Isolation and identification of anti-colorectal cancer peptides from walnut proteins and associated in silico analysis

Walnut protein-derived peptides have a variety of biological activities, but it is unclear whether walnut peptides have anti-colorectal cancer activity. Therefore, the aim of this study was to explore the anti-colorectal cancer peptides of walnut and the underlying mechanism of action by in silico analysis and in vitro evaluation. Walnut protein alcalase hydrolysate (WPH-Al) significantly inhibited the growth and induced the apoptosis of colon cancer HCT116 cells. The < 1 kDa molecular weight fraction (WPH-M1) exhibited more significant inhibition of HCT116 cell proliferation and induction of apoptosis than other fractions. In silico analysis identified three peptides (PISLKSE, VSLP, and SHTLP) in WPH-M1 with potential anticancer activity. Network pharmacology analysis further identified 72 targets of these peptides associated with colorectal cancer, which were mainly enriched in pathways related to cancer and apoptosis, among which caspase-3 (CASP3) and metalloproteinase-9 (MMP9) were identified as candidate core targets. These results were verified by molecular docking. Overall, these screened walnut-derived peptides may represent a promising functional food with anti-colorectal cancer effects.