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Earthly Goods: Medicine Hunting in the Rainforest.
The rain forest as nature's pharmacy has become the mantra of schoolchildren and a favorite fund-raising slogan for a host of conservation groups. Based on the promise of these forests, new pharmaceutical companies have been capitalized, and government and corporate funds made available in a manner unimaginable to field biologists just a few years ago. Although it is still too soon to assess the effectiveness of this global hunt for new drugs, Earthly Goods is an invaluable chronicle of the quest, and essential reading for those anxious to understand the current status of medicinal plant exploration in the tropics. Picking up where Margaret Kreig left off 30 years ago in Green Medicine, Joyce reviews the contributions that plants have made to our pharmacopoeia. He also introduces the players in the drama of drug discovery, tracing a lineage of scientific inquiry from Dioscorides to Alexander von Humboldt and beyond to the incomparable Richard Spruce. At the end of this legacy is Richard Evans Schultes, former director of the Botanical Museum at Harvard, whom Joyce quite properly credits as the father of modern ethnobotany. If Schultes heads up the community of ethnobotanists, Harvard's E.O. Wilson is the dean of a different group of biological explorers, those who seek to identify pharmacologically active compounds not by consulting indigenous peoples, but by following the clues of nature. These researchers seek plants which are taxonomically affiliated with species that have yielded drugs in the past. They collect organisms such as fungi and insects known to be of chemical interest. They spend a lot of time simply gathering soils from around the world and assaying the microorganisms found within. Such an approach allowed Merck & Company to discover Mevacor (generic name, Lovastatin), a drug which lowers cholesterol. Derived from a soil fungus, it earned Merck $735 million in sales in 1990. The major practical proponent of this school of exploration is Dan Janzen, the visionary and irascible ecologist who orchestrated the pioneering deal between Costa Rica's National Institute of Biodiversity (INBio) and Merck. At a time when the pharmaceutical giant was spending more than $1 billion a year on research, INBio received $1 million in advance to collect a thousand or more species of plants, insects, and soil samples. Was the controversial deal worth it? As an executive of a rival company tells Joyce, Merck "wrung a good $10 million worth of good press out of a mere $1 million gamble." If there is a flaw in this fine book, it is the author's occasional failure to follow up on information that challenges the book's central premise. Joyce, for example, heralds the work of Richard Spruce without noting the most curious anomaly of his explorations. In six years on the Rio Negro in the heart of the Amazon, Spruce, a keen ethnographic observer, saw almost no evidence of Indians using medicinal plants. We also learn that Schultes has collected over 2,000 medicinal plants, but we are not told that not one has yielded a new drug or even a compound that has entered clinical trials. Bob Raffauf, a natural products chemist and co-author with Schultes of The Healing Forest, is passed over in a page. Yet it was Raffauf who, working for Smith, Kline & French between 1950 and 1965, assayed tens of thousands of plants from around the world, including hundreds of Schultes' collections. In 15 years of research only 10 useful compounds were found. Not one became a drug. His was a sobering experience which left him convinced that rain forests ought to be saved for their inherent value. It would have been useful to hear more from him. It would also have been interesting to have had more critical discussion about SP-303, the compound upon which the fortunes of Shaman Pharmaceuticals may rise or fall. SP-303's source is an extremely common medicinal plant of the Northwest Amazon known as the blood of the dragon. Used by dozens of indigenous societies, it has topped the list of plants worthy of pharmacological investigation for years. While it is laudable that Shaman is finally doing the work, one may question the extent to which this species proves the legitimacy of the ethnobotanical approach to drug discovery. Like quinine, blood of the dragon stared investigators in the face. Joyce notes that Shaman, after only two years, already has three compounds extracted from this plant in development as drugs. But the jury is still out on all of them. Elsewhere Joyce is more cautious and critical. To those in the conservation movement who make irresponsible claims of imminent cures for AIDS and cancer, and who predict great streams of money flowing into indigenous communities, he warns of a backlash of disappointment. According to most natural products experts, the chances of finding a compound for a specific disease are at best one in 10,000. If one is found, the chances that it will prove safe and effective are one in 10. Then there is the obvious issue of securing market share. To transform a drug into a commercial product takes on the average 10 years and $350 million. Once the development costs are discounted, and assuming that the product nets annually $10 million, a royalty rate of 3% would yield approximately $30,000 a year. Clearly, Joyce concludes, indigenous societies are not going to be getting rich, even assuming one can figure out where to direct their royalties from new drugs. Still the search is worth it. As Michael Balick, Director of the Institute of Economic Botany at the New York Botanical Garden, notes, "Finding one drug from the rainforest that will save lives would be worth more than all the lectures by famous people and all the rock concerts. If you can just hold up one plant. My mission in life is to find such a plant. "This, indeed, is the central theme of Earthly Goods. It is not a book about indigenous peoples. Indeed for a book that celebrates ethnobotany the native voice is surprisingly mute. We learn almost nothing about what the native peoples think and feel about their plants. Rather it is a timely account of the efforts of Western scientists to tap the natural world for plant drugs that will hopefully benefit all humankind. Article copyright American Botanical Council. ~~~~~~~~ By Wade Davis">by Christopher Joyce. 1994. Little Brown/Time Warner Books, NY. 228pp. $22.95. ISBN #C:InetpubwwwrootData16-4744-08-8. Available from ABC Books, Item # B088.p#