Identification and molecular mechanism of novel tyrosinase inhibitory peptides from the hydrolysate of 'Fengdan' peony (Paeonia ostii) seed meal proteins: Peptidomics and in silico analysis

Natural and potent tyrosinase inhibitors are in high demand in the food, cosmetic, and pharmaceutical industries. In this study, the hydrolysate was prepared from the peony (Paeonia ostii) seed meal proteins (PSMP) by Neutrase with high tyrosinase inhibitory activity. The peptide profile analysis exhibited that there were 594 peptides from 28 proteins, among which 39 peptides were predicted to have high bioactivity, good solubility, and non-toxicity, and were suitable for oral or topical administration by in silico analysis. Molecular docking demonstrated that 38 of the 39 peptides can be promising tyrosinase inhibitors as they had lower or the same binding energies as the tyrosinase inhibitor kojic acid. The interaction mechanism analysis for the top 3 potent peptides demonstrated that 5 out of 8 catalytic residues were involved in each interaction, in which hydrogen bonding was crucial for the peptide SFAPRFD, and both hydrogen bonding and hydrophobic interaction were important for peptides HYGR and SPGRLP. As demonstrated by in vitro test, these three peptides were potent tyrosinase inhibitors with IC50 ranging from 0.95 to 1.58 mmol/L. Our findings highlight that PSMP can be a valuable source of natural tyrosinase inhibitory peptides for various industrial applications.