Antidepressant-like effects of a methanol extract of Leonotis nepetifolia in mice

Abstract

This study evaluated the antidepressant-like effects of a methanol extract of Leonotis nepetifolia in behavioural tests in mice. Our results showed that a single administration of the extract significantly reduced immobility behaviour in the tail suspension test, while a triple administration was necessary to diminish the immobility behaviour in the forced swimming test. A daily dose for 28 days of the extract improved the body weight gain and significantly reduced the corticosterone levels of mice exposed to chronic unpredictable mild stress. The extract's metabolic profile revealed the presence of nepetaefolin, methoxynepataefolin, and 7-O-β glucoside luteolin as the main products. The extract's acute and repeated administration produced antidepressant-like effects in animals subjected to chronic stress. Our results suggest the hypothalamus hypophysis adrenal participates in the extract antidepressant actions. These results show that alterations in behaviour elicited by stress can be prevented with L. nepetifolia treatment.