Rational design, synthesis and activities of hydroxylated chalcones as highly potent dual functional agents against Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the extracellular amyloid plaques in the brain. Recent studies have shown that ferroptosis, a recently identified cell death pathway associated with the accumulation of lipid hydroperoxides, is closely related to the occurrence and exacerbation of AD. The application of ferroptosis inhibitors can alleviate the development of AD in both cellular and animal models. Herein, a series of dual-functional hydroxylated chalcone derivatives by integrating the heterocyclic dimethylaminopyrimidine in the core structure were designed and synthesized beyond our previous research to optimize their inhibition activities towards Aβ protein aggregation and ferroptosis simultaneously. The inhibitory ability of the novel synthesized chalcone derivatives were greatly improved. The results indicated that the introduction of the dimethylaminopyrimidine structure provided improved effect on Aβ protein aggregation inhibitory activity in both solution and cellular models. Trihydroxy chalcone derivative A-N-5 provided the best inhibition activities against Aβ protein aggregation in cellular models. The trihydroxy compound A-N-5 did not show cytotoxicity at the concentration lower than 100 µM (with IC₅₀ > 1 mM), but had a significant effect on promoting cell proliferation. Results indicated that compound A-N-5 could potentially promote neuronal cell growth in the damaged brain tissue. The compound could also inhibit ferroptosis induced by RSL or erastin and reduce the lipid peroxidation levels induced by Aβ_1-42 protein aggregation. Molecular docking was also conducted to explain the better inhibitory effect of novel compounds to inhibit Aβ protein aggregation compared to the previous designed molecules without incorporation of the dimethylaminopyrimidine. In summary, the trihydroxy compound A-N-5 showed the best inhibition activities against Aβ aggregation as well as ferroptosis with low cytotoxicity as a promising molecular skeleton candidate for further development of lead compound for in vivo test to treat AD.