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Africa's Malaria-Fighting Trees Threatened


An herbalist selling medicinal plants in Shinyanga, Tanzania.

An herbalist selling medicinal plants in Shinyanga, Tanzania.

Researchers warn that East African plants that could cure malaria could disappear before scientists have a chance to study them.

The World Health Organization estimates 800,000 people die of malaria each year, most of them young children in Africa.

A new book by scientists at the World Agroforestry Centre, "Common Antimalarial Trees and Shrubs of East Africa," identifies 22 tree and shrub species that traditional healers in East Africa use to fight the disease.

But, the researchers say, they are being cut down for cooking fuel and other uses and could disappear before scientists have a chance to study them.

Herbal medicine

A person suffering from malaria in East Africa is likely to visit a local herbalist for treatment. Lead author Najma Dharani at the World Agroforestry Center in Kenya says the traditional healer may recommend the patient take a few grams of a plant known locally as knobwood.

Either root or bark may be used, fresh or as powder. "It's quite bitter," she says. "Drink it for three or four days, until it cures a person."

Dharani and her colleagues at the Kenya Medical Research Institute have used modern science to identify promising malaria-fighting compounds in knobwood and 21 other trees and shrubs native to the region. The threatened African wild olive, Olea africana, has anti-malarial properties that scientists say deserve further study.

The threatened African wild olive, Olea africana, has anti-malarial properties that scientists say deserve further study.

Traditional cures at risk

She has spent the last 12 years studying medicinal plants in East Africa with the potential to treat a range of diseases. A lot more research is needed to identify how effective they are and how they work, but she notes that they have been used by traditional healers for centuries.

"This is not today's knowledge," she says. "This is very old knowledge, indigenous knowledge, which has been disappearing because the youngsters don't take it (up)."

The knowledge is not all that's disappearing. Dharani says the some of these anti-malarial trees and shrubs are being cut down at an alarming pace, along with other wood in the area, largely to make charcoal. That's the cooking fuel of choice for many poor people around the world who can't afford other options.

Limited options for treatment

She understands the economic motivation to cut down the trees. But, she says, it will be these same poor people who will ultimately suffer.

"They don't have access to clinics. They don't have doctors," she says. "They have to go hundreds of kilometers to reach clinics. So, it's so very important for local communities to conserve these trees. If [the trees] completely vanish, they will remain with nothing."

The World Agroforestry Center is working to reduce deforestation by encouraging people to grow their own trees for timber or firewood, rather than harvesting the forest. The center also is helping communities plant medicinal trees and shrubs, and conserving samples of the trees in its genebanks and nurseries.

Knobwood extract would not be the first plant to cure malaria. The first anti-malarial drug, quinine, came from the bark of a South American tree. The latest treatment, artemisinin, comes from a Chinese shrub. The next cure could come from East Africa -- but not if the last tree is burned up as charcoal.

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    Steve Baragona

    Steve Baragona is an award-winning multimedia journalist covering science, environment and health.

    He spent eight years in molecular biology and infectious disease research before deciding that writing about science was more fun than doing it. He graduated from the University of North Carolina at Chapel Hill with a master’s degree in journalism in 2002.

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