Dual stressor effects of lipid oxidation and antioxidants

Abstract Stress is considered as nonspecific response of an organism to stressors (Selye, 1936). “Oxidative stress” was defined in 1985 by Sies as “a disturbance in the prooxidant-antioxidant balance in favor of the former” (Sies, 1985), and at that time, it was considered to play a causative role in the pathogenesis of various disorders and diseases. The definition was updated to include the role in redox signaling:” an imbalance between oxidants and antioxidants in favor of the oxidants, leading to a disruption of redox signaling and control and/or molecular damage” (Sies & Jones, 2007). Oxidative stress was originally assumed to be harmful, but now, it is known that reactive oxygen species (ROS) and related reactive species play an important role in the host defense and production of biologically essential substances and also act in physiological settings as redox signaling messenger with important regulatory functions (Holmstrom and Finkel, 2014). Oxidative stress is considered as a signal or stimulus that affects redox balance and induces oxidation reaction of biological molecules, resulting in either maintenance of homeostasis (positive eustress) or induction of deleterious damage (negative distress) (Niki, 2009; Niki, 2016). Oxidative distress and eustress have received considerable attention recently (Niki, 2016; Sies, 2017; Sies et al., 2017).