Objective: The purpose of this investigation was to assess the influence of Viola odoratas hydroalcoholic extract on cognitive performance alongside changes in antioxidant activity and inflammation in rats experiencing unavoidable stressors.
Materials and methods: Forty male Wistar rats were divided into five groups: control, stress, stress+V. odorata extract, normal saline, and V. odorata. The stress and stress+V. odorata groups underwent four hours of daily restraint stress for 21 days. The extract-treated groups received V. odorata via gavage 30 min before stress. Barnes maze, elevated plus maze (EPM), hematoxylin-eosin staining, and ELISA kit were employed to evaluate memory, anxiety-like behaviors, neuronal density, and inflammatory and antioxidant factors evaluation, respectively.
Results: Administration of V. odorata extract to stressed rats significantly improved memory and recall performance (evidenced by reduced distance traveled and fewer errors in the Barnes maze test) and decreased anxiety-like behaviors (in the EPM test) compared to the stress animal. Furthermore, chronic stress caused significant increases in oxidative markers (Malondialdehyde; MDA), pro-inflammatory cytokines (Tumor Necrosis Factor-alpha; TNF-α and Interleukin-1β ), and decreased antioxidant enzyme (Gamma-glutamyl transferase; GGT) levels in rats compared to the control. Notably, the V. odorata treatment showed neuroprotective effects against stress-induced damage by enhancing antioxidant activity and increasing neuronal density in brain regions including the amygdala, hippocampus, and prefrontal cortex compared to the stressed animal.
Conclusion: Evidence from this study suggests that V. odorata may help mitigate the negative effects of stress on cognitive performance, anxiety-like behaviors, and neuronal damage. The antioxidant and anti-inflammatory characteristics of the extract probably mediate these protective effects.