Flavonoids and Alzheimer's disease: reviewing the evidence for neuroprotective potential

Neurodegeneration, which manifests as several chronic and incurable diseases, is an age-related condition that affects the central nervous system (CNS) and poses a significant threat to the public's health for the elderly. Recent decades have experienced an alarming increase in the incidence of neurodegenerative disorders (NDDs), a severe public health issue due to the ongoing development of people living in modern civilizations. Alzheimer's disease (AD) is a leading trigger of age-related dementia. Currently, there are no efficient therapeutics to delay, stop, or reverse the disease's course development. Several studies found that dietary bioactive phytochemicals, primarily flavonoids, influence the pathophysiological processes underlying AD. Flavonoids work well as a supplement to manufactured therapies for NDDs. Flavonoids are effective in complementing synthetic approaches to treat NDDs. They are biologically active phytochemicals with promising pharmacological activities, for instance, antiviral, anti-allergic, antiplatelet, anti-inflammatory, antitumor, anti-apoptotic, and antioxidant effects. The production of nitric oxide (NO), tumor necrosis factor (TNF-α), and oxidative stress (OS) are downregulated by flavonoids, which slow the course of AD. Hence, this research turned from preclinical evidence to feasible clinical applications to develop newer therapeutics, focusing on the therapeutic potential of flavonoids against AD.