Deoxyschizandrin Isolated from the Fruits of Schisandra chinensis Ameliorates Aβ1-42-induced Memory Impairment in Mice

In the present study, we examined the effects of deoxyschisandrin (DS) from Schisandra chinensis on the amyloid-beta(1-42) (A beta(1-42))-induced memory impairment in mice and investigated the possible antioxidative mechanism. Mice were given an intracerebroventricular (i.c.v.) injection with the aggregated A beta(1-42) and then treated with DS (4, 12, and 36 mg/kg body weight) or donepezil (DPZ), a positive control drug (0.65 mg/kg), by intragastric infusion for 14 days. Non-cognitive disturbances and cognitive performance were evaluated by the locomotor activity, Y-maze, and water maze tests. Antioxidative enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and levels of malondialdehyde (MDA), glutathione (GSH), and oxidized glutathione (GSSG) within the cerebral cortex and hippocampus of mice were measured to investigate the mechanism. Our results showed that DS significantly improved A beta(1-42)-induced short-term and spatial memory impairments in the Y-maze and water maze tests. Furthermore, in the cerebral cortex and hippocampus of mice, the reduced activities of SOD and GSH-px, the GSH level, and the GSH/GSSG ratio were increased, and increased levels of MDA and GSSG were reduced following treatment with DS, although the improvement of GSH and the reduction of GSSG levels were not marked. These results suggest that DS is a potential cognitive enhancer in Alzheimer's disease through its antioxidative action.