Ginkgo biloba neuroprotection: Therapeutic implications in Alzheimer's disease.

An extract of Ginkgo biloba leaves, EGb761, is becoming one of the most popular dietary supplements in the United States to enhance memory. In Europe it is a commonly prescribed drug for treatment of age-related deterioration, including degenerative dementias of the Alzheimer type (AD). Substantial experimental evidence indicates that EGb761 has neuroprotective potency under conditions such as ischemia, seizures and peripheral nerve damage. However, the mechanisms of such neuroprotective effects remain unknown, partially because of the complex chemical composition of EGb761 and the resulting so-called "polyvalent" action. This review focuses on cellular and molecular approaches towards understanding the polyvalent action of EGb761 neuroprotective effect. Two potential mechanisms of action, reducing oxidative damage and stimulating cell survival machinery, are discussed. Better understanding of the neuroprotective mechanisms of EGb761 will provide impetus for possible combination therapies and for the design of rational, "mechanism-based" strategies that target age-related neurodegeneration and Alzheimer's disease.