Selective Cytotoxicity of Sodium Enone Salts Through Mitochondrial Dysfunction and Cell Cycle Arrest in Human Cancer Cells

Recent advances in enone chemistry have enabled the development of structurally optimized derivatives with improved anticancer selectivity. In this study, the cytotoxic activity and underlying mechanisms of sodium salts of four α,β-unsaturated enones (ES1–ES4), synthesized from vanillin-based scaffolds, were evaluated in human colorectal carcinoma (HCT-116), cervical adenocarcinoma (HeLa), and normal lung fibroblast (MRC-5) cell lines. All compounds exhibited concentration- and time-dependent cytotoxicity, with ES2 showing the highest potency (IC50 = 14.25 μM in HCT-116 and 18.12 μM in HeLa at 72 h) and minimal toxicity toward MRC-5 cells (IC50 > 90 μM). Although cisplatin demonstrated greater overall cytotoxicity, the enone salts displayed significantly higher selectivity indices, indicating a more favorable therapeutic window. Phase-contrast microscopy revealed characteristic morphological features of apoptosis, including cell rounding and membrane blebbing. Mechanistic investigations confirmed mitochondrial-mediated apoptosis, evidenced by increased early and late apoptotic populations, Bax upregulation, Bcl-2 downregulation, and caspase-3 activation. JC-10 staining demonstrated mitochondrial membrane depolarization accompanied by cytochrome c release. In addition, cell cycle analysis revealed pronounced G2/M phase arrest, particularly in HCT-116 cells. Collectively, these findings indicate that vanillin-derived enone sodium salts exert selective anticancer effects through mitochondrial apoptosis and cell cycle disruption, supporting their potential as low-toxicity anticancer candidates.