Interaction of isoeugenol with calf thymus DNA and its protective effect on DNA oxidative damage

Abstract Isoeugenol, a natural phenolic compound in plant essential oils, is known to have many biological and pharmacological properties. In the present work, the interaction of isoeugenol with calf thymus DNA (ctDNA) and its protective effect on DNA oxidative damage were investigated by multispectroscopic techniques, viscosity measurements, gel electrophoresis studies and molecular simulation. Analyses of ultraviolet-visible (UV–vis) absorption and fluorescence spectra indicated that isoeugenol could bind to ctDNA with a binding constant on the order of 10 3  L mol −1 , which was mainly driven by hydrogen bonding and van der Waals forces. The results from the viscosity measurements, competitive displacement studies and circular dichroism (CD) analysis indicated that the binding of isoeugenol to ctDNA was in the groove mode and that the A–T base pairs in the minor grooves of ctDNA were the main binding sites for isoeugenol, which was supported by molecular docking analyses. In addition, isoeugenol was found to show a protective effect against hydroxyl-induced DNA damage, which may be explained by its good antioxidant activity. These findings may improve the understanding of the mechanism of interaction between isoeugenol and ctDNA and provide a theoretical basis for the development of isoeugenol in the food and drug industry.