INS and type 2 diabetes mellitus: Polyphenol-based dietary antioxidants ameliorate T2D either by (1) an insulin-dependent approach, i.e., by protecting the pancreatic islet β-cell and promoting its proliferation while reducing OS and β-cell apoptosis, which causes activated insulin signaling and secretion (2) an insulin-independent approach, i.e., decreasing the intestinal absorption of glucose, inhibiting the activity of digestive enzymes and regulating glucose discharge from the liver (3) modulating intracellular signaling pathways and (4) modulating gene expression [33] (Fig. 2).