Abstract: To investigate the effects and mechanisms of imperatorin on learning and memory of beta-amyloid peptide_1-42 (Aβ_1-42)-induced model of Alzheimers disease (AD) in mice.Mice were injected with Aβ_1-42 intracerebroventricularly to induce AD model.Imperatorin (2.5,5mg/kg) were administered intraperitoneally once daily for 13 days,the normal control group and the AD model group were given the vehicle (0.1 mL/10 g) according to the same protocol.The learning and memory ability was evaluated by the step-down test,the contents of reactive oxygen species (ROS) and lipid peroxidation products malondialdehyde (MDA),the total antioxidant capacity (T-AOC) and the activity of Na⁺,K⁺-ATPase and Ca²⁺-ATPase in the brain tissue were assayed.The results showed that as compared to the model group,administration of imperatorin significantly increased the latency and decreased the number of errors within 5 min in the stepdown test.Furthermore,imperatorin treatment also significantly decreased the level of ROS and MDA,and enhanced T-AOC and the activity of Na⁺,K⁺-ATPase and Ca²⁺-ATPase in the brain tissue.These results suggested that imperatorin can significantly ameliorate the learning and memory impairment and the mechanism may be partly related to inhibiting oxidative stress in Aβ_1-42-induced model of dementia in mice.

Key words: imperatorin, A&beta, _1-42, Alzheimer&rsquo, s disease, learning and memory, step-down test, oxidative stress