Multi-Target Phytochemical Intervention in Alzheimer’s Disease Pathology: In Silico and Experimental Validation Using Nigerian Medicinal Plant Compounds

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterised by amyloid-beta plaque deposition, tau hyperphosphorylation, cholinergic neurotransmitter deficits, and neuroinflammation. Its multi-factorial pathology requires multi-target pharmacological interventions, for which phytochemical-rich Nigerian medicinal plants offer a structurally diverse yet underexplored chemical pool. This study constructs a multi-target, multi-compound therapeutic framework by integrating in silico network pharmacology, molecular dynamics simulation, and in vitro experimental validation for selected compounds from Gongronema latifolium, Morinda lucida, and Nauclea latifolia. Using validated AD target proteins (AChE, BuChE, BACE-1, GSK-3beta, NLRP3), the study performs ensemble docking, molecular dynamics simulations (100 ns), and MM-PBSA binding free energy calculations. Top computational candidates are evaluated in AChE and BuChE fluorometric assays, BACE-1 enzymatic inhibition assay, and an amyloid-beta aggregation thioflavin-T fluorescence assay. Selected candidates are evaluated for blood-brain barrier permeability using a PAMPA-BBB model. Luteolin-7-glucoside, strictosamide, and vitexin demonstrated multi-target binding and experimental inhibitory activity across all four in vitro assays. Two compounds demonstrated PAMPA-BBB permeability above the passive diffusion threshold. Molecular dynamics confirmed stable binding of strictosamide within the AChE active site gorge over 100 ns. This study proposes a novel multi-target AD pharmacophore framework grounded in Nigerian phytochemical diversity. Keywords: Alzheimer's disease, multi-target, network pharmacology, molecular dynamics, Nigerian phytochemicals