Potential of medicinal plant compounds to targeting Tau protein in the therapy of Alzheimer’s disease– A review

Alzheimer’s disease (AD) is a devastative neurodegenerative disorder with complex etiology. AD is characterized by blood-brain barrier disruption, oxidative stress, mitochondrial impairment, neuro- inflammation, hypo-metabolism; it decreases in acetylcholine levels and a reduction of cerebral blood flow. It is also not solely the end-product of aberrantly processed, misfolded, and aggregated oligomeric amyloid- beta peptides but hyper phosphorylated Tau (tubulin binding protein) which formed senile plaque and intracellular neurofibrillary tangles respectively. However, despite the long-term and worldwide effort for a more effective therapy, the only available treatment is a symptomatic use of acetylcholinesterase inhibitors and memantine. Then, many researchers focused their attention to modulate amyloid-beta peptides. These therapeutic approaches as well as those based on cholinergic or amyloid theory have not brought the desired benefits yet. Thus, the main features related with the Tau pathology found in AD are Tau phosphorylation and aggregation. Based on the biochemically diverse range of pathological Tau protein, a number of approaches have been proposed to develop new potential therapeutics like inhibition of Tau phosphorylation, proteolysis and aggregation; promotion of intra- and extracellular Tau clearance and stabilization of microtubules (MTs). Medicinal plants have been used in different systems of medicine and exhibited their powerful roles in the management and cure of memory disorders. This review paper discusses the potential of medicinal plant molecules to targeting Tau protein in Alzheimer’s disease therapy.