OBJECTIVE To investigates the effects of imperatorin on the oxidative stress in the cerebral cortex and hippocampus after focal cerebral ischemia/reperfusion injury.METHODS Transient focal cerebral ischemia/reperfusion model in male Sprague-Dawley rats was induced by 2 h middle cerebral artery occlusion followed by 24 h reperfusion.Imperatorin(1.25 and 2.5 mg·kg-1)or vehicle were administered intraperitoneally at 1,5 and 9 h after the onset of ischemia.At 24 h after reperfusion,the biomarkers of oxidative stress such as the levels of reactive oxygen species(ROS),lipid peroxidation products malondialdehyde(MDA),nitric oxide(NO)and total antioxidant capacity(T-AOC),the activities of inducible nitric oxide synthase(iN OS),superoxide dismutase(SOD)and catalase(CAT)in the cerebral cortex and hippocampus were observed.We also assessed the nuclear factor erythroid 2-related factor 2(Nrf2),heme oxygenase-1(HO-1),and the NAD(P)H-quinone oxidoreductase 1(NQO-1)protein expression by Western blot.RESULTS As compared to vehicle-treated animals,imperatorin treatment significantly reduced the ROS,MDA,NO levels and i NOS activity,increased T-AOC and the activities of SOD and CAT.Furthermore,imperatorin treatment also significantly induced the nuclear translocation of Nrf2,enhanced the protein expression of HO-1 and NQO-1 in the cerebral cortex and hippocampus.CONCLUSION Our findings indicate that imperatorin can protect the brain against the excessive oxidative stress induced by cerebral ischemia/reperfusion through activation of Nrf2 signaling pathway. OBJECTIVE To investigates the effects of imperatorin on the oxidative stress in the cerebral cortex and hippocampus after focal cerebral ischemia / reperfusion injury. METHODS Transient focal cerebral ischemia / reperfusion model in male Sprague-Dawley rats was induced by 2 h middle cerebral artery occlusion followed by 24 h after reperfusion, the biomarkers of oxidative stress such as the levels of reactive (1.25 and 2.5 mg · kg-1) or vehicle were administered intraperitoneally at 1,5 and 9 h after the onset of ischemia. (ROS), lipid peroxidation products malondialdehyde (MDA), nitric oxide (NO) and total antioxidant capacity (T-AOC), the activities of inducible nitric oxide synthase (iNOS), superoxide dismutase (SOD) and catalase ) in the cerebral cortex and hippocampus were observed. We also assessed the nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and the NAD (P) H- quinone oxidoreductase 1 1) protein expression by Western blot .RESULTS As compared to vehicle-treated animals, imperatorin treatment significantly reduced the ROS, MDA, NO levels and i NOS activity, increased T-AOC and the activities of SOD and CAT.Furthermore, imperatorin treatment also significantly induced the nuclear translocation of Nrf2 , enhanced the protein expression of HO-1 and NQO-1 in the cerebral cortex and hippocampus. CONCLUSION Our findings indicate that imperatorin can protect the brain against the excessive oxidative stress induced by cerebral ischemia / reperfusion through activation of Nrf2 signaling pathway.