Protective effects of pseudoginsenoside-F-11 on scopolamine-induced memoryimpairment in mice and rats

This study assessed the effects of pseudoginsenoside-F-11, a component of P anax quinque-folium L., on scopolamine-impaired memory performance in mice and rats. In the one-trial step-down and step-through passive avoidance tests, althou gh pseudoginsenoside-F-11 used alone did not affect passive avoidance behav iour in naive mice, the latency of avoidance shortened by intraperitoneal s copolamine (2 mg kg(-1)) was prolonged after intragastric administration of pseudoginsenoside-F-11 (2 or 4 mg kg(-1), for five days) in both test syst ems in mice. In the water-maze test, in mice, the time taken to locate the platform after administration of pseudoginsenoside-F-11 was shorter than th at after administration of scopolamine (1 mg kg(-1), i.p.). In the two-way active avoidance response test, the latency of avoidance was significantly shorter for the pseudoginsenoside-F-11- (1 2 or 2.4 mg kg(-1), i.g. for fiv e days) and scopolamine-treated group than for the group of rats given scop olamine only (2 mg kg(-1), i.p.). The percentage avoidance was also reduced after intraperitoneal injection of scopolamine, but was reversed by admini stration of pseudoginsenoside-F-11. These results suggest that pseudoginsenoside-F-11 antagonized the memory dy sfunction induced by scopolamine. However, the mechanism of the memory faci litative action of pseudoginsenoside-F-11 merits further elucidation.