Traditional Korean herbal formulae, Yuk-Mi-Ji-Hwang-Tang, ameliorates impairment of hippocampal memory ability by chronic restraint stress of mouse model.

Ethnopharmacological Relevance: Yuk-Mi-Jihwang-Tang (YJT) has been popularly prescribed to treat aging related disorders over than hundreds of years in East Asia countries.
Aim of the Study: To investigate possible modulatory actions of YJT on chronic restraint stress (CRS)-induced neurodegeneration on hippocampus neuronal injuries.
Materials and Methods: Mice were orally administered with YJT (100, 200, or 400 mg/kg) or ascorbic acid (100 mg/kg) before 4 h of stress for 28 days. Morris water maze task was completed from day 24th to 28th, and stress hormones and biochemical analyzes were measured.
Results: Four weeks of the CRS abnormally affected memory impairments by measurement of escape latency and time spent in the target quadrant. Additionally, neurotransmitters were also drastically altered in serum or hippocampus protein levels by CRS. Gene expressions for 5-hydroxytryptamine (5-HT) receptor, 5-HT-transport, and tryptophan hydroxylase were also altered, whereas YJT led to normalize the above alterations. Additionally, YJT also beneficially worked on endogenous redox system as well as inflammatory reactions in the hippocampal neurons. We observed that hippocampal excitotoxicity was induced by CRS which were evidenced by depletion of phosphor-cAMP response element-binding protein, brain-derived neurotrophic factor, nuclear factor erythroid-2-related factor 2, heme oxygenase-1 and abnormally increases of acetylcholine esterase activities in hippocampus protein levels; however, YJT considerably improved the above pathological conditions.
Conclusions: Our findings supported YJT enhance memory function via regulation of hippocampal excitotoxicity-derived memory impairment, stress hormone, and endogenous redox, respectively.
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