Neuroprotective responses of quercetin in regulation of biochemical, structural, and neurobehavioral effects in 28-day oral exposure of iron in rats.

BACKGROUND: Iron is one of the essential metals that functions as a cofactor in various biological cascades in the brain. However, excessive iron accumulation in the brain may lead to neurodegeneration and may show toxic effects. Quercetin, a pigment flavonoid compound, has been proven to be a potent antioxidant and anti-inflammatory that can inhibit lipid peroxidation during metal-induced neurotoxicity. Although iron-induced neuroinflammation and neurodegeneration have been reported in many studies, but the proof for its exact mechanisms needs to be explored. PURPOSE: The key target of the study was to explore the neuroprotective effect of quercetin after oral exposure of iron in rats and explore its underlying molecular mechanisms. RESULTS: The outcomes of the study have shown that oral exposure to ferrous sulfate may modulate behavioral paradigms such as locomotor activity, neuromuscular coordination, and increased anxiety level. The pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6), apoptotic protein (caspase 3), beta-amyloid and phosphorylated tau were found to be increased on iron exposure. Also, the expressions of ferritin heavy and light chain, BACE-1 and GFAP expressions were altered. These behavioral, structural, and biochemical alterations in the brain were significantly and dose-dependently reversed by treatment with quercetin. CONCLUSION: The current study provides a fundamental understanding of molecular signaling pathways, and structural proteins implicated in iron-induced neurotoxicity along with the ameliorative effects of quercetin.

Pharmacological and Pathological Relevance of S100 Proteins in Neurological Disorders.

The S100 protein is one of the calcium-binding proteins associated with Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. S100 proteins are expressed in the central nervous system by oligodendrocytes, astrocytes and neurons during both normal and disease conditions. Although amyloid-beta aggregation and hyperphosphorylated tau plaques are the main pathological hallmarks of Alzheimer's disease, the S100 protein family is closely associated with neuroinflammation in several neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis in addition to various types of cancer and other brain diseases. This review aims to present the key role of S100 proteins and their different relevant isoforms, along with the various approaches used for the regulation of these proteins in several neurodegenerative disorders.