Exploring Green-Synthesized Silver Nanoparticles in Neurodegeneration: a Systematic Review of Cholinesterase Enzyme Interactions.

Neurodegenerative disorders, particularly Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), represent a significant and growing global health concern in recent decades due to their complex pathology and lack of curative treatments. The fundamental cause of the evolution of these disorders is the dysfunction of cholinergic neurotransmission; those are mostly regulated by cholinesterase enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Conventional synthetic cholinesterase inhibitors like donepezil, rivastigmine, and galantamine are proposed for symptomatic relief but are often associated with adverse effects, limited bioavailability, and decreased long-term efficacy. Here, green-synthesized silver nanoparticles (AgNPs), which are derived from plant extracts and other biological systems, give an extraordinary alternative. These nanoparticles offer a biocompatible, eco-friendly, and cost-effective alternative to conventional synthetic methods. Greener AgNPs inhibit them by binding to the enzymes AChE and BChE and prevents them from breaking down neurotransmitters ACh and BCh. As a result, the count of neurotransmitters remains high in the synapse and can provide an effective synaptic transmission. Green-synthesized AgNPs can provide targeted drug delivery, enhance solubility, enhance bioavailability, improve absorption, and also be able to overcome the blood-brain barrier (BBB); all these characteristics give better therapeutic action than all conventional methods. This study evaluates the efficacy of green-synthesized silver nanoparticles in combination with several medicinal plants for treating neurodegenerative diseases, encouraging further research to upgrade these formulations for improved patient outcomes and increased clinical applicability.