• Induces DNA damage, promotes the accumulation of RAD51 at DNA DSB sites and regulates HR in cells.• Single agent activity in a broad spectrum of cancer cells and enhances the sensitivity of colorectal cancer cells to RAD51 inhibitor, RI-1 and cisplatin by inducing synthetic lethality.IC50 = 2-25 μM. This evidence concerns the gene RAD51 and colorectal cancer.