Neuroprotective Effect of Compounds Isolated from Euonymus alatus on Glutamate‑Induced Oxidative Stress in HT22 Hippocampal Cells

Objectives: In this study, we isolated 10 compounds from E. alatus and confirmed that compounds whether protected neuroral cell (HT22) against glutamate induced toxicity. Materials and Methods: The n‑hexane fraction of E. alatus was significantly protected HT22 cells injured by the excitotoxic amino acid, L‑glutamate. We isolated ten compounds from n‑hexane fraction of E. alatus, and they were identified as moretenone (1), moretenol (2), friedelanol (3), lupenone (4), β‑sitosterol (5), betulin (6), undecanoic acid, 1,2‑phenylene ester (7), glycerol 1‑tetracosanoate (8), methyl hydrogen tetradecanedioate (9), and 10,13‑nonadecadienoic acid, methyl ester (10) by spectroscopic data such as UV, IR, NMR, Mass spectroscopy. Results: Their neuroprotective activity was evaluated by 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide assay. Betulin (6) and methyl hydrogen tetradecanedioate (9) had significant neuroprotective activity against glutamate‑injured HT22 cells. Furthermore, reactive oxygen species level and intracellular Ca2+ was decresed by betulin (6) and methyl hydrogen tetradecanedioate (9) and these compounds increased mitochondrial membrane potential, total glutathione (GSH) level, GSH reductase activity and GSH peroxidase activity. Conclusion: Our results suggest that betulin (6) and methyl hydrogen tetradecanedioate (9) significantly protect HT22 cells against glutamate‑induced oxidative stress, through anti‑oxidative activities.