In vivo superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in the kidney cortex were diminished in diabetes mellitus (DM) rats, which contrasted with the control normoglycemic rats; the administration of the methanol extract of leaves of B. cordata effectively prevented the decrease in SOD and GPx with a dose of 100 mg/kg (p < 0.05, respectively). The gene discussed is SOD1; the disease is diabetes mellitus.