ABSTRACT
Carotenoids are biosynthesized by plants, algae, fungi, and bacteria (1,2). In these organisms they appear to play a number of roles, especially light-harvesting in plants and protecting cells from oxidative damage. A number of carotenoids, such as βcarotene, astaxanthin, and lycopene, are good antioxidants in lipid phases and function as free radical scavengers or singlet oxygen quenchers (3). Singlet oxygen (1O2) is known to damage DNA and to be mutagenic. Carotenoids act by absorbing the energy of the singlet oxygen onto the carotenoid chain; this leads to the degradation of the carotenoid molecule, but it prevents other molecules or tissues from being damaged. Carotenoids can also prevent the chain reaction production of free radicals initiated by the degradation of polyunsaturated fatty acids and thus prevents accelerated degradation of lipid membranes. It is these corotenoid properties that are used to explain epidemiological and experimental studies indicating that dietary carotenoids inhibit the onset of a range of diseases, such as cataracts, age-related macular degeneration, multiple sclerosis, arteriosclerosis, and some cancers (4-7).
