In vitro and in silico study of multitarget amaranth antihypertensive peptides

AGUSTINA E. NARDO; SANTIAGO E. SUAREZ; ALEJANDRA V. QUIROGA; AÑON MARÍA CRISTINA

Rio de Janeiro

Conferencia; IX International Conference on Food Proteins and Colloids (CIPCA 2023); 2023

Hypertension is characterized by an insufficient vessel relaxation and reduced blood flow. The main system involved in the regulation of blood pressure is the reninangiotensin system (RAS) regulated mainly by two enzymes: renin and the angiotensin converting enzyme (ACE). One of the strategies used to reduce blood pressure is to encourage changes in habits, for example, by incorporating into diet ingredients that contribute to preserve and maintain health. In this regard food protein derivate bioactive peptides have been widely studied, especially in terms of their antihypertensive effect. There is evidence in the literature of peptides that exhibit more than one activity or that may even be active against two or more molecular targets(enzymes). Amaranth grain proteins are an excellent source of antihypertensive peptides. The aim of this work was determined if amaranth peptides have a possible double target of action (ACE and Renin inhibition), as well as to evaluate in silicowhether they are resistant to gastrointestinal digestion. Besides, identify by molecular docking if the sequence patterns that inhibit one enzyme or another are similar or different. We work with 3 Renin inhibitor peptides identified and characterized in our laboratory: SFNLPILR, FNLPILR and AFEDGFEWVSFK. The percentage of ACE inhibitory capacity of these three peptides was determined in vitro and to the most potent inhibitors, the IC50 values were calculated by dose–response curves.Resistance to digestive enzymes was assessed using different bioinformatics tools: BIOPEP-UWM (https://biochemia.uwm.edu.pl/biopep-uwm/) and PeptideCutter (https://web.expasy.org/peptide_cutter) and docking analyses for the most active peptides were performed with CABS-dock (http://biocomp.chem.uw.edu.pl/CABSdock) to propose an interaction mechanism.All peptides tested were able to inhibit ACE. SFNLPILR and FNLPILR showed the highest percentage of inhibition, reaching a 90% of inhibition at a concentration of 0.125 mg/ml. The IC50 value was 0.081 mg/ml (95% CI, 0.032-0.21) and 0.053 mg/ml (95% CI, 0.019-0.15) respectively.According to docking analysis the most active peptides are able to access to the active site of ACE. By comparing our sequences with sequences reported in bioactive peptide databases, both share the IL sequence motif which has ACE inhibitor activity (IC50 0.054 mM). But the whole peptides had not previously been evaluated as ACE inhibitors. Regarding the theoretical analysis of resistance to digestive enzyme action, the three peptides are degraded into di- and tri-peptides by Pepsin action, which indicates that in case of using them as active ingredients it is necessary to design protection strategies, although their hydrolysis products could be active too.These results show that amaranth is a source of antihypertensive peptides with more than one possible target of action. Therefore, amaranth proteins could be a functional ingredient with potential antihypertensive activity in vivo that would improve the quality life of the population affected by hypertension disease.