An extract from the leaves of the Gingko biloba tree can stabilize and even improve dementia for up to one year. Researchers in New York and Boston found the extract stabilized or improved cognitive function and social behavior in patients with moderate to severe Alzheimer's disease or multi-infarct dementia, a form of vascular dementia, for six months to one year.
Various extracts of Gingko biloba have been used in Chinese medicine since ancient times as an herbal remedy for asthma and related respiratory ailments and for disorders of the brain. Herbal treatments are more widely accepted by physicians in Europe than in the United States. In Europe, the Gingko biloba extract called EGb 761 is used to treat a range of cognitive disorders. It has recently been approved in Germany for the treatment of dementia.
Although the mechanism of how it works remains unclear, the extract contains a number of compounds with antioxidant and anti-inflammatory properties. Some of these compounds may prevent molecular products of oxidation known as free radicals from causing damage to cells, including brain cells.
In the first placebo-controlled clinical trial of the extract conducted in the United States pills containing 40 milligrams of EGb 761 three times per day were given to a group of patients diagnosed with Alzheimer's disease or multi-infarct dementia. Another group received look-alike placebo pills. The researchers found that 27% of the patients taking Egb improved by at least four points on the ADAS-Cog scale, compared to 14% of those taking placebo.
Compared with the placebo group, the EGb group included twice as many patients whose cognitive performance improved and half as many whose social functioning worsened. In clinical terms, improvement on the ADAS-Cog of four points may be equivalent to a six-month delay in the progression of the disease. Regarding the safety profile of EGb, no significant differences compared with placebo were observed in the number of patients reporting adverse events.
Journal of the American Medical Association (1997;278:1327-1332)