Research Article Memory-Enhancing Effects of the Crude Extract of Polygala tenuifolia on Aged Mice

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Learning and memory disorders arise from distinct age-associated processes, and aging animals are often used as a model of memory impairment. The root of Polygala tenuifolia has been commonly used in some Asian countries as memory enhancer and its memory improvement has been reported in various animal models. However, there is less research to verify its effect onmemory functions in aged animals. Herein, the memory-enhancing effects of the crude extract of Polygala tenuifolia (EPT) on normal aged mice were assessed by Morris water maze (MWM) and step-down passive avoidance tests. In MWM tests, the impaired spatial memory of the agedmice was partly reversed by EPT (100 and 200mg/kg; P < 0.05) as comparedwith the aged controlmice. In step-down tests, the nonspatial memory of the aged mice was improved by EPT (100 and 200mg/kg; P < 0.05). Additionally, EPT could increase superoxide dismutase (SOD) and catalase (CAT) activities, inhibit monoamine oxidase (MAO) and acetyl cholinesterase (AChE) activities, and decrease the levels of malondialdehyde (MDA) in the brain tissue of the aged mice. The results showed that EPT improved memory functions of the aged mice probably via its antioxidant properties and via decreasing the activities of MAO and AChE. 1