The Aqueous Extract of Mentha piperita (Peppermint) Can Alter Depression Parameters: A Behavioral Study in Mice

Background: This study aimed to investigate the potential antidepressive-like effect of the aqueous extract of Mentha piperita (peppermint) leaves using two predictive models of depression, namely, forced swimming test (FST) and tail suspension test (TST), in male Wistar albino mice. For this purpose, after weighting, coding, and classifying the mice, they were grouped (n=۶) as test (۱۷۵ mg/kg, ۳۵۰ mg/kg, and ۷۰۰ mg/kg M. piperita aqueous extract; i.p.) and control (۲۰ mg/kg fluoxetine and ۳۰ mg/kg imipramine; i.p.) groups and the blank group (normal saline; i.p.) and received medication or extract for ۲۸ days before the tests. Results: All doses of the aqueous peppermint extract compared to the control group markedly reduced the immobility duration in both FST and TST when administered intraperitoneally for ۲۸ days. In addition, our results demonstrated that ۳۵۰ mg/kg and ۷۰۰ mg/kg of the peppermint aqueous extract increased swimming time significantly (P<۰.۰۰۱) without any significant change in climbing (struggling) duration. Conclusion: The results of this study suggest that the aqueous extract of Mentha piperita leaves has anti-depressant-like activity in the animal models of depression that might be a cause of increasing central serotonergic activity. However, more studies are required to determine the exact mechanisms of action.