Antiamnesic effect of stevioside in scopolamine-treated rats

The present study was undertaken to explore the potential of stevioside in memory dysfunction of rats. Memory impairment was produced by scopolamine (0.5 mg/kg, i.p.) in animals. Morris water maze (MWM) test was employed to assess learning and memory. Brain acetylcholinestrase enzyme (AChE) activity was measured to assess the central cholinergic activity. The levels of brain thiobarbituric acid-reactive species (TBARS) and reduced glutathione (GSH) were estimated to assess the degree of oxidative stress. Scopolamine administration induced significant impairment of learning and memory in rats, as indicated by a marked decrease in MWM performance. Scopolamine administration also produced a significant enhancement of brain AChE activity and brain oxidative stress (increase in TBARS and decrease in GSH) levels. Pretreatment of stevioside (250 mg/kg dose orally) significantly reversed scopolamine-induced learning and memory deficits along with attenuation of scopolamine-induced rise in brain AChE activity and brain oxidative stress levels. It may be concluded that stevioside exerts a memory-preservative effect in cognitive deficits of rats possibly through its multiple actions.