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Nature’s Rx

(Excerpts from the April 2000 NATIONAL GEOGRAPHIC)

By Joel L. Swerdlow

From the forests of Madagascar to the clay pits of Georgia, people all over the world rely on nature to treat what ails them.

Party sounds float up from a swimming pool in Washington, D.C. Twenty children shout and splash, toss balls, and snack on sandwiches, cookies, chips, and sodas. The guest of honor is nine-year-old Audra Shapiro, who has just finished two years of chemotherapy and whose leukemia is in complete remission. Her recovery from this cancer depended on a plant that originated halfway around the world.

Until the early 1960s Audra’s disease would have meant sure death. Now the long-term survival rate for childhood leukemia is above 90 percent, thanks in part to vincristine, a chemotherapeutic drug made from the Madagascar rosy periwinkle. Vinblastine, another drug made from the same plant, helps cure most cases of Hodgkin’s disease.

Plants like the periwinkle have contributed to the development of 25 to 50 percent of all prescription drugs used in the United States, either directly or by providing biochemical models, or templates, used to make synthetic compounds. Digitalis, which is used to treat chronic heart failure, comes from the leaves of the foxglove plant, and ephedrine, a component of many commonly prescribed respiratory medicines, is derived from a chemical formula from the ephedra plant. But overall, in the past 40 years there has been little development of new plant-based pharmaceuticals. During that period the U.S. Food and Drug Administration (FDA) approved fewer than a dozen drugs derived from plants.

Part of the reason is simply bottom line. The development of a new FDA-approved drug costs as much as 500 million U.S. dollars. Manufacturers have found the route from plant to safe, reliable pill difficult and unpredictable, so there is limited incentive to base drug development on plants. Still, almost two-thirds of the Earth’s 6.1 billion people rely on the healing power of plants; for them nothing else is affordable or available. And even in industrialized countries where scientifically formulated drugs are readily available—Americans spent 103 billion dollars on retail prescription drugs in 1998—use of nonprescription botanical drugs is rising dramatically. In 1990, 2.5 percent of Americans purchased herbal remedies; in 1997, 12.1 percent spent roughly five billion dollars on them.

What part of that money was spent wisely is a matter of some debate. While many plants have been the subject of extensive study and their effects well documented, data on others are inconclusive. Scientists are often unable to determine which chemical or combination of chemicals within a plant is responsible for relieving pain or stimulating blood flow or creating a feeling of increased well-being. Trying to find the part of a plant that has a specific effect can be like disassembling a radio to search for the one part that makes the sound.

Certain claims—“Guaranteed Better Health: only $5.00!”—in a proliferating number of special interest publications may well be false. No one knows, furthermore, to what extent the placebo effect is at play: Sometimes people want natural remedies to make them feel better, so they take them and feel better whether or not the substance had any effect.

Nonetheless, that plants contain bioactive chemicals, many with beneficial medicinal effects, is undeniable. Arnold Relman, editor in chief emeritus of the New England Journal of Medicine, who has attacked various forms of alternative medicine for being based on “irrational or fanciful thinking” or on theories that “violate basic scientific principles,” says that therapy based on botanical products need not be in fundamental conflict with mainstream medicine. “Many plant-derived materials,” says Relman, “have been proved to have important biological effects.”

Relman insists on scientific testing before he’ll believe in an herbal remedy, but people use hundreds of plants, not all of which have been tested by science, to combat ailments ranging from cancer to colds. Echinacea, an herb taken in tablet or liquid form, activates phagocytes—white blood cells that ingest bacteria and viruses. It can be effective in fighting flu, herpes, and yeast infections. Garlic contains allicin, a chemical that has antibiotic and antifungal effects, as well as compounds that can lower cholesterol and combat hypertension. Ginger contains at least 10 antiviral compounds, and studies have shown that it reduces vertigo and motion sickness. Chemicals in goldenseal, an herb of the buttercup family, kill certain bacteria, fungi, and protozoans.

* * *

One of the world’s leaders in the quest [for herbal remedies] is Jim Duke, a botanist who recently retired from the U.S. Department of Agriculture after three decades of studying medicinal plants. He’s the author of The Green Pharmacy and Herbs of the Bible: 2000 Years of Plant Medicine.

In Duke’s medicinal garden in rural Maryland hundreds of plants carpet a hillside sloping down to a creek. Some of the plants are more than ten feet [three meters] tall, others crawl along the ground; some are brightly colored, others drab. Bees and butterflies, along with the scents of apple, licorice, and mint, fill the air.

As Duke described the plants, I realized that untapped plant power abounds everywhere. Seeds of the milk thistle, a weed that grows in many backyards, contain silymarin, a compound that helps prevent toxins from entering the human liver.

“Come down to the catacomb,” Duke said, leading me into his book-filled basement. “I wish we could get the spiritual connection to plants that shamans have,” said Duke, “but in some ways we know a lot more. We have studies and evidence. Not romantic views of how nature works but hard facts.”

As we flipped through his computerized data bank, Duke talked about how isoflavones in soybeans may fight breast cancer; how angelica contains compounds that cause smooth-muscle cell walls to relax, reducing chest pain, or angina, caused by atherosclerosis; and how the kava rhizome contains compounds used as numbing agents or as sedatives.

One of Duke’s missions is to gather data to help overcome the resistance to plant remedies. I told him about a woman who suffers from severe arthritis. The medicine she takes for pain causes bleeding and shortness of breath. A friend suggested various botanicals, but the woman refused to try plants or herbs. “They’re not scientific or medical,” she said. She wanted a pill.

Duke pointed out that if a little white pill could significantly cut chances of developing cancer, having a heart attack, or suffering from a stroke, people would take it, especially if it had no side effects. In fact, he said, this “pill” already exists. It’s called “eating fruits and vegetables every day.” Scientists have started to identify the antioxidants, detoxifiers, hormone regulators, and other substances in food that cut the risk of various diseases.

“We can merge science with herbalism,” Duke said. “This will give us better drugs than if we rely on manufactured drugs alone. We can use science to test plants, to find what works best. The issue is not nature versus science; rather it is how to use science to get the best medicine, be it natural or synthetic.

“My life’s ambition,” said Duke, “is to get the FDA to require drug companies to test their new synthetic drugs not only against inactive substances, or placebos, but also against any known or suspected herbal alternative. We can have what plants offer without leaving the scientific method.

Back in Duke’s garden I spotted what appeared to be a common weed and bent to pull it up. “Please don’t,” Duke said. The plant was chicory, which contains chicoric acid—a chemical that shows promising activity against the virus associated with AIDS.

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