDS drug, environmentalists were thrilled. It was a chance to demonstrate in concrete terms the value of leaving Cameroon's forests standing. But Steve Gartlan, a representative in Cameroon for the Worldwide Fund for Nature, soon realized there was a problem. The discovery could actually fuel destruction of the forests.
GARTLAN: If it got out in the Western press that ancistroclatis was a cure for AIDS, there would be charter flights arriving in Yaounde. There would be uncontrolled searching, ripping off of the forest to find these plants. You would run the risk of getting the whole forest completely destroyed in the uncontrolled search for these plants.
BARON: So, Gartlan's organization is working with the National Cancer Institute to prepare for the possible overwhelming demand for ancistrocladus leaves if michellemine-B proves effective. The plan now is to domesticate the plant, to turn it into a cash crop that farmers can grow, so people don't have to scour the rainforest for wild vine.
(Running motor, birdsong)
BARON: At a small nursery in the rainforest in central Cameroon, forestry worker Christopher Njoya is raising large numbers of tiny ancistrocladus vines. Njoya has learned to grow the plants from stem cutting, and he's had good success in getting the cuttings to root.
NJOYA: We have rooting rates up to about 70% in 3, 4 weeks.
BARON: Njoya is trying to breed plants with especially high levels of michellemine-B, and thus especially high value. And he's learning how to grow the plants outside their native habitat so they can be grown on farms outside the rainforest. Some test farms have begun cultivating the vine. If michellemine-B proves to be a viable treatment or cure for AIDS, the drug could have a market in the hundreds of millions of dollars. Joseph Edou, economic advisor to Cameroon's prime minister, says this vine could provide his poor country with 2 new sources of income.
EDOU: One for farmers and one for the government. The farmer can benefit it as a personal revenue, and the government can get royalties in the public treasury.
BARON: But here again, some environmentalists question if the National Cancer Institute program will achieve its desired goal of promoting conservation. After all, if Cameroonians can grow the ancistrocladus vine outside the rainforest, what incentive will they have to protect the forest? Furthermore, Cameroon's government has made no promises that any royalties it receives will be used on conservation programs. Gordon Cragg of the US National Cancer Institute says he hopes and expects some of the money would go in that direction, but he can't mandate how another government spends its funds.
CRAGG: This is perceived as a weakness in this whole compensation issue. That are you sure that it's going to get back to the right people? But the, you know, the rationale for promoting conservation is, well, gosh, we've found a plant that's produced a potential anti-AIDS drug, a plant which was literally unknown in that region. What else is there out there in your forest? Hopefully this will provide that incentive to many countries around the world to conserve and look at their resources.
BARON: Environmentalists who agree with this concept still have one nagging fear. What if, as could well happen, michellemine-B proves to be ineffective or too toxic when tried in AIDS patients? What if no drugs are found in Cameroon's rainforests? Could the National Cancer Institute's program backfire? After all, the program encourages forest preservation for economic reasons. If a country has no medicines waiting to be harvested in its forests, it might conclude by that same economic logic that the rational course of action is to continue turning its trees into lumber. For Living on Earth, this is David Baron reporting.
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