PHYTOCONSTITUENTS INFLUENCING ALZHEIMER ATHOGENESIS AND PREVENTION: A COMPREHESIVE REVIEW
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and behavioral impairment, primarily associated with amyloid-? plaque accumulation, neurofibrillary tangles, oxidative stress, neuroinflammation, and cholinergic dysfunction. Despite extensive research, currently available therapies provide only symptomatic relief and fail to halt disease progression. In recent years, increasing attention has been directed toward plant-derived phytoconstituents due to their multitargeted mechanisms, safety profile, and neuroprotective potential. This comprehensive review explores the role of major phytoconstituents influencing Alzheimer’s disease pathogenesis and prevention, including flavonoids, alkaloids, polyphenols, terpenoids, and phenolic acids. Key bioactive compounds such as curcumin, resveratrol, quercetin, kaempferol, ginkgolides, catechins, and bacosides have demonstrated significant antioxidant, antiinflammatory, anti-amyloidogenic, and acetylcholinesterase inhibitory activities in both preclinical and clinical studies. These phytochemicals modulate multiple signaling pathways involved in neuronal survival, synaptic plasticity, and mitochondrial function, thereby reducing neuronal damage and cognitive impairment. The review also highlights challenges related to bioavailability, blood–brain barrier permeability, and standardization of herbal formulations. Overall, phytoconstituents represent promising therapeutic and preventive agents against Alzheimer’s disease, warranting further clinical validation and formulation optimization for effective translational application.