Isoprostanes are a class of compounds that are formed by the free radical-catalyzed peroxidation of arachidonic acid, an abundant polyunsaturated fatty acid found in cell membranes. Unlike prostaglandins, which are produced enzymatically, isoprostanes are non-enzymatic products. They are considered reliable markers of oxidative stress and lipid peroxidation, which are critical in understanding cellular damage mechanisms in toxicology.
