Level of HbA1c has been reported to increase in patients with diabetes mellitus.37 The level of HbA1c is always monitored as a reliable index of glycemic control in diabetes.38 The HbA1c level is proportional to average blood glucose concentration over the previous four weeks to three months.39 In our study, treatment of diabetic rats with the leaf extract and insulin significantly decreased the HbA1c level in comparison with the positive control group. Here, INS is linked to diabetes mellitus.