Anti-oxidant, anti-inflammatory and anti-cholinergic action of Adhatoda vasica Nees contributes to amelioration of diabetic encephalopathy in rats: Behavioral and biochemical evidences

‘Diabetic encephalopathy’ refers to diabetes associated cognitive decline (DACD), which involves oxidative-nitrosative stress, inflammation and cholinergic dysfunction. Current study was designed to investigate the effect of Adhatoda vasica, a known anti-inflammatory, antioxidant, anti-cholinesterase and anti-hyperglycemic plant, on diabetic encephalopathy. Streptozotocin (STZ)-induced diabetic Wistar rats were treated with Adhatoda vasica leaves ethanolic extract (AVEE) for 6 weeks at 100, 200 and 400 mg/kg/day dose. During fifth week of treatment, learning and memory was investigated in single Y-maze and passive avoidance test. At the end of the study biochemical parameters like acetylcholinesterase (AchE) activity, nitrite levels, tumor necrosis factor-alpha (TNF-α) and oxidative stress was measured from cerebral cortex and hippocampus regions of brain. AchE activity was found increased by 70 % in the cerebral cortex of diabetic rat brain. Lipid peroxidation (LPO) levels were increased by 100 % and 94 % in cerebral cortex and hippocampus of diabetic rats, respectively. Non-protein thiol levels, enzymatic activities of superoxide dismutase and catalase were found decreased in cerebral cortex and hippocampal regions of diabetic rat brain. Nitrite levels in both regions of diabetic brain were increased by 170 % and 137 % respectively. TNF-α, a pro-inflammatory cytokine, was found significantly increased in diabetic rats. Conversely, animal groups treated with AVEE significantly attenuated these behavioral and biochemical abnormalities. The results suggest a protective role of Adhatoda vasica Nees against diabetic encephalopathy, which may be sum of its anti-oxidant, anti-cholinesterase, anti-inflammatory and glucose lowering action.