Schinus terebinthifolia Raddi. Leaf Lectin (SteLL) Demonstrates Anxiolytic and Antidepressant Effects Under Monoaminergic Deficiency Induced by Reserpine

<i>Schinus terebinthifolia</i> Raddi. leaf lectin (SteLL) has been investigated for its neuromodulatory effects. Given the etiological diversity of depression, this study evaluated the effects of SteLL in a pharmacological model induced by reserpine. Mice were administered reserpine intraperitoneally for 10 days to induce anxiety- and depression-like symptoms. Before reserpine administration, animals also received SteLL (2 or 4 mg/kg, i.p.) or fluoxetine (10 mg/kg, i.p.) for 10 days. Behavioral assessments included the open field test, elevated plus maze, and tail suspension test. Body weight variation and brain levels of cytokines, noradrenaline, dopamine, and serotonin were also analyzed. In reserpine-treated mice, SteLL administration (2 and 4 mg/kg) produced anxiolytic-like effects in the open field (reduced number of rearings) and elevated plus maze (increased time spent in open arms) and significantly reduced immobility time in the tail suspension test. Additionally, SteLL prevented the body weight loss typically induced by reserpine. SteLL treatment modulated neuroinflammation by reducing IL-2 and increasing IL-10 levels in the brain. SteLL treatment restored dopaminergic and noradrenergic levels, with no effect on serotonin. In conclusion, SteLL was effective in reserpine-induced monoaminergic depletion, reversing behavioral and biochemical alterations characteristic of depression, likely through dopaminergic, noradrenergic, and anti-inflammatory mechanisms.