Synthesis, characterization, cytotoxicity, intracellular ros production and detection of inhibitory effects on inflammation mediators of novel hexahydroquinoline derivatives

In this study, 15 new hexahydroquinoline derivative compounds with the general structure of alkyl 2-methyl/2,6,6/2,7,7-trimethyl-4-(4-difluoromethoxyphenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, a condensed derivative of 1,4-DHP, which is expected to show inhibitory activity on inflammatory mediators, were synthesized. The compounds were obtained by reaction of 4-(difluoromethoxy)benzaldehyde, substituted/non-substituted 1,3-cyclohexadione derivatives and appropriate alkyl acetoacetate derivatives in the presence of ammonium acetate as nitrogen source according to Hantszch synthesis method. The structures of the synthesized compounds were elucidated by IR, 1H-NMR, 13C-NMR and HRMS methods. X-ray diagrams of some compounds with suitable crystal forms were taken. The cytotoxic properties of the compounds were examined by MTT method in 3T3 cell line. Among the 15 compounds, 3 compounds with the least decrease in cell viability were selected for further experiments. The effects of the selected compounds on the levels of reactive oxygen species (ROS), cytokines, complement pathway c3 and c9 regulatory proteins as a result of lipooxygenase (LPS)-induced inflammation in the 3T3 cell line were investigated. It was found that all three selected compounds statistically significantly decreased TGF-1 levels and compound 3e was the most active compound on this cytokine. In addition, all three compounds statistically significantly increased the level of IL-1 and compound 3b was found to have the highest activity on this cytokine. Molecular docking studies were performed to determine the interaction of Compound 3b with molecular targets.