4-hydroxy Nonenal (4-HNE; Item No. 32100) is a lipid peroxidation product derived from oxidized ?-6 polyunsaturated fatty acids, such as linoleic acid and arachidonic acid, that is widely used as a marker of oxidative stress.{869,1103} 4-HNE exhibits various biological activities such as cytotoxicity, growth inhibiting activity, genotoxicity, and chemotactic activity.{869,1103,1109} 4-hydroperoxy 2-Nonenal is the immediate precursor of 4-HNE formed from the cleavage of ?-6 hydroperoxides.{10101} Analogous reactions are expected to occur with hydroperoxides from other ?-6 fatty acids, particularly arachidonic acid.