Angiotensin-converting enzyme inhibitory and antioxidant peptides from digestion of larvae and pupae of Asian weaver ant, Oecophylla smaragdina, Fabricius.

Background: Mixed larvae and pupae of weaver ant (Oecophylla smaragdina) are widely used as an important food ingredient in regions of Thailand. They have high nutritional values and comprise 53% protein and 13% lipid. Peptides derived from food proteins have been shown to possess biological activities.

Results: Peptides derived from pepsin and trypsin digestion of these weaver ant larvae and pupae were purified based on angiotensin-converting enzyme (ACE) inhibitory and antioxidant activities, and their amino acid sequences were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In silico docking of peptides with ACE successfully predicted the inhibitory peptides as confirmed by their chemical synthesis. Two peptides with sequences of FFGT and LSRVP showed IC values for ACE inhibition of 19.5 ± 1.7 and 52.7 ± 4.0 µmol L , respectively. In addition, one potent antioxidant peptide with a sequence of CTKKHKPNC showed IC values of 48.2 ± 2.1 µmol L for DPPH assay and 38.4 ± 0.2 µmol L for ABTS assay, respectively.

Conclusion: These results indicate that proteins from larvae and pupae of weaver ants are potential sources of peptides with anti-ACE and antioxidation bioactivities. © 2016 Society of Chemical Industry.