Protective effect of L-Theanine against aluminium induced neurotoxicity in cerebral cortex, hippocampus and cerebellum of rat brain - histopathological, and biochemical approach.

L-Theanine is an amino acid derivative primarily found in tea. It has been reported to promote relaxation and have neuroprotective effects. The present study was designed to investigate the role of oxidative stress and the status of antioxidant system in the management of aluminum chloride (AlCl3) induced brain toxicity in various rat brain regions and further to elucidate the potential role of L-Theanine in alleviating such negative effects. Aluminium administration significantly decreased the level of reduced glutathione and the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, Na(+)/K(+) ATPase, Ca(2+) ATPase and Mg(2+) ATPase and increased the level of lipid peroxidation and the activities of alkaline phosphatase, acid phosphatase, alanine transaminase and aspartate transaminase in all the brain regions when compared with control rats. Pre-treatment with L-Theanine at a dose of 200 mg/kg b.w. significantly increased the antioxidant status and activities of membrane bound enzymes and also decreased the level of LPO and the activities of marker enzymes, when compared with aluminium induced rats. Aluminium induction also caused histopathological changes in the cerebral cortex, cerebellum and hippocampus of rat brain which was reverted by pretreatment with L-Theanine. The present study clearly indicates the potential of L-Theanine in counteracting the damage inflicted by aluminium on rat brain regions.