Design And Evaluation Of Four Novel Tripeptidcs As Potent Angiotensin Converting Enzyme(ACE) Inhibitors With Activity

Objective:Angiotensin-converting enzyme(ACE)inhibitory peptides have attracted more and more attention due to their fewer side effects.Here,we aimed to investigate the antihypertension activity of 4 synthetic tripeptides(theanine(Thea)-theanine(Thea)-proline(pro),TTP;y-aminobutyric acid(GABA)-theanine(Thea)-proline(pro),gATP;y-aminobutyric acid(GABA)-y-aminobutyric acid(GABA)-proline(pro),gAgAP;theanine(Thea)-?-aminobutyric acid(GABA)-proline(pro),(TgAP)in vitro and in vivo.Methods:The ACE inhibitory activity and mode were analyzed with a modified spectrophotometric method and Lineweaver-Burk plots,respectively.Molecular docking simulations were performed using the AutoDock Vina software.Cell activity was detected by cck-8 method.Blood pressure of spontaneously hypertensive rats(SHRs)was monitored by the tail-cuff method,and gene expression were evaluated by real-time PCR.Results:Tripeptides TTP and gAgAP showed promising ACEI activities,with IC50 of 0.92 and 3.4 ?mol/L,respectively.The inhibition modes of tripeptide TTP and gAgAP were competitive with Ki values of 0.87 and 3.12 ?mol/L.TTP and gAgAP could form several critical hydrogen bonds with the active site residues of ACE.TTP and gAgAP treatments had little effect on the HUVEC activity,but induced rapid and significant reductions of systolic blood pressure(SBP)in SHRs.Moreover,TTP treatment led to a comparable reduction of agtrl levels but a significantly lower expression of miR-132/212 when compared with captopril treatment.Conclusion:These results evident that compound TTP might serve as a potential candidate for hypertension treatment.