Friday, June 5, 2009

Gingko Extract Shown to Reduce Certain Chronic Pain

The June issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society reports today that an extract of ginkgo biloba shows scientific evidence of effectiveness against one common and hard-to-treat type of pain. Research has been conducted on rats, which is likely to hold true with humans as well.

Dr. Yee Suk Kim and colleagues of The Catholic University of Seoul (South Kore) performed experiments in rats to evaluate the effectiveness of ginkgo against neuropathic pain, a common pain problem associated with herpes zoster, limb injury, or diabetes. Affected patients may feel severe pain in response to harmless stimuli like heat, cold, or touch.

Rats with this same type of neuropathic pain were treated with different levels of a standardized ginkgo biloba extract or with an inactive solution as a placebo, and the tests were performed to see how ginkgo affected pain responses to cold and pressure. Pain responses were significantly reduced in the ginkgo-treated rats. The higher the dose of ginkgo extract, the greater the pain-relieving effect. Pain was reduced for at least two hours after ginkgo treatment.

Unfortunately, the study provides no evidence as to how ginkgo works to reduce pain. Several mechanisms are possible, including antioxidant activity, an anti-inflammatory effect, or protection against nerve injury—perhaps in combination.

Ginkgo, one of the most popular herbal products, is widely used as a memory enhancer, among other purposes. But it has not often been seen in the literature as a possible pain reliever. New treatments are needed for neuropathic pain, which does not always respond well to available treatments.

"It's still too early to stock up on ginkgo biloba if you have chronic pain," comments Dr. Steven L. Shafer of Columbia University. "Many treatments that are effective in animals do not prove to be effective in humans, or prove to have unacceptable toxic effects when given to patients" Dr. Shafer reminds.


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