Friday, October 10, 2008

Gingko & Stroke

Today, Oct. 10, 2008, Tara Parker-Pope informs us in a post under her New York Times health column Well on recent research suggesting that Ginkgo tree extracts may reduce brain damage after stroke. The study is published in the journal Stroke. The researchers affiliated with Johns-Hopkins University and La Fondation Ipsen temporarily blocked the middle cerebral artery in mice to induce an ischemic stroke. In mice treated with Ginkgo extract, the volume of brain tissue affected by the stroke was only about half that observed in untreated mice. The extract had no effect in mice that lacked heme oxygenase 1, an enzyme known to reduce oxidative stress caused by free radicals. These findings may encourage further basic research, ultimately opening a path for future pre-clinical and clinical trials.

I developed a liking for Ginkgo trees ever since I saw my first one on a high school visit to Heidelberg. The tree stood in the park outside the castle, solemnly holding its own one of a kind. They are not native to Germany. A lord long gone had purchased a seedling from China and planted it as a curiosity.

Ginkgo biloba is a species of ancient plants. Herbivorous dinosaurs already dieted on their broad leaves. The leaves are misleading. The trees are more closely related to conifers than to broad-leafed trees. Ginkgos are abundant in the Southeastern United States where I live. The leaves add a wonderful bright yellow to the panoply of foliage colors in the fall.

The leaves' peculiar shape caught the eye of the eminent German poet scientist J.W. von Goethe two centuries ago. Eternalized in a remarkable poem, Goethe calls to our attention the fact that the observer cannot tell from the leaves' shape whether they constitute one leaf split into two or two leaves fused into one. I quote "...Eins und doppelt bin."

This notion of ambiguity applies immediately to the discussed stroke research. As long as we do not know precisely which substances in the Ginkgo extract affect the ischemic brain tissue and what underlying molecular mechanisms reduce the impact of the stroke, medication with Ginkgo extracts is ill-advised. Particular prudence should be exercised, because the extracts are known to diminish blood clotting, exposing patients on blood thinners to additional risk.

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