Protective effects of pseudoginsenoside-F11 on scopolamine-induced memory impairment in mice and rats.

This study assessed the effects of pseudoginsenoside-F11, a component of Panax quinquefolium L., on scopolamine-impaired memory performance in mice and rats. In the one-trial step-down and step-through passive avoidance tests, although pseudo-ginsenoside-F11 used alone did not affect passive avoidance behaviour in naive mice, the latency of avoidance shortened by intraperitoneal scopolamine (2 mg kg(-1)) was prolonged after intragastric administration of pseudoginsenoside-F11 (2 or 4 mg kg(-1), for five days) in both test systems in mice. In the water-maze test, in mice, the time taken to locate the platform after administration of pseudoginsenoside-F11 was shorter than that 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-F11-(1.2 or 2.4 mg kg(-1), i.g. for five days) and scopolamine-treated group than for the group of rats given scopolamine only (2 mg kg(-1), i.p.). The percentage avoidance was also reduced after intraperitoneal injection of scopolamine, but was reversed by administration of pseudo-ginsenoside-F11. These results suggest that pseudoginsenoside-F11 antagonized the memory dysfunction induced by scopolamine. However, the mechanism of the memory facilitative action of pseudoginsenoside-F11 merits further elucidation.