Effect of the antioxidant action of Ginkgo biloba extract (EGb 761) on aging and oxidative stress.

Abstract

Aging is responsible for oxidative damage to DNA, protein, lipid, and other macromolecules linked to tissue alterations. The resultant damage contributes significantly to degenerative diseases, to include those of the brain, sensorial tissues, and cardiovascular system. To protect cellular components from oxyradical attack, especially lipoperoxidation, a substantial interest in the use of antioxidants has evolved. A free radical scavenger, Ginkgo biloba extract (EGb 761) may be effective in fighting the oxidative stress related to aging. Many data support the efficacy of EGb 761 in biological model systems. In aging processes, EGb 761 may ameliorate the mitochondria respiratory chain function by quenching the superoxide anion, and the hydroxyl and peroxyl radicals. It protects the brain by facilitating the uptake of neurotransmitters and by reducing ischemia-reperfusion episodes and level of apoptosis. Moreover, in sensorial tissues, EGb 761 reduces apoptosis in the olfactive bulb and in the retinal pigmented epithelium of the eye, and protects against the lipoperoxidation alteration of the retina that results in a decrease of the electroretinogram response. In the cardiovascular system, by a direct effect on oxidative low density lipoproteins, EGb 761 may decrease atherosclerosis evolution, and is shown to accelerate cardiac mechanical recovery after ischemia-reperfusion. In conclusion, the antioxidant effects of EGb 761 noted in many experimental data, may explain the therapeutic efficacy observed in clinical trials of the elderly. These beneficial properties seem in part to come from the activity of EGb 761 constituents, such as flavonoids and terpens.