Antioxidant and Angiotensin I Converting Enzyme (ACE) Inhibitory Properties of GL‐9 Peptide

The aim of this study was to examine antioxidant and inhibitory activity of Gly‐Ala‐Ser‐Arg‐His‐Trp‐Tyr‐Phe‐Leu peptide named GL‐9 peptide. The synthetic GL‐9 peptide was purified by C8 reveres phase HPLC (RP‐HPLC). The antioxidant activity of the GL‐9 peptide was investigated based on its scavenging capacity1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical, 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulphonic acid) diammonium salt (ABTS), superoxide ( O2•−), hydroxyl (OH•−) and lipid peroxidation inhibition. The ACE inhibitory activity and kinetic parameters of the peptide were determined using FAPPG as substrate. GL‐9 peptide/ACE complex interaction, position, type and energy was also investigated by using molecular docking. GL‐9 peptide displays DPPH (IC50 = 6.5 µg/mL), ABTS•+ (IC50 = 7.2 µg/mL), superoxide (IC50 = 122 µg/mL) and hydroxyl (IC50 = 60.0 µg/mL) radical scavengers. GL‐9 peptide showed an IC50 value of 47.8 µg/mL which inhibited ACE activity. The results indicated that the GL‐9 peptide has antioxidant and ACE inhibitory capacity. Practical Applications Synthetic GL‐9 peptide antioxidant and anti‐hypertensive activity were investigated using in vitro assays. Results indicated that this peptide possesses a high potent antioxidant activity as well as ACE‐inhibitory activity, demonstrate its potential application as an ingredient in wholesome foodstuffs.