Antioxidant Protection from UV- and Light-Stress Related to Carotenoid Structures

Abstract

This review summarizes studies of protection against singlet oxygen and radical damage by carotenoids. The main focus is on how substitutions of the carotenoid molecules determine high antioxidant activities such as singlet oxygen quenching and radical scavenging. Applied assays were carried out either in vitro in solvents or with liposomes, and in a few cases with living organisms. In the latter, protection by carotenoids especially of photosynthesis against light- and UV-stress is of major importance, but also heterotrophic organisms suffer from high light and UV exposure which can be alleviated by carotenoids. Carotenoids to be compared include C30, C40 and C50 molecules either acyclic, monocyclic or bicyclic with different substitutions including sugar and fatty acid moieties. Although some studies are difficult to compare, there is a tendency towards mono and bicyclic carotenoids with keto groups at C-4/C-4’ and the longest possible polyene structure functions to act best in singlet oxygen quenching and radical scavenging. Size of the carotenoid and lipophilic substituents such as fatty acids seem to be of minor importance for their activity but hydroxyl groups at an acyclic end and especially glycosylation of these hydroxyl groups enhance carotenoid activity.

Metabolic Responses of Carotenoid and Cordycepin Biosynthetic Pathways in Cordyceps militaris under Light-Programming Exposure through Genome-Wide Transcriptional Analysis

“…However, the previous report demonstrated that the NOD-coding gene ( Cmfhp ) was significantly up-regulated when C. militaris CM01 was treated with light [ 8 ], and the deletion of this gene resulted in enhancing nitric oxide (NO) content and lowering carotenoid content as compared with the wild type. Possibly, the down-regulation of the NOD gene found in our study might indicate the presence of a compensatory mechanism through the function of photo-protective pigment [ 42 ] to cope with the stress response or, in turn, that the light-programming condition did not largely induce the light stress, and the cell acclimatization occurred in contrast to the effect of the light exposure, as previously studied [ 8 ].…”

Antioxidants in Sport Sarcopenia

“…They evaluated the role of carotenoids in human chronic diseases characterized by oxidative stress, and reported that the beneficial health effects of carotenoids shown in small-scale studies and in subjects suffering from chronic oxidative stress are not evident in large-scale trials with carotenoid supplements. Finally, as recently evidenced by Sandmann et al [127], carotenoids can play a role as direct antioxidants, by quenching singlet oxygen and peroxide radicals.…”

Photoprotection and Skin Pigmentation: Melanin-Related Molecules and Some Other New Agents Obtained from Natural Sources

“…However, all antioxidants are not equivalent. Carotenoid action is based on absorption of UV light and quenching of singlet oxygen [60], polyphenols join light absorption with quenching ROS, and tocopherols are a family of antioxidant molecules especially effective in preventing cell membrane oxidation [61]. Antioxidants such as ascorbate do not have π-electrons and can be easily and rapidly oxidized by atmospheric oxygen, thus losing its efficacy as a photoprotector.…”