In vitro and in silico studies of antioxidant peptides from tarwi (Lupinus mutabilis) as inhibitors of angiotensin-converting enzyme and dipeptidyl peptidase IV enzyme

The present research aimed to evaluate three peptides synthesised from tarwi: AVPFWM, YSGWLGL and AHAGFGMLY in their antioxidant, antihypertensive and hypoglycemic properties, using in vitro and in silico studies, this last one considering the molecular docking evaluation and ADMET (absorption, distribution, metabolism, excretion and toxicity) properties. The in vitro results found ABTS and ORAC antioxidant capacity values between 2.12 and 3.94 and 1.64 and 3.10 μmol TE/μmol of peptide, respectively, while the IC₅₀ values for angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibition ranged between 0.14 and 6.38 μM and 16.4 and 1140.0 μM, respectively. The molecular docking study performed between peptides and ACE and DPP-IV enzymes, showed affinity towards both enzymes establishing molecular interactions at the level of the active site of both enzymes through hydrogen bonds and hydrophobic interactions. This study together with the in vitro study highlight the YSGWLGL peptide for the favourable results found. Finally, the predicted ADMET properties of the three peptides suggest that they have the potential for absorption, appropriate distribution, no participation in the metabolism of P450 enzymes and no toxicity concerns. It is concluded that tarwi peptides may be a valuable source for developing nutraceuticals, functional ingredients or supplements.