Interplay of gut microbiota and oxidative stress: Perspective on neurodegeneration and neuroprotection

BACKGROUND: Recent research on the implications of gut microbiota on brain functions has helped to gather important information on the relationship between them. Pathogenesis of neurological disorders is found to be associated with dysregulation of gut-brain axis. Some gut bacteria metabolites are found to be directly associated with the increase in reactive oxygen species levels, one of the most important risk factors of neurodegeneration. Besides their morbid association, gut bacteria metabolites are also found to play a significant role in reducing the onset of these life-threatening brain disorders. AIM OF REVIEW: Studies done in the recent past raises two most important link between gut microbiota and the brain: “gut microbiota-oxidative stress-neurodegeneration” and gut microbiota-antioxidant-neuroprotection. This review aims to gives a deep insight to our readers, of the collective studies done, focusing on the gut microbiota mediated oxidative stress involved in neurodegeneration along with a focus on those studies showing the involvement of gut microbiota and their metabolites in neuroprotection. KEY SCIENTIFIC CONCEPTS OF REVIEW: This review is focused on three main key concepts. Firstly, the mounting evidences from clinical and preclinical arenas shows the influence of gut microbiota mediated oxidative stress resulting in dysfunctional neurological processes. Therefore, we describe the potential role of gut microbiota influencing the vulnerability of brain to oxidative stress, and a budding causative in Alzheimer's and Parkinson’s disease. Secondly, contributing roles of gut microbiota has been observed in attenuating oxidative stress and inflammation via its own metabolites or by producing secondary metabolites and, also modulation in gut microbiota population with antioxidative and anti-inflammatory probiotics have shown promising neuro resilience. Thirdly, high throughput in silico tools and databases also gives a correlation of gut microbiome, their metabolites and brain health, thus providing fascinating perspective and promising new avenues for therapeutic options.