Potential Antioxidant Activity of Novel Antioxidant Peptides from Protein Hydrolysate of Peony Seed Dreg in Chemical and H₂O₂-Induced RAW264.7 Cells

Peony seed dreg protein (PSDP) was hydrolyzed by proteases secreted by Pseudoalteromonas sp. CSN423. This hydrolysate exhibited excellent antioxidant capability after passing through a 3 kDa ultrafiltration membrane. The antioxidant peptides further purified by size-exclusion chromatography scavenged 2, 2-diphenyl-1-picrylhydrazyl (DPPHcenter dot) (73.0 +/- 1.46%) and hydroxyl radicals (center dotOH) (81.17 +/- 3.69%), protected DNA from oxidative injury, and displayed an oxygen radical absorbance capacity (ORAC) of 4.04 +/- 1.11 mu mol TE/mg. Furthermore, the antioxidant peptide inhibited apoptosis by inhibiting the production of reactive oxygen species (ROS) and the decrease of mitochondrial membrane potential in H2O2-induced RAW264.7 cells. We identified four major peptides such as YFPF, ECCASLAPL, YVSLK, and YFEM by using mass spectrometry. YFPF showed a potent center dotOH scavenging capability of 75.30 +/- 1.08%. ECCASLAPL exhibited higher DPPHcenter dot scavenging capability (87.20 +/- 1.03%) than glutathione (GSH) (49.50 +/- 1.50%). Moreover, the peptide YVSLK exhibited the highest ORAC of 2.52 +/- 1.20 mu mol TE/mg of the identified peptides. This work highlights that the peptides from PSDP might have potential uses in cosmetics, functional foods, and drug development.