Alzheimer's disease is likely to be caused by copathogenic factors including aggregation of Aβ peptides into oligomers and fibrils, neuroinflammation, and oxidative stress. To date, no effective treatments are available, and because of the multifactorial nature of the disease, it emerges the need to act on different and simultaneous fronts. Despite the multiple biological activities ascribed to curcumin as neuroprotector, its poor bioavailability and toxicity limit the success in clinical outcomes. To tackle Alzheimer's disease on these aspects, the curcumin template was suitably modified and a small set of analogues was attained. In particular, derivative 1 turned out to be less toxic than curcumin. As evidenced by capillary electrophoresis and transmission electron microscopy studies, 1 proved to inhibit the formation of large toxic Aβ oligomers, by shifting the equilibrium toward smaller nontoxic assemblies and to limit the formation of insoluble fibrils. These findings were supported by molecular docking and steered molecular dynamics simulations which confirmed the superior capacity of 1 to bind Aβ structures of different complexity. Remarkably, 1 also showed in vitro anti-inflammatory and antioxidant properties. In summary, the curcumin-based analogue 1 emerged as multipotent compound worthy to be further investigated and exploited in the Alzheimer's disease multitarget context.
Keywords: Alzheimer’s disease; amyloid beta oligomers and fibrils; capillary electrophoresis; curcumin analogues; neuroinflammation; oxidative stress.