Protective effect of morin hydrate against chronic unpredictable mild stress-induced depression in mice

Abstract

Morin flavonoid has been reported to possess anti-stress, anti-anxiety, nootropic, anti-oxidant, and neuroprotective properties. In the present study, morin hydrate was evaluated for antidepressant-like activity in unstressed and stressed Swiss young male albino mice. The mice were subjected to chronic unpredictable mild stress (CUMS) for 21 successive days. Morin hydrate (10, 20, and 40 mg/kg, p.o.) and fluoxetine (20 mg/kg, p.o.) per se were administered for 21 successive days to separate groups of unstressed and stressed mice. Tail suspension test (TST) and sucrose preference test were used to evaluate the effect of Morin on depression-like behavior in mice. During the study, the effect of Morin on lipid peroxidation, reduced glutathione, catalase, nitrite, corticosterone, and MAO-A activity was estimated. All the results were analyzed by analysis of variance (ANOVA) followed by the Tukey–Kramer multiple comparison test using Graph Pad Instat (GPIS) package, version 3.05. Morin (20 and 40 mg/kg, p.o.) per se administered for 21 successive days significantly decreased the immobility period of stressed mice in the tail suspension test as compared to vehicle-treated stressed mice, indicating significant antidepressant-like activity. Morin significantly restored the reduced sucrose preference (%) in stressed mice as compared to vehicle-treated stressed mice. Further, morin significantly reversed the stress-induced increase in brain thiobarbituric acid-reactive substances (TBARS), plasma nitrite, and corticosterone levels, and increased the stress-induced decrease in brain catalase levels. The highest dose (40 mg/kg) of morin hydrate significantly inhibited brain MAO-A activity in stressed mice. Thus, morin hydrate showed significant antidepressant-like activity in mice subjected to CUMS, probably through inhibition of brain MAO-A activity, decrease in plasma nitrite and corticosterone levels, and due to its antioxidant activity.