Effects of potassium bromate on Rattus norvegicus brain antioxidant markers, acetylcholinesterase activity, and DNA fragmentation: investigation of therapeutic effect of Allium cepa

Background Allium cepa is well-known for its antioxidant capabilities and contains potent antioxidant quercetin (3, 30, 4, 5, 7-pentahydroxyflavone). We investigated the therapeutic effects of aqueous extract of Allium cepa (AEAC) that is quercetin-rich against potassium bromate (KBrO3)-induced oxidative damage in the brains of male Wistar rats using biochemical, immunohistochemical, and histological markers. For 90 days, 40 male Wistar rats were administered KBrO3, KBrO3 + AEAC, and/or quercetin on alternate days, or AEAC and quercetin alone. Results KBrO3 significantly (p > 0.05) suppressed and diminished antioxidant enzymes and acetylcholinesterase activities with notable decreased total protein levels. Additionally, oxidative stress biomarkers (MDA and NO), as well as DNA fragmentation, all increased significantly (p > 0.05). The immunohistochemical expression of P53, caspase 3, and COX2 protein also increased significantly in the cerebral cortex of the KBrO3-treated groups, but BCL-2 protein expression decreased significantly. Histological examination of brain tissues revealed patterns that corresponded to the enzyme markers. The effects of KBrO3 were all attenuated by the administration of AEAC and quercetin. Conclusions This research demonstrates the therapeutic effects of Allium cepa on KBrO3-induced oxidative stress, and biochemical perturbation in the brain of Rattus norvegicus . Even though the exact mechanism of action of Allium cepa at the molecular level cannot be completely deduced from the results presented above, it could possibly be due to a combination of its antioxidant, anti-inflammatory, and apoptotic mechanisms. Further studies are required to examine the molecular pathways responsible for these aforementioned therapeutic effects.