Back to Roots; January 1993; Scientific American Magazine; by Gary Stix; 2 Page(s)

From cocaine to quinine, about one quarter of U.S. prescription drugs contain at least one compound derived from plants. Yet in recent years plants lost their cachet at the big pharmaceutical firms as new ideas came from microbes or variants gleaned from huge data bases of synthetic chemicals. Now drug companies are emphasizing their roots. Botanists are once again avidly scouring the world's fields and forests to locate plant sources for new drugs. "Synthetics haven't proven to be the panacea," observes Mark J. Plotkin of Conservation International, a Washington, D.C.-based group that is working to stop destruction of tropical forests. "There's still no cure for AIDS or the common cold."

The lure is twofold: a "green" public relations boon and the prospect of discovering the next taxol, a treatment for ovarian cancer that was originally extracted from the bark of the relatively rare Pacific yew tree. Botanists estimate that 10 percent or less of the more than 250,000 flowering plant species have been surveyed for pharmacological activity. But the task of finding an active molecule in a haystack is being eased by devices that can quickly search through tens of thousands of samples.