Design, synthesis, and evaluation of febuxostat derivatives bearing 1,2,3-triazole: potent inhibitors of microglia-mediated neuroinflammation and oxidative stress via Nrf2-HO-1 activation

Major depressive disorder (MDD) represents a serious psychiatric condition with limited treatment options. Targeting microglial inflammation and the associated oxidative stress represents a promising therapeutic strategy for MDD. In this study, 33 novel febuxostat derivatives were designed and synthesized by conjugating the febuxostat core with various 1,2,3-triazole moieties via click reaction. All synthesized compounds were evaluated for their anti-inflammatory activity in LPS-stimulated BV-2 microglial cells. Among them, Compound 6i and 6j emerged as the most potent candidate, significantly suppressing NO production (IC₅₀ values of 5.90 ± 0.16 μM and 3.45 ± 0.18 μM, respectively), pro-inflammatory cytokines IL-1β, IL-6, TNF-α, and the upstream inflammatory enzymes COX-2 and iNOS expression without cytotoxicity. Mechanistic studies revealed that compounds 6i and 6j activated the Nrf2-HO-1 pathway, attenuated ROS accumulation, and restored GSH levels and SOD activity. Molecular docking further revealed that compounds 6i and 6j bind strongly to Keap1 with binding energies, suggesting that they prevent Nrf2 degradation by occupying the Keap1 binding pocket. In vivo, compound 6j ameliorated LPS-induced depressive-like behavior in mice, concomitant with reduced microglial/astrocytic activation and decreased IL-1β/TNF-α mRNA expression in the hippocampus. These findings suggest that compound 6j exerts antidepressant-like effects through Nrf2-HO-1-mediated antioxidant and anti-inflammatory mechanisms, representing a promising lead compound for MDD treatment.