Effect of Aloe vera on brain indoleamine 2, 3 dioxygenase activity and tissue antioxidant status in rats subjected to swim stress

Aloe vera (AV), is a succulent plant with numerous health benefits, including antioxidant, immune-boosting, and antidepressant properties. Increased brain indoleamine 2, 3-dioxygenase (IDO) activity due to proinflammatory cytokines contributes to serotonin reduction and depression. This study investigates how AV affects brain IDO activity and liver antioxidant status in rats subjected to a forced swim test (FST). Albino Wistar rats were assigned to control and AV-treated groups (n=12/group). The test group received an aqueous extract of AV orally at 0.2g/ml/kg, while the control group received tap water for fourteen days. Behavioral analysis showed AV's anxiolytic properties in mice subjected to an elevated plus maze (EPM) test, with a significant reduction in total locomotor activity and exploratory behavior in an open field test. An antidepressant effect was indicated by decreased (p<0.05) immobility time in FST and decreased brain IDO activity in AV-treated rats. Moreover, the significant antioxidant activity of AV was reflected in elevated catalase and reduced glutathione (GSH) levels, along with considerable depletion in malondialdehyde (MDA) levels when compared to unstressed controls. Together, these findings suggest AV possesses potent antioxidant and anxiolytic properties, mitigating stress-induced depressive states by decreasing brain IDO activity, thereby increasing tryptophan availability for central serotonin synthesis.