DPP4 and diabetes mellitus: Synthetic inhibitors of DPP-IV and/or ACE are the first-line option for the treatment of these events (6), however, inevitable and evitable side effects of them, such as coughing, skin rashes, taste disturbances, angioedema, hyperkalaemia (ACE inhibitors) (7, 8), and nasopharyngitis, headache, diarrhea, joint pain, urinary tract infection (DPP-IV inhibitors) (9, 10), highlight the importance of developing new natural, innovative side-effect free compounds to prevent and/or alleviate diabetes and hypertension.