Unlocking anti-tyrosinase and anti-melanogenic peptides from Torreya grandis meal hydrolysates via molecular docking, MD simulation, and experimental validation

Torreya grandis is an economically important forest tree species. As a processing by-product, Torreya grandis meal (TGM) is rich in proteins and bioactive substances. Pepsin was selected as the optimal protease for hydrolyzing TGM. The T3 fraction (< 3 kDa), which showed the strongest tyrosinase-inhibitory activity with an IC₅₀ value of 0.17 mg/mL, was obtained via ultrafiltration. Three novel tyrosinase-inhibitory peptides (LPFASW, WVPVSVE and YEVSL) were obtained through LC-MS/MS, in silico docking and cellular assays. Static molecular docking showed that all three peptides could spontaneously bind to the binuclear copper active cavity of tyrosinase 2Y9X with binding energies below -7 kcal·mol^-1, mainly through hydrophobic interactions. The 100 ns molecular dynamics simulations demonstrated that LPFASW and WVPVSVE maintained long-term binding via stable hydrogen-bond networks, whereas the hydrogen bonds of YEVSL tended to dissociate in the early simulation phase, leading to poor binding stability. In vitro tyrosinase inhibition assays gave IC₅₀ values of 232.57, 303.14, and 1009.50 μM for WVPVSVE, LPFASW, and YEVSL, respectively, consistent with MD-predicted binding stability. B16F10 cell experiments confirmed that the cell viability remained above 80% at 0-1200 μg/mL for all peptides, indicating low cytotoxicity. At 300 μg/mL, melanin content was reduced by 13.86%, 19.13% and 37.08% for YEVSL, LPFASW and WVPVSVE, respectively, while intracellular tyrosinase activity was inhibited by 33.20%, 40.64% and 18.50%, respectively. In conclusion, TGM-derived LPFASW, WVPVSVE and YEVSL possess tyrosinase-inhibitory and melanin-suppressing activities and show potential as natural functional food additives and as raw materials for cosmetics targeting pigmentation conditions.