Oxidation products of astaxanthin: An overview

Abstract It was reported that the mechanism whereby carotenoids such as astaxanthin scavenge singlet oxygen was a physical reaction. Namely, carotenoids take up thermal energy from singlet oxygen and release this energy by polyene vibration. Recent investigations revealed that carotenoids could scavenge reactive oxygen species through chemical reactions. A series of apoastaxanthins were obtained as out-oxidation products of astaxanthin. These compounds were considered to take up oxygen by polyene in astaxanthin. Astaxanthin epoxides were produced by reaction of astaxanthin with hydroxyl radical and superoxide anion radical. Similarly, astaxanthin endperoxides were formed by astaxanthin with the reaction of singlet oxygen. Furthermore, astaxanthin forms nitroastaxanthins by the reaction of peroxynitrite. These results indicate that astaxanthin is able to capture reactive oxygen and nitrogen species by its molecules.