Oxidative stress in Saccharomyces cerevisiae is caused by partially reduced forms of molecular oxygen, known as reactive oxygen species (ROS) – e.g. superoxide (O2radical dot−/HO2radical dot), hydrogen peroxide (H2O2), hydroxyl radical (OHradical dot), organic (lipid, alkyl, or short chain) hydroperoxides and peroxyl radicals (ROOradical dot) – that are highly reactive and able of damaging cellular constituents such as lipids ( Manon, 2004) DNA and proteins