Neuroprotective and Antidepressant-like Effects of Gladiolus aequinoctialis (Irideaceae) Ethanolic Extract in Wistar Rats

Abstract

Aims: Depression causes wide changes in the brain and blood parameters. This study investigated the effect of the ethanol extract of Gladiolus aequinoctialis (G. aequinoctialis) in regulation of hormones and neurotransmiiters balance in depressed Wistar rats. Methodology: Depression was evaluated using sucrose and force swim tests. None depressed adult Wistar rats were depressed using CUMS (deprivation of water, food, dark cycle and congested) for over 6 weeks. They were grouped into group of 5 rats and treated with extract at different doses (25, 50, 100 mg/kg), 5 ml/kg of distilled water (Negative control) and 1 mg/kg of diazepam (positive control) for 38 days. After treatment, the motor activities were evaluated and animals were sacrificed. Brain tissue was examined through histological examination as well as brain levels of dopamine (DA), norepinephrine (NE) and serotonin (5-HT), and serum levels of, ACTH (adrenocorticotropic hormone), CRH (cortocotropin releasing hormone) and CORT (corticosterone) were evaluated using ELISA kits. The analysis of variance (ANOVA) followed by the Student-Newman-Keuls test was performed to establish the difference between groups at p<0.05. Results: Results indicated that the extract of G. aequinoctialis caused a significant increase in sucrose intake and reduction in immobility time in swimming test, motor coordination, locomotive behavior compared to the negative control (p<0.05). Extract also reduced the brain levels of DA, NE and 5-HT in depressed animals compared to non-treated. Moreover, extract significantly (p<0.05) lowered serum levels of ACTH, CRH and CORT in depressed animals. Furthermore, the extract prevented the neuropathological alteration in the hippocampus, amygdala, gyrus and cortex compared to depressed animals. Conclusion: This study therefore demonstrated that the consumption of the ethanolic fraction of G. aequinoctialis by preventing the disruption of motor activities, changes in levels of DA, NE, 5-HT ACTH, CRH and CORT in depressed rats, demonstrated it is a promising phytomedecine for the management of depression.