FMN reduces hippocampal neuronal damage and oxidative stress in rats, improves depression-like behavior in rats with mild stress (CUMS)-induced depression, and reverses the CUMS-induced decrease in nuclear factor erythroid-2-related factor 2 (Nrf2) protein and increase in NQO⁃1 and HO⁃1 proteins in the nucleus (Yao et al., 2022). Here, NFE2L2 is linked to major depressive disorder.