Cholinesterase Inhibitors from Plants and Their Potential in Alzheimer's Treatment: Systematic Review

Introduction: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory loss and cognitive decline, primarily due to dysfunction of acetylcholine caused by acetylcholinesterase and butyrylcholinesterase. While synthetic cholinesterase inhibitors like donepezil, rivastigmine, and galantamine are commonly used, they have notable side effects, prompting interest in natural alternatives. Medicinal plants, rich in bioactive compounds like flavonoids and alkaloids, have shown potential as cholinesterase inhibitors with additional antioxidants and anti-inflammatory benefits. This study aimed to evaluate the cholinesterase-inhibiting effects of various plant species and their compounds to identify new therapeutic candidates and reduce side effects. Method: A PRISMA-compliant review was conducted, screening studies from multiple databases, with a final inclusion of 64 in vivo studies. Results: These studies highlighted plant extracts such as Ferula ammoniacum, Elaeagnus umbellata, Bacopa monnieri, and Centella asiatica, which improved memory, reduced oxidative stress, and provided neuroprotection. Some extracts also reduced amyloid plaques, enhanced neuronal integrity, and restored cholinesterase activity, indicating their potential as therapeutic agents for AD and other neurodegenerative diseases. Conclusions: The findings underscore the promise of plant-based compounds in treating cognitive decline and cholinergic dysfunction in AD, advocating for further research into their therapeutic potential.