Chromone–lipoic acid conjugate: Neuroprotective agent having acceptable butyrylcholinesterase inhibition, antioxidant and copper-chelation activities

Alzheimer’s disease (AD) is a multifaceted neurodegenerative disease. To target simultaneously multiple pathologicalprocesses involved in AD, natural-origin compounds with unique characteristics are promising scaffolds to develop novel multitarget compounds in the treatment of different neurodegenerative disease, especially AD. In this study, novel chromone-lipoic acid hybrids were prepared to find a new multifunctional lead structure for the treatment of AD. Methods Chromone-lipoic acid hybrids were prepared through click reaction and their neuroprotection and anticholinesterase activity were fully evaluated. The anti-amyloid aggregation, antioxidant and metal-chelation activities of the best compound were also investigated by standard methods to find a new multi-functional agent against AD. Results The primary biological screening demonstrated that all compounds had significant neuroprotection activity against H2O2-induced cell damage in PC12 cells. Compound 19 as the most potent butyrylcholinesterase (BuChE) inhibitor (IC50 =7.55 μM) having significant neuroprotection activity as level as reference drug was selected for further biological evaluations.Docking and kinetic studies revealed non-competitive mixed-type inhibition of BuChE by compound 19. It could significantlyreduce formation of the intracellular reactive oxygen species (ROS) and showed excellent reducing power (85.57 mM Fe+2), comparable with quercetin and lipoic acid. It could also moderately inhibit Aβ aggregation and selectively chelate with copperions in 2:1 M ratio.Conclusion Compound 19 could be considered as a hopeful multifunctional agent for the further development gainst AD owingto the acceptable neuroprotective and anti-BuChE activity, moderate anti-Aβ aggregation activity, outstanding antioxidant activity as well as selective copper chelation ability.