Anti-amnestic properties of Ginkgo biloba extract on impaired memory function induced by aluminum in rats

- Induction of brain toxicity using aluminum (Al) worsened memory in passive avoidance.
- Al induced elevation of aluminum brain content, serum aluminum level, AChE activity.
- Al increased brain contents of MDA, GSSG and depleted brain GSH content.
- Co-administration of Ginkgo biloba normalized brain MDA, GSSG, GSH and AChE activity.
- Ginkgo biloba improved memory in passive avoidance, had no effect on brain Al content.

Aluminum is the most widely used non-ferrous metal. However, recently it is reported to be a neurotoxic agent that could induce biochemical defects in brain by affecting levels of neurotransmitters and generating reactive oxygen species resulting in oxidative stress. This study aimed at evaluating neuroprotective effect of Ginkgo biloba extract2 (GBE) (200 mg/kg for 28 days) in antagonizing aluminum-induced neurotoxicity through investigating certain parameters such as serum aluminum level, brain aluminum content, brain regional distribution of aluminum, brain oxidative stress biomarkers' content, and brain acetylcholinesterase3 (AChE) activity. Passive avoidance paradigm was used to assess memory retrieval of rats. Rats' activities were studied using open field test. Results showed that administration of aluminum (10 mg/kg for 28 days) impaired rats' memory retrieval associated with marked elevation of aluminum brain content, serum aluminum level and AChE activity. In addition, aluminum treatment induced significant elevation in its brain content in all tested regions. GBE treatment attenuated neurotoxic effects of aluminum as evidenced by improving rats' performance in passive avoidance and lowering brain AChE activity. Moreover, marked elevation in brain content of oxidized glutathione4 (GSSG) and malonedialdehyde5 (MDA) as well as depletion of reduced glutathione6 (GSH) demonstrated following aluminum administration were reversed reaching normal levels after GBE treatment. Open field test, demonstrated no changes in latency period, number of ambulation, rearing, and grooming following aluminum or other treatments. Therefore, GBE may be a promising therapy ameliorating neurotoxicity of aluminum as an environmental toxic agent.