Hypotensive effect of potent angiotensin-I-converting enzyme inhibitory peptides from corn gluten meal hydrolysate: Gastrointestinal digestion and transepithelial transportation modifications

The study examined the antihypertensive effect of peptides derived from pepsin-hydrolyzed corn gluten meal, namely KQLLGY and PPYPW, and their in silico gastrointestinal tract digested fragments, KQL and PPY, respectively. KQLLGY and PPYPW showed higher angiotensin I-converting enzyme (ACE)-inhibitory activity and lower ACE inhibition constant (Ki) values when compared to KQL and PPY. Only KQL showed a mild antihypertensive effect in spontaneously hypertensive rats with −7.83 and − 5.71 mmHg systolic and diastolic blood pressure values, respectively, after 8 h oral administration. During passage through Caco-2 cells, KQL was further degraded to QL, which had reduced ACE inhibitory activity. In addition, molecular dynamics revealed that the QL-ACE complex was less stable compared to the KQL-ACE. This study reveals that structural transformation during peptide permeation plays a vital role in attenuating antihypertensive effect of the ACE inhibitor peptide. •KQLLGY and PPYPW are ACE inhibitors isolated from pepsin-hydrolyzed corn gluten meal.•In silico digestion of these peptides generated weaker fragments against ACE.•KQLLGY and PPYPW did not show in vivo antihypertensive effect in SHR.•KQL, a fragment of KQLLGY digestion, showed mild antihypertensive effect.•KQL was degraded to QL during passage through the Caco-2 cell monolayer.•Molecular dynamic revealed lower stability of the QL-ACE complex than the KQL-ACE.