Effects of pulsed electric field on intracellular antioxidant activity and antioxidant enzyme regulating capacities of pine nut (Pinus koraiensis) peptide QDHCH in HepG2 cells

- A novel antioxidant peptide QDHCH was identified using HPLC-MS/MS.
- The antioxidant activity of QDHCH was increased by PEF treatment.
- The PEF-treated QDHCH have better protective oxidative stress inhibitory.
- The secondary structures of QDHCH were influenced by PEF treatment.

Effects of pulse electric field (PEF) on antioxidant activity of pine nut (Pinus koraiensis) peptide were discussed using H2O2-induced HepG2 cells and changes of peptide structures were measured by MIR, NMR and CD spectra. Using HPLC-MS/MS, a novel peptide was identified as QDHCH. After PEF treatment the DPPH and ABTS radical inhibition, and CAA values of QDHCH were increased to 85.13% ± 0.17%, 95.45% ± 0.12%, and 4670.10 μmol of quercetin equivalents/100 g. The PEF-treated QDHCH has better protective oxidative stress inhibitory of 74.22 ± 3.70%, and the T-SOD, CAT, GSH-Px and GSH-Rx activities in cells were significantly increased by 91.92, 7.98, 18.5 and 18.79 U/mg prot, while the MDA content was decreased to 8.45 ± 0.71 U/mg prot compared with H2O2 damaged group. In addition, the hydroxyl radical scavenging activity of QDHCH was increased by 10.53%; the basic structure was not changed by PEF, while the influenced secondary structures may induce the antioxidant activity improvement in HepG2 cells.