Bioactivities of In Vitro Transepithelial Transported Peptides from Cooked Chicken Breast

Bioactivities including cellular antioxidant activity in HepG2 and dipeptidylpeptidase-IV inhibitory effect of in vitro transepithelial transported peptides with ACE inhibitory activity from cooked chicken breast, namely, APP, KP, KPLL, LL, LVK and LVQ were investigated. HepG2 cells were the most susceptible to KP, however, none of them were toxic up to 100 mu M. KP and KPLL showed cytoprotective effect and could reduce intracellular reactive oxygen species (ROS) level in a dose-dependent response (P < 0.05), particularly 100 mu M KP showed comparable capacity with 100 mu M ascorbic acid as demonstrated by using 2MODIFIER LETTER PRIME,7MODIFIER LETTER PRIME-dichlorofluorescein-diacetate (DCFH-DA) probe. KP induced expression of SOD1 and GPX1, while CAT appeared to be upregulated by KPLL (P < 0.05). Among the peptides studied, LL with an IC50 of 4.79 mM was the most active peptide against DPP-IV activity through a non-competitive action (K-i = 922.96 mu M) as demonstrated by the Lineweaver-Burk plot, suggesting the ability of LL to bind with DPP-IV at various locations other than active site. Molecular docking revealed that LL interacted with the enzyme via van der Waals, salt bridge interactions, and hydrogen bonds.

Automated summary

The bioactivities of peptides APP, KP, KPLL, LL, LVK, and LVQ from cooked chicken breast were investigated, including their cellular antioxidant activity and inhibitory effect on DPP-IV. KP and KPLL showed cytoprotective effects and reduced intracellular reactive oxygen species levels, while LL exhibited the highest inhibitory activity against DPP-IV.