DSBs measured after treatment with different concentrations of ME and EO of Origanum vulgare spp. hirtum. Mean data are from three independent experiments. Error bars represent standard errors of mean values. Where no error bars are evident, errors are equal to or smaller than the symbols. The statistical significance of the differences is presented as follows: * p < 0.05; ** p < 0.01; *** p < 0.001; ns – no significant difference.