Phytochemicals-based Therapeutics against Alzheimer's Disease: An Update

Alzheimer's disease (AD) is one of the main healthcare challenges of the twenty-first century, not only affecting millions of people's quality of life but also increasing the burden on the medical community, families, and society. It is a neurodegenerative disorder characterized by learning and cognitive dysfunction, behavioral turbulence, and memory loss and is a major cause of dementia, contributing to 50-60 % of dementia cases in patients above the age of 65. The major pathophysiological changes include accumulation of beta-amyloid plaques (Aβ), highly phosphorylated tau protein, neuroinflammation, GABA neurotransmission disruption, mitochondrial dysfunction, neuronal damage due to free radicals, and decreased concentration of acetylcholine (ACh) and butyrylcholine (BCh). The inability of commercial therapeutics, such as donepezil, rivastigmine, galantamine, and tacrine, leads to the attraction toward phytochemical-based therapeutics. Phytochemicals derived from plants exhibit neuroprotection via targeting apoptosis, neurotrophic factor deficit, mitochondrial dysfunction, oxidative stress, and abnormal accumulation of proteins. Here, we discussed some of the neuroprotective phytochemicals used for the treatment of neurodegenerative diseases like AD and dementia.