Inhibitory effect of an ethanol extract mixture of Aralia\n elata leaf, Chaenomeles sinensis fruit and\n Glycyrrhizae radix on Aβ\n (25–35)-induced memory impairment

Abstract

The young shoots of Aralia elata, Chaenomeles sinensis fruit and Glycyrrhizae radix are edible and traditionally used as anti-inflammatory and antioxidant agents. The present study was performed to investigate the protective effect of an ethanol extract mixture of these three medicinal plants (ACG) against amyloid β protein (Aβ) (25– 35)-induced memory impairment in an ICR mouse model. Memory impairment was induced by intracerebroventricular microinjection of 15 nmol Aβ (25–35) and assessed using the passive avoidance test and the Morris water maze test. The step-through latency in the passive avoidance test was decreased and the latency to reach the hidden platform in the Morris water maze test was increased in mice treated with Aβ (25–35), indicating memory impairment. This memory impairment induced by Aβ (25–35) was significantly prevented by chronic treatment with ACG (10, 25, and 50 mg/kg, p.o., 8 days). In memory impaired mice brain, cholinesterase activity and concentration of thiobarbituric acid reactive substance, a lipid peroxidation marker, were increased and glutathione level was decreased. These biochemical changes in Aβ (25–35)-treated mice were reversed by chronic administration of ACG. The present results suggest that antioxidant and anti-cholinesterase activities of ACG might be responsible for the inhibition of Aβ (25– 35)-induced memory impairment and that ACG preparation may have a therapeutic role in preventing the progression of Alzheimer’s disease.