COVID-19 and Its Impact on Onset and Progression of Parkinson’s and Cognitive Dysfunction

In the COVID-19 pandemic, neurological complications have emerged as a significant cause of morbidity and mortality. A wide range of neurological manifestations ranging from cognitive or memory disturbances, headache, loss of smell or taste, confusion, and disabling strokes have been reported during and post COVID conditions. The COVID-19 virus can utilize two possible pathways for invasion into the brain, either through retrograde axonal transport (olfactory route) or by crossing the blood-brain barrier (BBB). Furthermore, the production of SARS-CoV-2-associated cytokines, such as interleukin (IL)-6, IL-17, IL-1b, and tumor necrosis factor (TNF), is able to disrupt the BBB. The neuroinvasive nature of SARS-CoV-2 has a more severe impact on patients with preexisting neurological manifestations such as Parkinson’s disease (PD). Pathological features of PD include selective loss of dopaminergic neurons in the substantia nigra pars compacta and aggregation of α-syn proteins present in neurons. Interaction between SARS-COV-2 infection and α-synuclein might have long-term implications on the onset of Parkinsonism by the formation of toxic protein clumps called amyloid fibrils—a hallmark of Parkinson’s. Molecular modeling is an emerging tool to predict potential inhibitors against the enzyme α-synuclein in neurodegenerative diseases by using plant bioactive molecules