Synthesis and biological evaluation of quinoline/cinnamic acid hybrids as amyloid-beta aggregation inhibitors

The objective of the current study is to evaluate the potency of quinoline/cinnamic acid hybrids against amyloid-beta (Aβ) aggregation. In total, six new target quinoline/cinnamic acid hybrids were synthesized and screened for their in vitro anti-Aβ₄₂ aggregation activity. Some hybrids, including (E)-N-(2-cinnamamidoethyl)-6,7-dimethoxyquinoline-2-carboxamide, (E)-6,7-dimethoxy-N-[2-[3-(4-methoxyphenyl)acrylamido]ethyl]quinoline-2-carboxamide, and (E)-6,7-dimethoxy-N-[2-[3-(2-methoxyphenyl)acrylamido]ethyl]quinoline-2-carboxamide, showed significant anti-Aβ₄₂ aggregation activity. Molecular docking method was used to predict the binding modes of these compounds with Aβ₄₂. In addition, their cytotoxicity towards neuroblastoma SH-SY5Y and human normal hepatocyte LO2 cells were tested. Neuroprotective evaluation demonstrated that these compounds could attenuate Aβ₄₂-induced neurotoxicity towards SH-SY5Y cells in a dose-dependent manner. Overall, the present study provides quinoline/cinnamic acid hybrids as a new template for developing Aβ aggregation inhibitors against Alzheimer's disease. Graphic abstract: