Preparation, Identification, and Cellular Antioxidant Activity Evaluation of Antioxidant Peptides From the Antler Tips of Sika Deer (Cervus nippon)

Abstract

A process for extracting the antler tip peptides (ATPs) from Sika deer (Cervus nippon) antler tips was optimized using a method that combines single-factor experiment and response surface methodology. The optimal conditions involved papain as the hydrolase, an enzyme concentration of 5000 U/g, a hydrolysis time of 3.0 h, a temperature of 52.0°C, a pH of 7.10, and a substrate concentration of 14%. Under these conditions, the clearance rate of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was 73.05 ± 1.49%, and the degree of hydrolysis (DH) was 19.43 ± 1.06%. The antioxidant compound ATPs-2 exhibited strong free radical and anion scavenging activity. In a model of Ultraviolet B (UVB)-induced oxidative damage, ATP-2 reduced reactive oxygen species (ROS) and malondialdehyde (MDA) levels, increased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities, and alleviated UVB-induced cellular oxidative damage. A total of 6279 unique peptide sequences were identified in ATP-2, with 2496 potential bioactive peptides predicted using PeptideRanker. Of these, 12 peptides with PeptideRanker scores above 0.95 were analyzed using BIOPEP-UWM, identifying three antioxidant peptides: GPWPPGAP, GPAGPPGGPGL, and PGSPGPPGMPGP. Among them, GPWPPGAP displayed the highest antioxidant activity, with an IC₅₀ value on DPPH radical of 1.1 mg/mL and a strong binding energy of −9.8 kcal/mol to MMP-1.