Phytochemicals as Protective Agents for Brain Aging

Aging is the major danger agent for many age-related disorders, including neurological diseases. Knowing the biological mechanisms of aging is critical to achieve brain health. In this regard, brain aging is characterized by neurophysiological functions gradually decline, impaired adaptive neuroplasticity, dysregulation of neuronal calcium homeostasis, neuroinflammation, and oxidatively modified molecules and organelles. Several molecular and cellular indicators of brain aging include mitochondrial dysfunction, accumulation of oxidatively damaged molecules, impaired lysosome and proteasome function, dysregulation of neuronal calcium homeostasis, inflammation, and impaired neurogenesis. Thus, therapeutic approaches target the beneficial effects of phytochemicals on aging-associated impairment of brain function. In cellular models of neurological diseases, phytochemicals, or food’s second metabolites, preserve neuronal cells against cell death, and the neuroprotective effect is attributed to antioxidant, antiinflammatory, and antiaging properties. Phytochemicals activate the neuronal antioxidant defense and survival. Mechanisms associated with neuroprotective effects of phytochemicals on the brain such as cellular defense against oxidative stress (the Nrf2-ARE antioxidant system), cell survival system (the TrkB signaling pathway), and crosstalk between TrkB signaling pathway and Nrf2-ARE antioxidant system were outlined. The recent evidence in this chapter describes the hallmarks of brain aging which affect impairment in brain function, acknowledgment of antiaging, antioxidant, and antiinflammatory effects of phytochemicals against oxidative stress and emphasizes their importance as a protective agent for brain aging and neurodegenerative disease resistance.