Antioxidant, anti-inflammatory and anticholinergic action of berberine attenuates diabetic encephalopathy: Behavioral and biochemical evidences

Abstract

Diabetic encephalopathy, characterized by impaired cognitive functions and neurochemical and structural abnormalities, involves direct neuronal damage caused by intracellular glucose. The present study was designed to investigate the effect of berberine an anti-oxidant and anti-inflammatory molecule, on cognitive functions, oxidative-nitrosative stress and inflammation in streptozotocin (STZ)-induced diabetic rats. STZ-induced diabetic Wistar rats were treated with berberine for 6 weeks at 50 and 100 mg/kg/day. 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 56 % in the cerebral cortex of diabetic rat brain. Lipid peroxidation (LPO) levels were increased by 100 % and 95 % in cerebral cortex and hippocampus of diabetic rats, respectively. Nonprotein 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 significantly (P < 0.05) compared to control group. TNF-α, a pro-inflammatory cytokine, was found significantly increased in diabetic rats. Conversely, animal groups treated with significantly attenuated these behavioral and biochemical abnormalities. The results suggest a protective role of berberine against diabetic encephalopathy, which may be sum of its anti-oxidant, anti-cholinesterase, anti-inflammatory and glucose lowering action.