The Neuroprotective Effect of Ginkgo biloba Leaf Extract and its Possible Mechanism

An extract from the leaves of the Ginkgo biloba tree, labeled EGb761, is one of the most widely used medicinal products in the West for cardiovascular and brain related diseases. In particular, it has been used frequently for the treatment and prevention of neurodegenerative diseases such as mild cognitive impairment or Alzheimer's disease. The drug is relatively safe and has been used widely by healthy individuals as an alternative medicine, even for anti-normal aging. EGb761 consists of two major substances, the flavone glycosides (flavonoid fraction, 24%) and the terpene lactones (terpenoid fraction, 6%), which might possess the function of neuroprotection. Possible mechanisms suggested include interactions with the mitochondria and apoptosis, platelet aggregation antagonism, free radicals and nitric oxide scavenging, modulation of neurotransmitters, and induction of growth factors. However, the mechanism of its therapeutic effect on the central nervous system remains inconclusive. In this review article, we will attempt to summarize the molecular evidence of the neuroprotective mechanism of Ginkgo, and to explain its possible neuroprotective effect on the central nervous system. By choosing a suitable biochemical marker, the neuroprotective effect of Ginkgo could be studied, quantified, and compared in different studies of the central nervous system as well as in other organ systems. This would lead to a better understanding of the mystified anti-aging role of Ginkgo in human.