Figure 3.

Effects of natural antioxidants (polyphenolic compounds) on oxidative stress-related targets: ROS production, redox modifications and ROS-induced injury of beta cells. Oxidative stress reduces the functioning and survival of beta cells through oxidative damage and modifications of macromolecules, disruption of the antioxidant defense system and reduction of beta cell maturity genes. Thus control of oxidative stress by plant-derived preparations has a great potential in the treatment of diabetes. However, the protective effect of natural antioxidants on beta cells can be enhanced by the improvement of a current antioxidant delivery approaches. ROS/ROS, reactive oxygen and nitrogen species; Fe²⁺/Fe³⁺, ferrous ions; LP, lipid peroxidation; PG, protein glycosylation; DNA D, DNA damage; SOD, superoxide dismutase; CAT, catalase; GPx, glutathione peroxidase; GSH, glutathione; NF-kB, nuclear factor kappa B; Akt, protein kinase B; Pdx1, duodenal homeobox factor-1; MafA, musculoaponeurotic fibrosarcoma oncogene homolog A; PCNA, proliferating cell nuclear antigen; Sp1, specificity protein 1; Sirt1, Silent information regulator 1.