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Objectives:Present study evaluates the effect of Calotropis procera (Apocynaceae) dry latex on cognitive function in rats using scopolamine and electroconvulsive shock (ECS) induced amnesia model.Materials and Methods:Male Wistar rats were pretreated with 200, 400 and 800 mg/kg of C. procera dry latex in scopolamine-induced amnesia model. Dose showing maximum effect in cognitive performance was selected and further evaluated using scopolamine and ECS-induced amnesia model for its effect on neurochemical enzymes and cognitive performance. Acetylcholinesterase (AChE) activity, β amyloid1-42, and dopamine level were analyzed, while the cognitive performance was assessed by elevated plus maze, step-through passive avoidance test, and Morris water maze. Simultaneously, C. procera dry latex (25, 50, 100, 250, 500, and 1000 μg/mL) was screened for in vitro AChE inhibition assay.Results:Pretreatment with (200, 400 and 800 mg/kg) C. procera dry latex shows dose dependent increase in cognitive performance in scopolamine-induced amnesia. Further, pretreatment with the selected dose (800 mg/kg) showed significant improvement in transfer latency (P < 0.001, P < 0.01), escape latency (P < 0.05), time spent in target quadrant (P < 0.001) also significant decrease in AChE activity (P < 0.05), β amyloid1-42 level (P < 0.001), and increase in dopamine level (P < 0.01) in rat brain homogenate when compared with scopolamine and ECS disease control groups. IC50 for C. procera dry latex was found to be <1000 μg/mL.Conclusions:Pretreatment with C. procera dry latex (800 mg/kg) produced significant cognition enhancement by improving cognitive performance and decreasing the marker neurochemical enzyme activity in scopolamine and ECS-induced amnesia model.

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Objective: Present study investigates the effect of ethanolic C. tora leaves extract on cognitive function in scopolamine and electroshock induced amnesia in rats. Methods: To explore the potential effect, C. tora extract was screened by administrating three doses (100, 200 and 400 mg/kg) for 14 days using scopolamine-induced amnesia model. The dose having maximum activity was selected (400 mg/kg) and evaluated by scopolamine and electroshock induced amnesia model, cognition parameters assessed using elevated plus maze, passive avoidance and Morris water maze. The biochemical parameters such as AChE and β amyloid 1-42 level from brain homogenate were estimated on 15 th day. In vitro acetylcholinesterase microplate assay of C. tora extract at 25, 50, 100, 250 and 500 µg/ml concentration was performed. Results: C. tora extract (400 mg/kg) showed increase in escape latency (p<0.001) and time spent in target quadrant (p<0.05) while decrease in transfer latency (p<0.001) was observed in scopolamine induced amnesia. Further, pre-treatment with C. tora (400 mg/kg) significantly reversed the behavioral impairment in scopolamine and electroconvulsive shock induced amnesia also AChE activity (p<0.001) and β amyloid1-42 level (p<0.001) were significantly decreased and IC 50 of C. tora extract was found out to be 198.59 µg/ml. Conclusion: Above finding concludes that ethanolic C. tora leaves extract possesses cognition enhancing property in scopolamine and electroshock induced amnesia models.

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