XDH and type 2 diabetes mellitus: Metformin also reduces oxidative stress markers (MDA, TBARS, and NO, lipid peroxidation and xanthine-oxidase activity) [187, 195, 197], and improves brain antioxidant capacity by increasing SOD activity in the hypothalamus and hippocampus from T2D rats [197], while boosting citrate synthase and COX activities in HFD-fed mice [196].