October 10, 2008

Ginkgo Reduces Brain Damage Caused By Strokes

Scientists reported on Thursday a new study that shows daily doses of ginkgo extract could help reduce brain damage caused by a stroke.

Researchers at Johns Hopkins University in Baltimore gave mice daily doses of ginkgo biloba extract before having a stroke induced in the laboratory. Brain damage in these mice was cut almost in half compared to animals that did not receive the extract.

Mice who did not get ginkgo before a stroke but were given it five minutes after a stroke sustained nearly 60 percent less damage in the day after the stroke than those not given ginkgo. And mice given ginkgo 4-1/2 hours after a stroke had about a third less damage than those not given ginkgo, researchers wrote in the journal Stroke.

"We tested the concept of preventive medicine by giving ginkgo before stroke and we showed protection," said Sylvain Dore of Johns Hopkins, who led the study.

"And the other thing we showed is the potential therapeutic application of ginkgo. So it was given after the stroke and we also showed protection," Dore said.

Sometimes, a clot-busting drug called tissue plasminogen activator (tPA) can be used in patients within about three hours of a stroke, but tPA doesn't protect against the brain cell damage that occurs once blood flow is restored.

Researchers said ginkgo appears to raise levels of heme oxygenase-1, or HO-1, which is an enzyme that acts as an antioxidant to protect against cell damage from "free radicals" -- toxic oxygen molecules released by cells when they are under stress.

Ginkgo itself doesn't protect the brain against effects of a stroke. It works to produce the enzymes that do this.

The ginkgo is one of the oldest types of tree living on Earth, dating back at least 270 million years.

Ginkgo has been used as a medicine for centuries and remains a very popular herbal medicine. Some findings suggest it can improve cognitive function and decrease development of Alzheimer's disease symptoms. It is generally considered safe.


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