Reactive oxygen species scavenging properties of newly synthesised nitrogen compounds

Several pathologies result from an excessive intracellular production of reactive oxygen species (ROS). So, the search for new substances that can act against them, beyond the cells natural defences, has been increasing in the last few years. In this study we used new nitrogen compounds, from organic synthesis, to evaluate their real capacity as ROS scavengers. The new compounds were screened for their citotoxicity using LDH release test, in L929 cell line. The non-toxic ones were subsequently evaluated for their antiradical activity, determined by the DPPH discoloration method. Some of them presented an antiradical activity far superior to the traditional antioxidants a-tocopherol and trolox. At the IC50 concentration previously determined by the DPPH reduction test, the compounds revealed also as very effective in scavenging hydroxyl radicals, assessed by the 2-deoxy-D-ribose degradation assay. We selected the compounds with better overall performance and used them to monitor their protective effect on intracellular ROS formation in a PC12 cell model. The results obtained by flow cytometry, using the fluorescent probe H2DCF-DA, show that the compounds succeeded in preventing intracellular ROS formation induced by the oxidant pair ascorbate/iron. Altogether, these data are indicative of a quite good antioxidant potential for the new compounds that encourages complementar investigation.FCT grants SFRH/BD/17174/2004 and SFRH/BD/3185/200