Cerebral edema consists in a serious deterioration of the central nervous system due to the excessive accumulation of intracellular and extracellular fluids at the cerebral level. Cerebral edema is an important cause of intracranial hypertension. In 2012 , a scientific study highlighted potential beneficial aspects of onion consumption in the treatment of this disease:
The aim of this study was to examine the potential beneficial effects of onion extract on edema induced by cerebral ischemia and on blood-brain barrier (BBB) dysfunction. The possible underlying mechanisms are investigated, in particular those related to the antioxidant effects of onion extract. Methods:
Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 2 hours followed by reperfusion in mice. Mice were treated intravenously with onion extract 30 minutes prior to the MCAO. Cerebral edema and BBB hyperpermeability were assessed by measuring brain water content and Evans blue extravasation, respectively. The breakdown of tight junction proteins was examined by immunohistochemical staining. The level of malondialdehyde was determined using the thiobarbituric acid method. The activities of glutathione peroxidase and catalase were determined by spectrophotometric assay. Results:
The researchers found that the cerebral water content in the ischemic hemisphere was significantly reduced by the onion extract treatment. The onion extract also had a significant effect on both the decrease of Evans’ blue extravasation and the inhibition of zonula occludens-1 and destruction of occludin caused by cerebral ischemia. Furthermore, the onion extract significantly prevented the brain ischemia-induced reduction of catalase and glutathione peroxidase activities and the increase in the level of malondialdehyde in brain tissue. Conclusion:
The results of this study demonstrate that onion extract prevents brain edema, BBB hyper-permeability and breakdown of tight-junction proteins, possibly through its antioxidant effects in the mouse MCAO model. This study suggests that onion extract may be a beneficial nutrient for the prevention of BBB function during cerebral ischemia. Source: https://pubmed.ncbi.nlm.nih.gov/22771051.