Reversal of diabetes-induced behavioral and neurochemical deficits by cinnamaldehyde

Background: Chronic hyperglycemia during diabetes is associated with altered cognitive function. Cinnamaldehyde showed to have many pharmacological activities indicating anti-diabetic, cognitive enhancer, antiinflammatory etc. In the present study, we have investigated the effects of cinnamaldehyde (CA) on diabetes-induced cognitive deficits. Methods: Diabetes was induced in Sprague Dawley rats using high fat diet followed by streptozotocin (35 mg/kg, i.p.). High fat diet feeding was continued for 18 week after STZ administration. CA was administered daily during the last 3 weeks (week 16-18) at a doses of 10, 20 and 40 mg/kg (p.o.). Animals were subjected to behavioral tests during 18th week. Neurotransmitter levels (glutamate and GABA), acetylcholine esterase (AChE) activity and inflammatory markers (TNF-alpha and IL-6) were assessed in the hippocampus and cortex. Results: Vehicle-treated diabetic rats showed impaired behavior in open field, elevated plus maze and water maze test compared to age-matched control rats. Cinnamaldehyde showed significant reduction in blood glucose levels at dose of 20 and 40 mg/kg. Three weeks treatments of cinnamaldehyde showed significant amelioration of behavioral deficits in diabetic rats. Chronic treatment with cinnamaldehyde showed improvement in brain ChE activity, neurotransmitter levels and reduction in IL-6 and TNF-alpha levels. Conclusion: The present study demonstrates that treatment with cinnamaldehyde reverse neuroinflammation and changes in neurotransmitter levels, and consequently improves behavioral deficits in diabetic rats. (C) 2016 Elsevier GmbH. All rights reserved.