Effect of Elettaria cardamomum hydroethanolic extract on learning and memory in Scopolamine induced amnesia

Abstract

Elettaria cardamomum, commonly known as green cardamom in traditional system of medicine has antibacterial, antioxidant, antiasthmatics and digestive properties. The present study was designed to assess the effect of hydroethanolic extract of Elettaria cardamomum fruit on learning and memory, brain cholinesterase levels and associated altered brain oxidative stress markers in scopolamine treated mice. The extract was administered orally in three doses (250, 500 and 1000 mg/kg p.o) for a period of 15 days. Piracetam, 500mg/kg p.o, was used as standard treatment. Scopolamine was administered in the dose of 1.0 mg/kg intraperitoneally. The Morris water maze and elevated plus maze were used to assess cognitive functions. At the end of the study, effect of extract was assessed on brain cholinesterase levels and oxidative stress markers like lipid peroxidation, reduced glutathione, catalase and superoxide dismutase in the brain tissue of mice. The Scopolamine-treated group (negative control) showed significantly impaired acquisition and retention of memory as compared to the saline treated group (vehicle control). Pre-treatment with Elettaria cardamomum extract (500 and 1000 mg/kg) for 15 days significantly reversed Scopolamine induced amnesia as evidenced by increased time spent in target quadrant in Morris water maze test and decreased transfer latency in elevated plus maze test compared to the negative control. Scopolamine administration caused significant increase in brain cholinesterase levels which were attenuated by Elettaria cardamomum treatment. Pre-treatment with Elettaria cardamomum extract (500 and 1000 mg/kg p.o.) resulted in a significant decrease in lipid peroxidation and increase in reduced glutathione, catalase and superoxide dismutase levels as compared to the negative control. These results suggest that Elettaria cardamomum may improve learning and memory of amnesic mice and this effect can be attributed to decreased oxidative stress and reduction in brain cholinesterase levels.