Arecoline Alleviates Depression via Gut–Brain Axis Modulation, Neurotransmitter Balance, Neuroplasticity Enhancement, and Inflammation Reduction in CUMS Mice

This study evaluated the antidepressant effects of arecoline, a bioactive alkaloid derived from areca nuts, using a mouse model of depression induced by chronic unpredictable mild stress. Arecoline treatment significantly alleviated depression-like behaviors, including anxiety, anhedonia, and despair, as evidenced by behavioral tests. Mechanistically, arecoline restored serotonin and norepinephrine levels in the brain and serum, reduced pro-inflammatory markers such as IL-1β and LPS in both serum and colon, and enhanced hippocampal neuroplasticity through increased BDNF and PSD-95 expression. Moreover, arecoline modulated gut microbiota composition, particularly enriching beneficial species like <i>Bifidobacterium pseudolongum</i> and <i>Ligilactobacillus murinus</i>, and regulated serum metabolites associated with tryptophan metabolism, neurotransmitter synthesis, and oxidative stress. These findings demonstrate that arecoline exerts its antidepressant effects via a multitargeted approach involving the gut-brain axis, neurotransmitter modulation, and neuroplasticity enhancement. This study highlights arecoline as a promising therapeutic candidate for depression, emphasizing its potential to address both central and peripheral mechanisms.