OBJECTIVE The abnormal amyloid-β(Aβ)and oxidative stress assiociated with the progression of Alzheimer disease(AD).Quercetin has been reported to possess antioxidant and anti-inflammatory properties in neurodegenerative disorders.In this present study,we designed to characterize the mechanisms by which quer-cetin exerts neuroprotective effects in murine neuroblas-toma N2a cells stably expressing human Swedish mutant amyloid precursor protein(N2a/APP).METHODS N2a/APP cells were treated with quercetin at concentrations of 10,20 and 50 μ mol·L-1 for 24 h.Cell viability was examined with CCK-8 assays.The protein levels of ERK1/2 and Akt were detected by Western blotting.Intra-cellular reactive oxygen species(ROS)was detected by a fluorescent probe 2,7-dichlorofluorescein diacetate(DCFH-DA).The mitochondrial membrane potential(Δψ m)in N2a/APP cells was detected by using JC-1 staining method.Immunofluorescence was used to detect the generation of 8-hydroxy-2′-deoxyguanosine(8-OHdG)and 4-hydroxynonenal(4-HNE).RESULTS Quercetin attenuated the enhancement of p-ERK1/2,reductions of p-Akt,and decreased levels of APP expression.More-over,quercetin alleviated loss of mitochondria membrane potential(MMP)since it attenuates these oxidative stress,as reflected in the levels of ROS,4-HNE and 8-OHdG,was elevated in N2a/APP cells and these effects were again ameliorated by quercetin.CONCLUSION Neuroprotection by quercetin in N2a/APP cells involves normalizing the impaired mitochondrial function and reducing oxidative stress via inactivation of the ERK1/2 and activation of the Akt pathways.