Glutamate-mediated oxidative stress causes neuronal cell death by increasing intracellular Ca2+ uptake, reactive oxidative species (ROS) generation, mitogen-activated protein kinase (MAPK) activation, and translocation of apoptosis-inducing factor (AIF) to the nucleus. In the current study, we demonstrated that corydaline exerts potent neuroprotective effects against glutamate-induced neurotoxicity. Treatment with 5 mmol/L glutamate increased cellular Ca2+ influx, ROS generation, MAPK activation, and AIF translocation. In contrast, corydaline treatment decreased cellular Ca2+ influx and ROS generation. Western blot analysis revealed that glutamate-mediated MAPK activation was attenuated by corydaline treatment. We further demonstrated that corydaline treatment inhibited the glutamate-mediated translocation of AIF to the nucleus. We propose that corydaline is a promising lead structure for the development of safe and effective neuroprotectants.

Introduction
Materials and Methods
    1. Cell culture
    2. Cell viability assay
    3. Measurement of ROS
    4. Measurement of cellular Ca2+ concentration
    5. Western blot analysis
    6. Statistical analysis
Results
    1. Corydaline ameliorates glutamate-induced neuronalcell death
    2. Corydaline inhibits ROS and cellular Ca2+accumulation in HT22 cells
    3. Corydaline regulates the Bcl-2 and Bax proteinlevels in HT22 cells
    4. Corydaline suppresses glutamate-induced MAPKactivation
    5. Corydaline suppresses AIF nuclear translocation
Discussion
Funding
Conflicts of Interest
Supplementary Data
References

• Baskar Selvaraj(Natural Product Research Center, Institute of Natural Product, Korea Institute of Science and Technology, Gangneung 25451, Republic of Korea, Convergence Research Center of Dementia, Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea, Division of Bio-Medical Science and Technology, University of Science and Technology, Daejun 34113, Republic of Korea)
• Dae Won Kim(Department of Biochemistry and Molecular Biology, Research Institute of Oral Science, College of Dentistry, Gangneung Wonju National University, Gangneung 25457, Republic of Korea)
• Ki-Yeon Yoo(Department of Anatomy, College of Dentistry, Gangneung Wonju National University, Gangneung 25457, Republic of Korea)
• Keunwan Park(Natural Product Informatics Research Center, Institute of Natural Product, Korea Institute of Science and Technology, Gangneung 25451, Republic of Korea)
• Thi Thu Thuy Tran(Institute of Natural Product Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam)
• Jae Wook Lee(Natural Product Research Center, Institute of Natural Product, Korea Institute of Science and Technology, Gangneung 25451, Republic of Korea, Convergence Research Center of Dementia, Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea, Division of Bio-Medical Science and Technology, University of Science and Technology, Daejun 34113, Republic of Korea) Corresponding author
• Heesu Lee(Department of Anatomy, College of Dentistry, Gangneung Wonju National University, Gangneung 25457, Republic of Korea) Corresponding author