Yuk-Mi-Jihwang-Tang, a Traditional Korean Multiple Herbal Formulae, Improves Hippocampal Memory on Scopolamine Injection-Induced Amnesia Model of C57BL/6 Mice

We evaluated neuropharmacological properties of Yuk-Mi-Jihwang-Tang (YJT) against scopolamine injection-induced memory impairment mice model. Mice were orally administered with YJT (50, 100, or 200 mg/kg) or tacrine (TAC, 12.5 mg/kg) for 10 days. At the first day of Morris water maze task, scopolamine (2 mg/kg) was intraperitoneally injected before 30 min of it. The hippocampal memory function was determined by the Morris water maze task for 5 days consecutively. Scopolamine drastically increased escape latency and decreased time spent in target quadrant. Pretreatment YJT properly improved them. Regarding the redox status, YJT significantly reduced the oxidative stress and it also exerted much effort to improve both superoxide dismutase and catalase activities in hippocampal gene expression and protein levels. These effects were well coincided with immunohistochemical analysis of 4-hydroxyneal-positive signals in hippocampal areas. Additionally, acetylcholine esterase activities and brain-derived neurotrophic factor abnormalities in the hippocampal protein levels were significantly normalized by YJT, and their related molecules were also improved. The neuronal proliferation in hippocampal regions was markedly inhibited by scopolamine, whereas YJT notably recovered them. Collectively, YJT exerts much effort to enhance memorial functions through improving redox status homeostasis and partially regulates acetylcholine esterase activities as well as neuronal cell proliferation.