Evaluation of the antihypertensive and antidiabetic potential of peptides from the globulin fraction of quinoa (Chenopodium quinoa) by an in silico and in vitro approach

The angiotensin I converting enzyme (ACE, antihypertensive effect) and dipeptidyl peptidase IV (DPP IV, antidiabetic effect) inhibitory potential of peptides derived from the quinoa globulin hydrolysis with thermolysin were evaluated by in silico and in vitro analysis. The in silico hydrolysis of the globulin fractions resulted in peptides (~400 sequences) of different sizes and sequence conformations, of which 25 presented a high bioactivity probability score (>0.8). When the 25 sequences were evaluated for their stability against in silico simulated gastrointestinal digestion, four sequences resulted, PR, SPH, IPPG and SG all of them with a high bioactivity profile against ACE and DPP IV inhibition, where SPH and IPPG turned out to be new sequences not reported before. The molecular docking study found a high affinity between IPPG-ACE and IPPG-DPP IV and SPH-DPP IV, with several interaction points with the active sites of the enzymes evaluated. The IC₅₀ values for ACE and DPP IV found by the in vitro hydrolysis with thermolysin in a protein concentrate and in quinoa globulin support the findings of the in silico approach. Therefore, we conclude that the globulin fraction of quinoa hydrolyzed with thermolysin represents a potential source of antihypertensive and antidiabetic peptides.