Administration of rosemary essential oil enhances resistance of rat hepatocytes against DNA-damaging oxidative agents

The aim of this paper was to evaluate the potential DNA-protective effects of rosemary essential oil-supplementation on rat hepatocytes damaged with three different genotoxins attacking DNA by oxidative stress. Hydrogen peroxide (H2O2) reacts by the generation of hydroxyl radicals, visible light-excited methylene blue forms oxidative DNA lesions via singlet oxygen and 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) induces oxidative stress by participation in redox cycling. Hepatocytes were isolated from rats supplemented with rosemary oil (RO) for 14 days as well as from control rats. The potential protective effects of RO applied in drinking water of animals were tested on the level of DNA using the conventional and modified single cell gel electrophoresis (comet assay). We found out that administration to rats of rosemary oil, exhibiting free radical-scavenging activity measured by DPPH assay, efficiently and significantly decreased the level of DNA damage induced with H2O2, visible light-excited methylene blue and DMNQ.