Reactive oxygen species and nitric oxide (ROS/NO)

Reactive oxygen species (ROS) and nitric oxide (NO) are a group of highly reactive, oxygen- and nitrogen-containing molecules that serve as critical regulators of cellular physiology [Sies et al., 2017]. In healthy tissues, they function as secondary messengers in signal transduction pathways, regulating processes such as vasodilation, immune response, and gene expression [StatPearls, 2023]. However, an imbalance between their production and the body's antioxidant defenses leads to oxidative and nitrosative stress, which causes damage to DNA, proteins, and lipids [Pizzino et al., 2017]. This damage is a hallmark of various pathologies, including cardiovascular diseases, neurodegeneration, and cancer. Therapeutic strategies involve the use of antioxidants and scavengers to neutralize excess ROS/NO or the use of donors to restore signaling in conditions like endothelial dysfunction [PubChem]. Because these molecules are ubiquitous and essential for normal function, pharmacological intervention requires precise targeting to avoid disrupting homeostatic signaling.

Other names

Reactive oxygen and nitrogen speciesRONSOxidantsFree radicalsReactive oxygen intermediates

Drugs targeting these species typically act as scavengers to neutralize reactive intermediates, as donors to supplement levels (e.g., NO donors), or as inhibitors of the enzymes responsible for their production (e.g., NADPH oxidase or Nitric oxide synthase inhibitors) [Pizzino et al., 2017].