Tryptic amaranth glutelin digests induce endothelial nitric oxide production through inhibition of ACE: Antihypertensive role of amaranth peptides

• Published in: Nitric oxide Vol. 23; no. 2; pp. 106 - 111
• Main Authors: Barba de la Rosa, A.P., Barba Montoya, A., Martínez-Cuevas, Pedro, Hernández-Ledesma, B., León-Galván, M.F., De León-Rodríguez, A., González, C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.09.2010
• Subjects: ACE; Amaranthus - chemistry; Angiotensin converting enzyme inhibition; Angiotensin-Converting Enzyme Inhibitors - pharmacology; Animals; Antihypertensive Agents - pharmacology; Antihypertensive plant peptides; Aorta - cytology; Aorta - metabolism; Cell Proliferation - drug effects; Cells, Cultured; Coronary endothelial cells; Coronary Vessels - cytology; Coronary Vessels - metabolism; Endothelium, Vascular - cytology; Endothelium, Vascular - metabolism; Glutens - metabolism; Glutens - pharmacology; IC 50; Male; Nitric Oxide - biosynthesis; Peptides - chemistry; Peptidyl-Dipeptidase A - metabolism; Plant Proteins - chemistry; Rats; Rats, Sprague-Dawley; Time Factors; Trypsin - metabolism; Vascular relaxation; Antihypertensive plant peptides; IC 50; ACE; Coronary endothelial cells; Angiotensin converting enzyme inhibition; Vascular relaxation
• ISSN: 1089-8603; 1089-8611
• DOI: 10.1016/j.niox.2010.04.006

Amaranth seed proteins have a better balance of essential amino acids than cereals and legumes. In addition, the tryptic hydrolysis of amaranth proteins generates, among other peptides, angiotensin converting enzyme (ACE) inhibitory (ACEi) peptides. ACE converts angiotensin I (Ang I) into Ang II, but is also responsible for the degradation of bradykinin (BK). In contrast to Ang II, BK stimulates vasodilation modulated through endothelial nitric oxide (NO) production. The aim of the present study was to characterize the ACEi activity of amaranth trypsin-digested glutelins (TDGs) and their ability to induce endothelial NO production. An IC 50 value of 200 μg ml −1 was measured for TDG inhibition of ACE. TDGs stimulated endothelial NO production in coronary endothelial cells (CEC) by 52% compared to control. The effects of TDGs were comparable to those of BK and Captopril, both used as positive controls of NO production. Consistent with these effects, TDGs induced, in a dose-dependent manner, endothelial NO-dependent vasodilation in isolated rat aortic rings. These results suggest that TDGs induce endothelial NO production and consequent vasodilation through their ACEi activity. Amaranth TDGs have a high potential as a nutraceutical food in prevention of cardiovascular diseases. Further molecular, cellular and physiological studies are currently under way and the results may contribute to a better understanding and control of cardiovascular disorders.