The Blood–brain barrier (BBB), which is made up primarily of brain microvascular endothelial cells and astrocytes linked by tight junctions (TJs) and adhesion molecules (AMs), keeps the brain parenchyma and extracellular fluid in a homeostatic balance. BBB disruption is a prevalent hallmark of neurodegenerative illnesses such as stroke, traumatic brain injury, and Alzheimer's disease, according to mounting data. Reactive oxygen species (ROS) are recognised to play a significant role in generating BBB disruption via TJ alteration, AM induction, cytoskeletal remodelling, and matrix metalloproteinase activation, among other pathological routes of BBB dysfunction. As a result, antioxidants may have a positive effect on BBB dysfunction-related brain illnesses. The origins of ROS production in different cells that make up or surround the BBB, such as BBB endothelial cells, astrocytes, microglia, and neutrophils, were covered in this review. We also looked at the numerous pathogenic pathways that ROS in these cells use to damage the BBB. Finally, we summarised the effects of several natural polyphenols on BBB dysfunction in order to propose a therapeutic strategy for brain illnesses caused by BBB disruption.
