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| Saving What Remains |
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MEDICINAL DRUGS (continued) The rainforest may someday provide the cure for AIDS, pancreatic cancer, antibiotic-resistant staph infections, lassa fever, or Alzheimer's disease, if given the chance to do so. Unfortunately, as primary forest cover is diminished by 1-2 percent every year, it is projected that 20-25 percent of the world's plant species will be extinct by the year 2015. Perhaps in some remote Andean valley, slated for destruction today, lives a rare orchid which has developed an anti-viral chemical that kills HIV, halts cancer, or slows aging. In addition, the shamans who provide much of the insight into identifying these plants and their uses, are disappearing at an even faster rate as their villages seek a more Western lifestyle. These shamans are generally elders and when they die, their unique knowledge of traditional uses of rainforest plants will die with them. Some organizations are trying to prevent the loss of medicinal knowledge when indigenous elders die. The Terra Nova Rainforest Reserve is the first ethnomedicinal forest reserve designed to ensure that medicinal plants will be available for local use. The reserve encourages the use of such plants and has also implemented a program teaching youths about uses of medicinal plants so this knowledge will not die, but be passed on to future generations and researchers. National botanical gardens, like those of Missouri and New York, are playing an important role in propagating medicinal plants that are either threatened in the wild or so rare that collection cannot satisfy demand. Several gardens have propagated such medicinal plants and freely distributed seedlings to peasants who can integrate them into their traditional food crops. The plants can provide substantially more cash than many traditional crops like bananas, coffee, and cocoa. Animals as an inspiration for drugs Animals also provide compounds useful to humans as medicinal drugs. Both leeches and vampire bats have powerful anticoagulants they use in feeding on their prey. From the saliva of the leech comes hirudin, which is now used to dissolve blood clots in humans. The vampire bat has a salival substance that can be used to prevent heart attacks. The slimy secretions of frogs are used to treat infections, mental disorders, and even HIV, while scientists hope that one day blood from the ubiquitous (in the western U.S.) western fence lizard (more popularly known as the "blue-belly") will help prevent or cure Lyme disease. ABT-594 is an experimental painkiller derived from the skin secretions of Epipedobates tricolor, a colorful poison arrow frog, and crocodile blood is being examined for its anti-HIV properties. PESTICIDES Plants have been synthesizing chemicals for millions of years to protect them from predation by insects and infection from disease. Thus rainforest plants have developed a complete array of natural pesticides. These pesticides can be isolated, and some can be synthesized in the laboratory by pharmaceutical companies. These natural pesticides are effective for protecting cultivated crops from destruction by pests and disease, without the adverse effects of chemical pesticides like DDT. New research shows that using natural predators like wasps and flies combined with limited use of pesticides is more effective in eradicating pests in the tropics than regular spraying with synthetic pesticides. Chinese scientists have even engineered wasps to deliver lethal viruses to insect pests. In addition to protecting crops from infestation, many rainforest plants can be used as insect repellents. The roots of the liana, a philodendron from American rainforests, have an odor that keeps away mosquitoes, while the bright orange berries of another New World plant, Bixa orellana, are effective in deterring biting insects, in addition to being used as a body paint and dye. These compounds may be further studied and analyzed by pharmaceutical companies to create new insect repellents that might be less detrimental to the skin and plastic materials than conventionally-used DEET. These highly effective insect repellents are more ecologically sound and inexpensive to produce. Review questions:
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