We also wondered whether okanin could alter the protein spebility/level of PRDX5, Indeed, okanin reduced the protein level of PRDX5 in a concentration‐dependent manner not only in HCT116 (Figure4A; Figure S3A, Supporting Information) and SW480 colorectal cancer cells (Figure S3B, Supporting Information), but also in MCF7 breast cancer and HepG2 liver cancer cells (Figure 4B; Figure S3C, Supporting Information), without altering the protein levels of other PRDX family members (Figure S3D,E, Supporting Information). Here, PRDX5 is linked to colorectal cancer.