Antidepressant effect of buddleja cordata methanolic extract in chronic stress mouse model

Background: Preclinical studies in animal models have shown anti-inflammatory, analgesic, antioxidant, and neuroprotective effects of B. cordata. Objectives: To explore the antidepressant effect of a methanolic extract of Buddleja cordata leaves (MEBc) in early maternal separation and chronic restraint stress mouse model. Materials and Methods: From day 2 to day 21, the litters were removed from the maternal cage for 3h/day. Based on the pharmacological treatments, four experimental groups were established: sham animals without maternal separation, chronic restrained stress and oral administration (S group) or 10 ml/Kg/day saline solution (SS group) or 100 mg/kg/day of MEBc (MEBc group) or 20 mg/kg/day of fluoxetine (F group). After 4 weeks of these treatments the antidepressant activity was evaluated through behavioral tests and also IL-6 determinations were performed. Results: Mice administered with MEBc showed significantly diminished immobility time in the forced swimming test (P < 0.01), tail suspension test (P < 0.001) and the time spent in the open arm of the elevated plus-maze (P < 0.01) versus SS group. By contrast, animals treated with fluoxetine only diminished immobility time in the tail suspension test (P < 0.01). The vegetal extract was more effective (P < 0.05) that fluoxetine in preventing the increase of interleukin 6 (IL-6) over the hippocampus and prefrontal cortex region (45 and 20 %, respectively). Conclusion: These results demonstrate the antidepressant and anxiolytic effects of MEBc over the chronic stress depression-induced model.