Abstract
Background. The increasing prevalence of mood disorders among the elderly, together with the growing interest in medicinal plants and complementary therapies, highlights the need for further research in this field. The present study investigated the effects of the hydroalcoholic extract of Melissa officinalis on anxiety-like behavior and oxidative stress parameters in the hippocampus of aged mice.
Methods. In this study, a total of 45 male albino mice were used, including young (2 months old) and aged (24 months old) animals. The animals in the aged intervention group received Melissa officinalis extract orally at a dose of 150 mg/kg body weight per day, while the aged and young control groups received normal saline orally for 14 days. At the end of the treatment period, behavioral assessments, including the Open Field Test and the Elevated Plus Maze, were performed. In addition, serum corticosterone levels, total antioxidant capacity, and hippocampal levels of malondialdehyde, superoxide dismutase, and glutathione peroxidase were measured.
Results. Anxiety-like behavior was significantly increased in the aged control group compared with the young control group (P<0.001). This change was accompanied by elevated serum corticosterone levels, increased malondialdehyde concentrations, and reduced antioxidant enzyme activities in the hippocampus (P<0.01). Administration of the extract significantly improved anxiety-like behavior (P<0.01) and reduced serum corticosterone levels (P<0.05) in the intervention group compared with the aged control group. Moreover, treatment with the extract resulted in reduced malondialdehyde levels (P<0.01) and improved antioxidant enzyme activities (P<0.05).
Conclusion. Overall, the findings suggest that the anxiolytic effects of Melissa officinalis in aged mice are mediated, at least in part, through attenuation of stress axis activity, reduction of oxidative stress, and enhancement of hippocampal antioxidant status.
Practical Implications. The use of Melissa officinalis extract may exert anxiolytic effects in the elderly by improving hippocampal antioxidant defenses.