April 27, 2007

Hunt for medicines in nature probed at pharmacology forum

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Yuxiang Zheng, right, discusses her poster with fellow graduate student Juan Xing at last week’s Student-Invited Pharmacology Forum. (photo by Susan Urmy)

Hunt for medicines in nature probed at pharmacology forum

From the cloud forests of Costa Rica to the ocean depths off the coast of Florida, speakers at last week's Joel G. Hardman Student-Invited Pharmacology Forum are searching for new therapeutics.

The forum, in its 16th year, focused on the discovery and use of natural products in medicine.

Finding medications among natural products is not a new idea — Sumerian writings from about 3000 B.C. mention medicinal plants. And many drugs in use today had their origins in plants. The idea now, forum speakers told the audience, is to mine Earth's rich biodiversity to find new drugs that fight bacterial infections, cancer and other diseases.

“There are estimated to be 250,000 species of higher plants in the Costa Rican tropical rainforests … and only about 15 percent of them have been examined for possible medicinal applications,” said William Setzer, Ph.D., professor and chair of Chemistry and a member of the Natural Products Group at the University of Alabama in Huntsville.

Setzer described his group's “scratch-and-sniff” prospecting method. For one month each year, members of his team collect samples from the cloud forest (a tropical high-altitude forest) around Monteverde, Costa Rica, largely based on the aromas released when the group members “scratch” the plant's surface.

In one instance, a nicked vine “smelled like pumpkin pie,” Setzer said. “We had to get that one.”

From the samples, the investigators make extracts, partially purify the extracts, and screen them for bioactivity against a panel of bacteria, fungi, viruses and human tumor cell lines. Their studies have turned up some interesting leads, which the group is now attempting to alter chemically to optimize bioavailability and tumor selectivity, Setzer said.

Shirley Pomponi, Ph.D., and colleagues don scuba gear or climb into a submersible vessel to collect marine plants and animals. There are nearly 300,000 described marine organisms and estimates of about the same number not yet described, she said.

“That biological diversity lays the groundwork for chemical diversity,” said Pomponi, president and CEO of the Harbor Branch Oceanographic Institution in Ft. Pierce, Fla. More than 14,000 novel chemical compounds have been identified from marine sponges, she noted. One of these, discodermolide, was discovered in a sponge she collected. It is currently in clinical trials as a cancer treatment.

Other speakers at the symposium were Jinhui Dou, Ph.D., a member of the Botanical Review Team in the U.S. Food and Drug Administration Center for Drug Evaluation and Research, and Norman Farnsworth, Ph.D., director of the University of Illinois-Chicago NIH Center for Botanical Dietary Supplements Research, which has an emphasis on botanicals that may be useful for treating the symptoms of premenstrual syndrome and menopause.

The annual forum is named for Joel Hardman, Ph.D., who served as chair of Pharmacology from 1975 to 1990 and established the department as a premier place for research and training in pharmacology. At the forum, Alan Brash, Ph.D., professor of Pharmacology, received the 2007 Faculty Teaching Award, and graduate students J. Scott Gruver and Xiaohui Yan were recognized with 2007 Student Teaching Assistant Awards.