Identification, functional gastrointestinal stability and molecular docking studies of lentil peptides with dual antioxidant and angiotensin I converting enzyme inhibitory activities

- Lentil peptides showing potential antihypertensive activity were identified.
- Bioactive fragments derived from lentil vicilin, convicilin and legumin.
- Gastrointestinal digestion of peptides improved markedly their bioactivity.
- C-terminal heptapeptide was crucial for antioxidant and ACE inhibitory activities.
- ACE inhibition relies on hydrogen bonds involving residues of the catalytic site.

The objective was to identify peptides with dual antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities released from lentil proteins by Savinase®. The influence of gastrointestinal digestion on peptide bioactivity was also assayed. Fragments from vicilin, convicilin and legumin were the most abundant peptides identified. Peptides LLSGTQNQPSFLSGF, NSLTLPILRYL, TLEPNSVFLPVLLH showed the highest antioxidant (0.013-1.432 μmol Trolox eq./μmol peptide) and ACE inhibitory activities (IC50 = 44-120 μM). Gastrointestinal digestion of peptides improved their dual activity (10-14 μmol Trolox eq./μmol peptide; IC50 = 11-21 μM). In general, C-terminal heptapeptide was crucial for their dual activity. ACE inhibition relies on the formation of hydrogen bonds between C-terminal residues of lentil peptides and residues of the ACE catalytic site. The present study helps clarifying the relationship between structure and dual antioxidant/antihypertensive activity of lentil peptides opening new opportunities to food industry such as the application of lentil protein hydrolysates as ingredients for development of functional foods.