Curcumin reprograms metabolic pathways and MAPK signaling to exert antidepressant effects.

Background: Depression is a prevalent and debilitating mental disorder with limited treatment options. Curcumin, a natural compound with neuroprotective and anti-inflammatory properties, has shown potential antidepressant effects, though the underlying mechanisms remain incompletely understood. Methods and results: In this study, we investigated the therapeutic effects and molecular mechanisms of curcumin in a chronic unpredictable mild stress (CUMS)-induced rat model of depression. Behavioral assessments, including the sucrose preference test, forced swim test, and open field test, demonstrated that curcumin (50 and 100 mg/kg, orally administered for 21 days) alleviated CUMS-induced anhedonia, behavioral despair, and anxiety-like behaviors, in a dose-dependent manner, with the 100 mg/kg dose exhibiting superior efficacy. Metabolomic profiling of the prefrontal cortex revealed significant metabolic disturbances in CUMS rats, particularly in starch and sucrose metabolism, which were progressively restored by curcumin. Functional enrichment analysis highlighted modulation of neuroinflammation, bioenergetic homeostasis, and signal transduction pathways as key biological processes associated with curcumin's effects. Integrated multi-omics and machine learning approaches identified the MAPK signaling pathway as a central regulatory node. qPCR validation confirmed that curcumin normalized the expression of key MAPK-related genes, including BDNF, EGFR, ERK2, JUN, RAF1, and TNF, with high-dose curcumin consistently showing the most pronounced therapeutic effects. Conclusion: Our findings demonstrate that curcumin exerts potent antidepressant effects through multi-target mechanisms involving metabolic reprogramming and coordinated regulation of the MAPK signaling pathway. This study provides novel mechanistic insights into curcumin's polypharmacological actions, supporting its potential as a multi-modal therapeutic agent for depression by simultaneously modulating neurotrophic support, inflammatory responses, and intracellular signaling cascades.