Anti-amnesic effects of ODH in mice with scopolamine induced amnesia. Mice were orally preadministrated with tacrine (2 mg/kg), ursolic acid (2 mg/kg), ODH (100 or 200 mg/kg) for four weeks. Mice were injected with scopolamine (3 mg/kg) to induce amnesia except for a normal group. (a) Effect of ODH on escape latency by Morris water maze test. Values are expressed as the means ± SD. * p < 0.05, *** p < 0.001 vs. scopolamine treated control group. # p < 0.05 vs. positive control group; (b) effect of ODH on scopolamine-induced memory deficit by the passive avoidance test. Values are expressed as the means ± SD. * p < 0.05 vs. scopolamine treated control group. *** p < 0.001 vs. scopolamine treated control group. # p < 0.05 vs. positive control group. N: normal group, C: control group, P: tacrine treated positive control groups, U: ursolic acid treated groups, O100: ODH 100 mg/kg treated group, and O200: ODH 200 mg/kg treated group.