Korean red ginseng saponins with low ratios of protopanaxadiol and protopanaxatriol saponin improve scopolamine-induced learning disability and spatial working memory in mice

The effects of two ginseng saponins having a different ratio of protopanaxa diol (PD) and protopanaxatriol saponins (PT on the learning impairment indu ced by scopolamine, and learning and memory in mice were investigated in a passive avoidance task and a Morris water maze task. The ratio of PD and PT was 1.24 and 1.46, respectively. Before training, the ginseng saponins wer e administered intraperitoneally at doses of 50 and 100 mg/kg. The two sapo nins improved the scopolamine-induced learning impairment at different dosa ges in mice, 50 and 100 mg/kg, respectively. However, the two saponins did not show a favorable effect on]learning and memory in normal mice. Korean r ed ginseng saponin with a low PD/PT ratio had an improving effect on spatia l working memory, but the saponin with a high PD/PT ratio did not. This fin ding suggests that the PD/PT ratio of the ginseng saponins may be an import ant factor in the pharmacological role of red ginseng as a medicinal herb. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.