Evaluation of antioxidant potential of Emblica officinalis and Murraya koenigii and their role in modulation of cognitive function in diabetic rats

Abstract

Background: Hyperglycaemia and hyperlipidaemia seen in diabetes mellitus result in oxidative stress and pose significant risk of cognitive decline that may lead to Alzheimer’s disease. Approved anti-diabetic drugs have so far failed to demonstrate anti-oxidant and anti-hyperlipidemic activity, apart from saroglitazar. Therefore, this study was done to find a suitable anti-diabetic drug that possesses anti-hyperglycaemic, anti-oxidant and anti-hyperlipidemic activities and can reverse cognitive decline.Methods: Emblica officinalis (250 mg/kg, p.o. and 500 mg/kg, p.o.) and Murraya koenigii (250 mg/kg, p.o. and 500 mg/kg, p.o.) were chosen to study these activities in Wistar rats. Diabetes was induced by single intraperitoneal injection of streptozotocin [STZ] (50 mg/kg). Fasting blood glucose levels and lipid profile were measured on day 1 and day 30 of the experiment. Cognitive function was assessed by measuring transfer latency (TL) on elevated plus maze, step-down latency (SDL) on passive avoidance apparatus and retention latency (RL) and quadrant time (QT) in Morris water maze. Oxidative stress was assessed at end of study by measuring brain MDA and GSH levels. Cholinergic marker of cognition, AChE was measured in brain at end of study.Results: Both E. officinalis and M. koenigii showed dose dependent anti-hyperglycemic, anti-hyperlipidemic and anti-oxidant effects in diabetic rats with 500 mg/kg dose showing significantly higher effect. Both 250 mg/kg and 500 mg/kg dose of E. officinalis and M. koenigii partially reversed cognitive decline in diabetic rats by day 30.Conclusions: 500 mg/kg p.o. dose of E. officinalis or M. koenigii has potential to reverse cognitive decline in diabetic patients.