SOD1 and diabetes mellitus: As Figure 4 shows, at the end day of the study, there were increased MDA levels (diabetes vs. control, p < 0.01), decreased SOD, GPX and CAT activities (diabetes vs. control, p < 0.01) in diabetic group, after CS or metformin administration the levels of MAD decreased (CS vs. diabetes, p < 0.01, Met vs. diabetes, p < 0.01), the SOD, GPX, and CAT activities increased (CS vs. diabetes, p < 0.01, Met vs. diabetes, p < 0.01).