Memory-Improving Activity of the Flower Extract from Chrysanthemum boreale (Makino) Maskino in Scopolamine-Treated Rodents

One of the factors related to the pathogenesis of Alzheimer’s disease, a disease characterized by gradual cognitive and memory impairment, is an inflammatory process induced by the amyloid-β-mediated activation of microglia. In the present study, an extract of the Chrysanthemum boreale (Makino) Makino (CB) flower, which has inhibitory effects on inflammation and the production of phosphorylated tau in cells, was investigated for its ameliorative effect on memory dysfunction in scopolamine-treated Alzheimer’s disease models. The CB-extract-diet-administered groups, which were treated chronically with scopolamine (intraperitoneal), showed increased spontaneous alterations (12.5–15.5% increase) in the Y-maze test and latency to escape (3.7–6.7-fold increase) in the passive avoidance test, compared to the negative control (NC) group. Rats administered the CB extract also showed a higher tendency (66–86% increase) of hippocampal brain-derived neurotrophic factor expression than NC rats. Moreover, the ratio of phosphorylated extracellular signal-regulated kinase/extracellular signal-regulated kinase in the CB-extract-administered group was lower (48.0–52.2%) than that (100%) in the NC group. In the Morris water maze test conducted on the fifth day, the free-swimming times of the CB-extract-administered mice that were also treated with scopolamine for a short time (5 d) increased (51.7–56.1%) significantly compared to those of the NC mice. Finally, high-performance liquid chromatography analysis confirmed that isochlorogenic acid A, linarin, and chlorogenic acid are the major phenolic components of the CB extract. These results suggest that the extract of CB flowers might be useful as a functional material with memory-enhancing effects.