Ameliorating effect of a herbal medicinal prescription, Kyung-Ok-Ko, on scopolamine-induced memory impairment in mice

Abstract

Kyung-Ok-Ko (KOK) which is widely used as a tonic in traditional Korean herbal medicine, and contains six main ingredients, such as, Ginseng Radix, Rehmanniae Radix, Hoelen, Honey, Lycium Fructus, and Aquilaria Lignum. In the present study, we assessed the effect of KOK on the learning and memory impairments induced by scopolamine in mice. The ameliorating effect of KOK was investigated using passive avoidance, Y-maze, and Morris water maze tasks. Drug-induced amnesia was introduced by administering scopolamine (1 mg/kg, i.p.). KOK (1 or 2 g/kg, p.o., single treatment 30 min before scopolamine) significantly prevented scopolamine-induced cognitive impairments in the passive avoidance task and the Y-maze task (p < 0.05), and improved escape latency in the Morris water maze task at 1 g/kg (p < 0.05). Moreover, KOK was also found to inhibit acetylcholinesterase activity in a dose-dependent manner in vitro (IC₅₀ value; 162 μg/ml), and to inhibit it ex-vivo. These results suggest KOK may be a useful treatment for cognitive impairment, and that its beneficial effects are mediated, in part, by enhancing the cholinergic neurotransmitter system.