Diabetes mellitus (DM) is a chronic metabolic disorder characterized by high levels of glucose in blood due to non-secretion of insulin or insulin insensitivity. However, different types of DM are available. Out of these, type 1 diabetes mellitus (Type 1 DM) and type 2 diabetes mellitus (Type 2 DM) are now recognized as serious global health problem, growing rapidly worldwide and taking its place as one of the main threats to human health in the 21st century. The International Diabetes Federation (IDF) estimated that, the developing countries like India, already top of the diabetic league. Now a day, more than 90% of diabetic patients suffer from type 2 DM, which is characterized by insulin resistance and hyperglycemia. Several epidemiological and clinical studies indicate a direct relationship between hyperglycemia and long term microvascular and macrovascular complications, which develop as the disease progresses, gradually decrease quality of life of diabetic patients. Therefore, it is essential to control blood glucose levels during the early stages of the disease. Therapy for DM primarily has been aimed at improving glycemic control via a combination of diet, exercise and current therapeutic agents such as insulin formulations, sulfonylureas, metformin, acarbose, thiazolidine-2,4-diones, glucagon like peptide-1 analog and dipeptidyl peptidase-4 or IV inhibitors.