A multifunctional anti-AD approach: Design, synthesis, X-ray crystal structure, biological evaluation and molecular docking of chrysin derivatives.

With the aging of the population intensifying, finding a cure or reasonable treatment for Alzheimer' disease (AD) has become an urgent priority. To target the multi-facets of AD, a class of chrysin derivatives (1-4) were rationally designed and synthesized by the multi-target-directed ligands (MTDLs) strategy, which were characterized by H NMR, C NMR, MS and elemental analysis. 1-4 showed inhibitory activities on reactive oxygen species, Aβ aggregation (self-, Cu-induced, AChE-induced). They were also potent inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) with selectivity toward BuChE. Compound 1 as the most promising candidate exhibited the highest selective BuChE inhibition (SI = 15). Furthermore, the kinetic study suggested compound 1 to be a mixed type inhibitor. The results of docking study were consistent with the in vitro results. In addition, compound 1-4 showed favorable blood-brain barrier (BBB) penetration and drug-like property in silico prediction. The corresponding copper complexes of 1-4 have also been synthesized. 1-4 selectively chelated Cu, Fe, Zn and Al ions, while had no chelating ability to other biometals. The copper complexes also showed good AChE, BuChE and reactive oxygen species inhibitory activities. Notably, the single crystals of 1-Cu(II) complex [Cu(CHNO)] were prepared for the first time and characterized by X-ray single crystal diffraction. X-ray crystallography analysis of 1-Cu(II) complex provided a reliable structure-activity insight at the molecular level about the antioxidative and Aβ disaggregation activities. Compound 1 might be a good lead compound to develop promising candidate analogs as AD therapeutics.