Synthesis and biological evaluation of quinoxaline derivatives as ASK1 inhibitors

Inhibiting apoptosis signal-regulating kinase 1 (ASK1) presents a promising approach for treating conditions such as non-alcoholic steatohepatitis (NASH) and multiple sclerosis. In this study, we report the discovery of a dibromo-substituted quinoxaline fragment, identified as compound 26e, which acts as a potent small-molecule inhibitor of ASK1 with an IC50 of 30.17 nM. Notably, 26e exhibited a cell survival rate exceeding 80% across various concentrations, particularly at 0.4 μM, outperforming GS-4997 in terms of safety in normal human liver LO2 cells. Furthermore, Oil Red O staining demonstrated that 26e reduced lipid droplet accumulation in a dose-dependent manner. Additional biochemical analyses revealed that 26e lowered the levels of total cholesterol (T-CHO), low-density lipoprotein (LDL), and triglycerides (TG) in free fatty acid (FFA)-induced LO2 cells, suggesting its potential for managing non-alcoholic fatty liver disease. These results highlight 26e as a promising candidate for the future development of ASK1 inhibitors.