Effects of white mulberry (Morus alba) leaf tea investigated in a type 2 diabetes model of rats.nigra L. pulp or leaf extracts, respectively. At the end of treatment, animals were euthanized and, liver and blood samples were collected for analysis of biochemical and metabolic parameters. Our study demonstrated that treatment of diabetic rats with leaf extracts decreased the superoxide dismutase (SOD)/catalase (CAT) ratio and carbonylated protein levels by reducing oxidative stress. Moreover, the leaf extract of M. nigra L. decreased the matrix metalloproteinase (MMP)-2 activity, increased insulinemia, and alleviated hyperglycemia-induced diabetes. In conclusion, our study found that the leaf extract of M. nigra L. improved oxidative stress and complications in diabetic rats, suggesting the utility of this herbal remedy in the prevention and treatment of DM.