Protective Effects of Daidzein on Oxidative Stress-Induced Neurotoxicity and Scopolamine-Mediated Cognitive Defect

摘要

To investigate the effect of daidzein, a major isoflavone constituent isolated from Pueraria thunbergiana (an arrowroot), on the oxidative damage and the scopolamine-induced cognitive deficit, in vitro cell viability assays and in vivo behavioral tests were performed. Using 3 assays 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction, lactate dehydrogenase release, and trypan blue exclusion) daidzein showed cell protective effects on oxidative stress-induced cytotoxicity. Administration of daidzein to mice significantly reversed the scopolamine-induced learning and memory impairment in a passive avoidance test. Injection of scopolamine to mice impaired performance in the passive avoidance test (43% decrease). In contrast, mice treated with daidzein before scopolamine injection were protected from this change (higher than the control value). These results suggest that daidzein's neuronal cell protective activities reduce the scopolamine-induced cognitive deficit and that its anti-amnesic effect might be due to the activation of choline acetyltransferase.