INS and diabetes mellitus: Although curcumin has been reported to inhibit high glucose-induced proliferation of human retinal endothelial cell (Premanand et al., 2006) and also display beneficial impacts on diabetes-induced endothelial dysfunction (Patumraj et al., 2006; Rungseesantivanon et al., 2010; Nabavi et al., 2015), the potential impacts of curcumin on insulin resistance of vascular endothelial cells and its underlying mechanism(s) remain poorly understood.