Modification of soluble dietary fiber from quinoa bran and investigation of its anticancer activity in vitro

Abstract BACKGROUND To investigate the immunological and anticancer actions of quinoa bran soluble dietary fiber (SDF), this study used a simple approach to develop an SDF–zinc complex (SDF‐Zn) to enhance the biological activity of SDF. SDF‐Zn was co‐cultured with NK cells to investigate its ability to activate NK cells. Then, its ability to induce apoptosis in HepG2 human hepatoma cells was investigated using cell proliferation, scratch wound healing assay, flow cytometry, real‐time polymerase chain reaction and western blot. RESULTS The results revealed that chelating SDF and zinc ions considerably increased the cytotoxicity of NK cells against HeLa cells (48.76% at 150 μg mL −1 ) and significantly ( P  < 0.05) increased the levels of IFN‐ γ , TNF‐ α , granzyme‐B and NKp44. SDF‐Zn was co‐cultured with common human cancer cells including AGS, HeLa, HCT116 and HepG2, and the results revealed that SDF‐Zn significantly ( P  < 0.05) inhibited HepG2 cell proliferation. The overproduction of reactive oxygen species increased the expression of apoptotic genes including Bax and caspase‐3, and the number of dead cells reached 45.91%. The inhibitory effect of SDF‐Zn on HepG2 cells occurred through the MAPK and NF‐ κ B signaling pathways. CONCLUSION Overall, the SDF‐Zn complex has the potential to be used as a therapeutic agent for human liver cancer. © 2025 Society of Chemical Industry.