Emerging epidemiologic data indicates that diabetes is a potential predisposing factor for neuropsychiatric deficits as stroke,
cerebrovascular diseases, diabetes-associated cognitive decline, depression and anxiety. Diabetes-associated cognitive decline,
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 sesamol (3,4-methylenedioxyphenol),
a phenolic antioxidant and anti-inflammatory molecule, on cognitive functions, oxidative stress and inflammation in diabetic
rats. Learning and memory behaviors were investigated using a spatial version of the Morris water maze test. Acetylcholinesterase
activity, a marker of cholinergic dysfunction, was increased by 80% in the cerebral cortex of diabetic rats. There was 107
and 121% rise in thiobarbituric acid reactive substance levels in cerebral cortex and hippocampus of diabetic rats, respectively.
Reduced glutathione levels and enzymatic activities of superoxide dismutase and catalase were decreased in both cerebral cortex
and hippocampal regions of diabetic rat brain. Nitrite levels in cerebral cortex and hippocampus was increased by 138 and
109%, respectively. Serum tumor necrosis factor-alpha, a marker for inflammation, was found to increase by 1,100% in diabetic
rats. Chronic treatment with sesamol (2, 4 and 8 mg/kg; p.o.) significantly and dose-dependently attenuated cognitive deficit,
reduced acetylcholinesterase, oxidative stress and inflammation in diabetic rats. The results emphasize the involvement of
oxidative stress and inflammation in the development of cognitive impairment in diabetic animals and point towards the therapeutic
potential of sesamol in diabetes-associated cognitive decline.
Keywords Acetylcholinesterase - Diabetes-associated cognitive decline - Oxidative stress - Sesamol - TNF-α