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Ginkgo Extracts Show Promise
By Sean Henahan, Access Excellence
 Washington, DC (October 22, 1997)- An extract of the plant
Ginkgo biloba, long used in Chinese medicine, appears to provide
some benefit for some patients with Alzheimer's disease, reported
clinical researchers at the American Medical Association's
16th Annual Science Reporters Conference.
Researchers from the New York Institute for Medical Research,
Tarrytown, N.Y., compared the effects of EGb 761, a particular
extract of Ginkgo biloba, and and placebo in a year-long,
double-blind study of 309 demented patients with mild to moderately
severe cognitive impairment caused by Alzheimer disease, vascular
dementia or a combination of the two.
The results indicated that EGb had a measurable effect on
cognitive impairment and daily living and social behavior
in patients with dementia. Although the treatment effect could
not be detected by the clinician's global impression of change,
it was demonstrated through objective tests of cognitive
performance and was strong enough to be noticed by caregivers.
A little more than one quarter of patients treated for at
least six months with EGb achieved at least a four point improvement
on the commonly used 70 point Alzheimer Disease Assessment
Scale-Cognitive subscale, compared with 14 percent taking
placebo. Another rating scale, the Geriatric Evaluation by
Relative's Rating Instrument (GERRI), showed improvement in
daily living and social behavior of 37 percent of the patients
taking EGb, compared with 23 percent 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. EGb
appears to stabilize and, in an additional 20 percent of cases
(vs. placebo), improve the patient's functioning for periods
of six months to one year. Regarding its safety, adverse events
associated with EGb were no different from those associated
with placebo," reported Pierre L. LeBars, M.D., Ph.D.
"Although it has a reasonably modest effect, it could be
meaningful to caregivers. To have a plateau for six months
and be able to interact with the person when they're still
at a relatively early stage is something that many families
would appreciate, I think," Marcelle Morrison-Bogorad, an
Alzheimer's disease researcher at the National Institute on
Aging at the National Institutes of Health, told the press.
Extracts from the Ginkgo biloba tree have long been used
in China for diseases associated with old age. The extract
of Ginkgo biloba used in this study, EGb 761, has recently
been approved in Germany for the treatment of dementia.
The researchers do not know how EGb exerts its neurological
effects. Ginkgo extracts contain antioxidants that may help
to protect cells against oxidative damage. Oxidative damage
has been seen in the brain cells of Alzheimer's patients.
Ginkgo extracts also contains compounds that act as vasodilators,
increasing blood flow. They also contain substances which
exert strong anti-platelet effects.
Gingko Shows Promise
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Used with permission of Sean Henahan
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