Insights into the mechanism of groove binding between 4–octylphenol and calf thymus DNA

4–Octylphenol is an endocrine disruptor , belonging to environmental estrogens. It can be enriched in the human body through the food chain and may harm human health. Herein, we used a variety of spectroscopic techniques, molecular docking, and gel electrophoresis to study the interaction of 4–octylphenol and ctDNA . It was found that the mechanism of ctDNA quenching the endogenous fluorescence of 4–octylphenol was static quenching, and formed a complex. The negative enthalpy change (Δ H °), entropy change (Δ S °) and Gibbs free energy (Δ G °) have shown that 4–octylphenol and ctDNA spontaneously bind together under the action of hydrogen bonds and van der Waal's force . Viscosity, melting temperature and iodide quenching experiments showed that 4–octylphenol acted on the groove of ctDNA. Insignificant change in circular dichromism spectra further confirmed this binding mode. The binding sites and groups for 4–octylphenol and ctDNA interaction were identified by molecular docking. Gel electrophoresis found that 4–octylphenol at high concentrations caused DNA cleavage. Above findings may lay a theoretical foundation for understanding the toxicity mechanism of 4–octylphenol.