Benzimidazole-based Multi-target Directed Ligands: A Comprehensive Review of Therapeutic Potential in Alzheimer's disease.

Alzheimer's Disease (AD) is a multifactorial neurodegenerative disorder characterized by progressive cognitive decline. Current treatments provide only symptomatic relief and fail to halt disease progression, underscoring the urgent need for disease-modifying interventions. The complex interplay among amyloid-β aggregation, tau hyperphosphorylation, cholinergic dysfunction, oxidative stress, metal dyshomeostasis, and neuroinflammation necessitates multi-target therapeutic strategies. Benzimidazole analogues have emerged as a promising scaffold in this context, owing to their structural flexibility, broad pharmacological activity, and demonstrated multi-target capability. This review critically analyses recent developments in the design, synthesis, and biological evaluation of benzimidazole-based compounds as potential anti-Alzheimer's agents. Particular emphasis is placed on structure-activity relationships governing interactions with key AD-relevant targets, including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), β-secretase (BACE1), tau-related protein kinases, and metal chelation relevant to amyloid pathology. The neuroprotective, antioxidant, and anti-inflammatory properties of these derivatives are also discussed in the context of their potential disease-modifying relevance. The advantages of benzimidazole-based Multi-target Directed Ligands (MTDLs) over conventional single-target approaches are highlighted, particularly their capacity to address multiple pathological hallmarks of AD simultaneously. Key limitations, including pharmacokinetic challenges and the absence of clinical validation, are critically evaluated to provide a balanced perspective. Overall, this review establishes benzimidazole analogues as promising lead structures in AD drug discovery and aims to guide future medicinal chemistry efforts toward more effective, disease-modifying therapies.