Copper-ascorbate reactive oxygen species-generating system (Cu/Asc system)

The copper-ascorbate reactive oxygen species (ROS)-generating system is a chemical redox assembly used primarily in pro-oxidant therapeutic strategies, particularly for cancer treatment (Halliwell & Gutteridge, 1990). It relies on the ability of ascorbic acid (Vitamin C) to act as a reducing agent for copper ions, cycling them between Cu(II) and Cu(I) states (Valko et al., 2005). This cycling facilitates the production of potent ROS, such as hydroxyl radicals, via Fenton-like chemistry, which can overwhelm the antioxidant defenses of target cells, leading to DNA damage and apoptosis (Rowley & Halliwell, 1983). While not a single biological molecule, this system is studied for its ability to selectively target cancer cells, which often exhibit higher baseline oxidative stress and altered metal metabolism (Parrow et al., 2013). Drugs interacting with this system typically include copper chelators or supplements and high-dose ascorbate formulations designed to maximize localized ROS production. The system's efficacy is highly dependent on the local concentration of metal ions and the presence of oxygen or hydrogen peroxide (Uetrecht, 2007).

Other names

Copper-ascorbate redox systemCu(II)/ascorbate systemAscorbate-mediated copper reduction systemCatalytic copper-ascorbate system

The system operates through a cyclic redox process where ascorbate reduces Cu(II) to Cu(I). The resulting Cu(I) reacts with molecular oxygen or endogenous hydrogen peroxide (Fenton-like reaction) to generate highly reactive hydroxyl radicals (.OH) and superoxide anions (O2.-), which induce lethal oxidative damage to cellular components (Halliwell & Gutteridge, 1990; Valko et al., 2005).