The investigation of antidepressant and anxiolytic effects of Euterpe oleracea and its mechanisms of action in rats

Euterpe oleracea (EO) contains a wide variety of polyphenolic compounds, including phenolics, flavonoids, and anthocyanins, which exhibit strong antioxidant properties. EO has been proposed to alleviate oxidative stress and inflammation in brain cells. Since exposure to extreme environmental stressors-such as natural disasters, infectious disease outbreaks, and mass trauma- can trigger anxiety, depression, and cognitive decline, this study aimed to investigate the potential antidepressant and anxiolytic effects of EO. Sixty-four male Wistar albino rats (300–350 g) were randomly divided into eight groups: control, EO (30, 100, and 300 mg/kg), amitriptyline (20 mg/kg), fluoxetine (20 mg/kg), diazepam (5 mg/kg), and ketamine (5 mg/kg). All treatments were administered orally, and behavioral tests were conducted 1.5 hours after drug administration. Antidepressant-like activity was evaluated using the forced swimming test (FST), while anxiolytic-like effects were assessed through the elevated plus maze (EPM). Locomotor activity was also measured using an activity meter to rule out nonspecific motor effects. Statistical analysis was performed using the Kruskal–Wallis test, and p < 0.05 was considered statistically significant. All EO doses significantly reduced immobility time in the FST and time spent in closed arms in the EPM compared to the control group. The 100 mg/kg EO group showed effects similar and comparable to those of amitriptyline, ketamine, and diazepam. In contrast, fluoxetine showed no significant effects, possibly due to the limitations of acute administration. These findings suggest that EO, particularly at 100 mg/kg, may possess antidepressant and anxiolytic properties similar to standard pharmacological agents.