CHAPEL HILL - After 12 years work, chemists at the University of North Carolina at Chapel Hill have succeeded in completely synthesizing ginkgolide B, a complex molecule produced naturally by what may be the world's oldest living plant.

"Ginkgolide B is isolated from the ginko tree, which Charles Darwin called a living fossil," said Dr. Michael T. Crimmins, professor of chemistry at UNC-CH. "The extracts have been used for thousands of years as herbal medicines and have been attracting a lot of attention recently. The complexity of the molecule caused us to change our approach several times, and that's why the synthesis required so much time."

The compound is one of the active ingredients in such commercial products as Ginkoba, touted by its manufacturer as being able to boost alertness and other mental functions, Crimmins said. The natural product currently is being tested in clinical trials for treating dementia, multiple sclerosis and other illnesses.

A report on the new work should appear in a chemistry journal in the fall, probably the Journal of the American Chemical Society, he said.

Female ginkgo trees, which date back about 250 million years, bear sticky, foul-smelling fruit, Crimmins said. Both male and female trees produce fan-shaped leaves with parallel veins unlike any other plant.

"Ginkgo extract has been used to treat coughs, allergic inflammations, circulatory disorders and other conditions in Asian cultures such as India and China," Crimmins said. "Recent, still-early studies have shown it apparently does have some effect in delaying the onset of Alzheimer's disease."

Ginkgolide B, which scientists call a platelet-activating factor antagonist, is the most active component of the extract in terms of helping treat asthma and other allergic responses, he said. Five or more ginkgolide-type molecules occur, but ginkgolide B also is one of the most complicated
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Contact: David Williamson
David_Williamson@unc.edu
919-962-8596
University of North Carolina at Chapel Hill
10-Jun-1999