Abstract
The ameliorative effect of medicarpin (MC) was investigated by animal behavioral experiments such as Morris water maze (MWM), Y-maze, and passive avoidance test (PAT), using scopolamine-induced cognitively impaired mice. The scopolamine (5 mg/kg), donepezil (5 mg/kg), and MC (5 and 15 mg/kg) were administered by intraperitoneal injection at a volume of 0.3 mL. In the MWM, the escape latency times of MC-treated groups were significantly decreased compared with the scopolamine-treated negative control, and times spent in the platform zone of MC-treated groups were increased dose-dependently. In the Y-maze, the zone alternations of the MC-treated group were increased to the level of the donepezil-treated positive control. In the PAT, the crossing times of MC-treated groups were significantly higher than those of the negative control with dose-dependency. On the other hand, the monoamine oxidase (MAO)-A, MAO-B, and acetylcholinesterase (AChE) activities, relating to cognitive functions, in hippocampus treated with MC were decreased. In addition, the AChE activity in SH-SY5Y cells was significantly decreased. In Western blots, phosphorylated cyclic adenosine monophosphate (cAMP) response element-binding protein (p-CREB), brain-derived neurotrophic factor (BDNF), phosphorylated protein kinase B (p-Akt), and dopamine D2 receptor (D2R) levels in the hippocampus were higher than those of the negative control. In addition, p-CREB, BDNF, p-Akt, and D2R levels in SH-SY5Y cells treated with MC were significantly increased. These results showed that MC ameliorated a cognitive function along with increased BDNF and D2R expressions, and they suggested that MC could be used for the treatment of neurological disorders such as Alzheimer’s disease and Parkinson’s disease.