ROS, RNS and RSS

The last decade has seen an upsurge in research into cellular redox processes, from the identification of new reactive species involved in intracellular redox signaling and new redox pathways to diverse dietary and medical interventions. In part, these developments have been fueled by a better understanding of how redox processes control health and disease—and their importance has been augmented by demographic changes in many countries worldwide. Here, an increasingly aging and—oxidatively—stressed population is looking for solutions, from a healthy diet and antioxidants to innovative redox modulating agents and redox control by drugs.

The prime targets of such redox modulators are usually small molecule “reactive species”, such as ROS, RNS, and RSS. Indeed, understanding the biological impact and the underlying chemistry of these reactive, often inorganic species provides a holistic view on redox control. The perspective of oxidants, radicals, stressors, and similar redox signaling molecules essential for the proper functioning of cells and organisms is often eclipsed by their more prominent antioxidant counterparts. Still, there is no “dark side” in redox control: Reactive species and antioxidants belong together, and one without the other would be futile. It is therefore essential to investigate the formation, presence, impact, and also foot- and fingerprints of such oxidizing species in diverse organisms, where ROS, RNS, and RSS are often considered as advantageous. Their roles in strengthening the immune system and fighting human diseases, for instance, is only just being established and other, similar beneficial actions may also be assigned to them.

At the same time, new classes of reactive species are knocking on the door of biological redox control, from reactive chlorine species to reactive selenium species. In fact, redox is not just red and an ox, it is considerably more colorful element-wise and, from the perspective of research, certainly no castrated bull. Quite the contrary, these new species are ushering in a glorious decade of highly multidisciplinary chemical, biochemical, biological, nutritional, and medical redox research. This field is wide open, and the distinct smell of bleach should not prevent us from sniffing around in other parts of the Periodic Table, as iodic or idiotic is may seem at first. RSS were overlooked for decades, and so others could be stowed away under letters such as C, P, Si or Br.

So welcome to the oxidizing side of the redox rocker, where redox really rocks!