Antidepressant-like effect of Albizia zygia root extract in murine models

Background Albizia zygia (DC.) J.F. Macbr. (Leguminosae) has been used to treat mental disorders in traditional African medicine. Nonetheless, there is limited scientific evidence to justify its present use. The aim of this study was to evaluate the antidepressant activity of the hydroethanolic extract of A. zygia roots (AZE) in murine models. Methods AZE was evaluated in the tail suspension test, forced swim test, and the repeated open-space swim test of depression. In order to elucidate the mechanisms of action, the activity of AZE was re-evaluated after treating mice with selective inhibitors of monoamine biosynthesis. The potential of AZE to influence spontaneous locomotion was also examined. Results AZE (100-1000 mg/kg, p.o.) reduced the immobility time of mice in the tail suspension and forced swim tests (at least p < 0.05). In the repeated open-space swim test, AZE reduced the immobility time (at least p < 0.05) while concomitantly increasing the distance swam by mice (p < 0.01). However, the antidepressant-like activity of AZE was attenuated by α-methyl-para-tyrosine and reserpine (p < 0.0001) but not para-chlorophenylalanine. Conclusions The results of this study indicate that AZE possesses antidepressant-like properties and support the traditional use of AZE for the treatment of depression.