CAROTENOID PROTECTION AGAINST OXIDATION

Based on experimental observations made in photosynthetic organisms which lacked colored carotenoid pigments, a hypothesis was developed that these pigments could serve as protective agents against photosensitized oxidations. Over the last 20 years, many workers have confirmed this hypothesis and have extended the observations to non-photosynthetic bacteria, plants and animals. It has also been possible to demonstrate carotenoid protection in in vitro systems. This article reviews the major mechanisms whereby carotenoid pigments protect cells against harmful photosensitized oxidations. The mechanisms include: (1) Carotenoid quenching of triplet sensitizers. (2) Carotenoid quenching of O2 1g). (3) Carotenoid inhibition of free radical reactions. © 1979, Walter de Gruyter. All rights reserved.