Panax ginseng extract improves the scopolamine-induced disruption of 8-arm radial maze performance in rats.

The effects of Panax ginseng ethanol extract and its water (WSF)- and lipid-soluble (LSF) fractions on the scopolamine-induced disruption of radial maze performance in rats were examined. Ginseng root was refluxed with ethanol, and WSF and LSF were prepared from this ethanol extract. Scopolamine (0.075-0.3 mg/kg, i.p.) dose-dependently impaired the maze performance. However, the oral administration of Panax ginseng ethanol extract and WSF (2-8 g dried root/kg) 90 min before testing improved the maze performance disrupted by scopolamine (0.3 mg/kg) in a dose-dependent manner, but LSF failed to attenuate the disruption. These data suggest that ginseng extract possesses a beneficial effect regarding spatial cognitive impairment and that the water-soluble fraction of ginseng extract mainly contributes to the effect of the ethanol extract.