Exploring the Potential of Herbal Compounds as Autophagy Modulators in Alzheimer's Disease: A Comprehensive Review

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that causes atrophy of brain cells, leading to their death, and has become a leading cause of death in aging populations worldwide. AD is characterized by β-amyloid (Aβ) deposition and tau phosphorylation in neural tissues, but the precise pathophysiology of the disease is still obscure. Autophagy is an evolutionarily targeted mechanism that is necessary for the elimination of neuronal and glial misfolded proteins as well as proteins. It also plays an essential role in synaptic plasticity. The aberrant autophagy primarily influences the process of aging and neurodegeneration. Autophagy significantly influences how Aβ and tau function physiologically, therefore, atypical autophagy is expected to perform an important role in Aβ deposition and tau phosphorylation characteristic in the development of AD. Bioactive phytoconstituents could majorly contribute as a natural yet effective alternative approach to slow down the progression of neurodegeneration and promote the active aging process in elderly patients. Over the recent years, it is well evidenced that different secondary metabolites including polyphenols, alkaloids, terpenes, and phenols exhibited neuroprotective effects, and attenuated brain damage, and cognitive impairment in vitro as well as in vivo. Additionally, the underlying mechanism of action shared by them is the regulation of competent autophagy via the removal of aggregated protein and mitochondrial dysfunction. The present article is structured as a reference for researchers keen to investigate and assess the new natural compound-mediated therapeutic approach for AD treatment through the modulation of autophagy.