ISSN 2348-313X (Print) International Journal of Life Sciences Research ISSN 2348-3148 (online) Vol. 8, Issue 1, pp: (41-51), Month: January - March 2020, Available at: www.researchpublish.com
Behavioral and Biochemical Evidences of Antidepressant Activity of Ethanolic Extract of Morus Mesozygia Leaves in Mice Subjected to Chronic Unpredictable Mild Stress Adegbuyi O. Aderibigbe1, Abimbola A. Sowunmi1, Yusuf Usman1, Elizabeth Olonode2 1
Deparment of Pharmacology & Therapeutics,University of Ibadan, Ibadan, Nigeria 2
Deparment of Pharmacology, Afe Babalola University, Ado-Ekiti, Nigeria
Corresponding Author: Abimbola A. Sowunmi, sowunmiabimbola2@gmail.com
Abstract: Members of the plant genus Morus are widely used traditionally in Asia to treat depression, Morus mesozygia is the only member of the genus native to Africa. The study was carried out to evaluate the antidepressant-like activity of Ethanolic Extract of Morus Mesozygia Leaves (EEMM) in mice subjected to chronic unpredictable mild stress (CUMS). Materials and Methods: Male Swiss mice were randomly assigned to 6 different experimental groups and treated groups were given EEMM (2.5, 5 or 10 mg/kg, i.p) 30 minutes before exposure to different mild stressors in the CUMS paradigm for 14 days. They were then subjected to Sucrose Preference Test (SPT) and Forced Swim Test (FST). At the end of the behavioral studies, the levels of Nitrite, Malondialdehyde and Gluthathione in the homogenate of the brain tissues were determined spectrophotometrically. One-way ANOVA was used to statistically determine significant differences. Result: The results showed that EEMM at all doses significantly decreased immobility periods of stressed mice in the forced swim test without increasing the locomotor activity in open field test, and as well reversed the stress-induced anhedonia in the sucrose preference test. Biochemical analysis showed that EEMM significantly (p < 0.05) reduced the concentrations of Nitrite and MDA while the GSH level was elevated in the brains of mice exposed to CUMS. Conclusion: The findings provide significant evidences that EEMM has valid antidepressant-like activity, and might be useful in the management of stress-related disorders on account of its adaptogenic and neuroprotective effects as it prevents oxidative damage in brain tissues. Keywords: Anhedonia, Stress, Neuroprotective, Depression, Medicinal plant.
1. INTRODUCTION Depression is a debilitating and life-threatening illness that negatively affects thoughts, behavior, feelings and sense of well-being. Depression usually presents as a triad of symptoms characterized by low or decreased mood, anhedonia and low energy or fatigue [27]. Depression can occur at any age from childhood to late life, oftentimes, if left untreated may result in fatal outcome with suicide as the hallmark ending [39]. The global prevalence of the disease is very high, reaching about 21% of the population [35]. In most cases, depression present as a complex heterogeneous disorder of diverse variants having more than one etiology, but more commonly, stressful life events have been identified as the major factor that precipitates most depressive episodes [36]. Studies combining behavioral, molecular and electrophysiological techniques reveal that major aspects of depression results from maladaptive stress-induced neuroplastic changes in the neural circuits and these neuroplastic alterations are reversible upon administration of antidepressants [11]. An identified mechanism is the stress-induced structural alteration resulting from excessive reactive oxygen species production causing oxidative damage to macromolecules including lipids, proteins and DNA, leading to neuronal dysfunction such as decrease release of the monoamine neurotransmitter, hence, the monoamine theory of
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