AbstractÐFor a safety evaluation of foodstu derived from genetically modi®ed crops, the concept of the substantial equivalence of modi®ed organisms with their parental lines is used following an environmental safety evaluation. To assess the potential pleiotropic eect of genetic modi®cations on constituents of modi®ed crops data from US and EC documents were investigated with regard to inherent plant toxins and antinutrients. Analysed were documents of rape (glucosinolates, phytate), maize (phytate), tomato (tomatine, solanine, chaconine, lectins, oxalate), potato (solanine, chaconine, protease-inhibitors, phenols) and soybean (protease-inhibitors, lectins, iso¯avones, phytate). In several documents used for noti®cations no declarations even on essential inherent plant toxins and antinutrients could be found, for instance data on phytate in modi®ed maize were provided only in one of four documents. Signi®cant variations in the contents of these compounds in parental and modi®ed plants especially due to environmental in¯uences were observed: drought stress, for example, was made responsible for signi®cantly increased glucosinolate levels of up to 72.6 m mmol/g meal in modi®ed and parental rape plants in ®eld trials compared to recommended standard concentrations of less than 30 m mmol/g. Taking into account these wide natural variations generally the concentrations of inherent plant toxins and antinutrients in modi®ed products were in the range of the concentrations in parental organisms. The results presented indicate that the concept of the substantial equivalence is useful for the risk assessment of genetically modi®ed organisms (GMOs) used for novel foods but possible environmental in¯uences on constituents of modi®ed crops need more attention. Consistent guidelines, specifying data of relevant compounds which have to be provided for noti®cation documents of speci®c organisms have to be established. Because of the importance of inherent plant toxins and antinutrients on nutritional safety, also coherent databases of standard parental lines and clear criteria for mandatory declarations are necessary.
