The interaction of carotenoids with reactive oxy-species

Abstract

The reactivity of carotenoids with ROS including singlet oxygen (102), superoxide radical anions (02.-and cc1302.) is reported. The effects of environment are marked, thus while lycopene reacts with 1 0 2 somewhat faster ( 1 . 6~) than pcarotene in simple solvents the trend is reversed in micellar systems (0.3~). In fact, for the twelve carotenoids studied in detergents, the reactivity depends mainly on the size of the carotenoid. In cellular systems the highest protection of the cell from photo-oxidative damage was given by lycopene followed by astaxanthin then p-carotene with only a small protection by canthaxanthin. All twelve carotenoids studied react efficiently with 1 0 2 (k=1-20 x 109 M-1s-1) in simple solvents and micelles while the reactivity with oxy-radicals is quite different. Thus, for example, &carotene reacts with 02.-to form an addition complex whereas with lycopene reversible electron transfer is observed.Consistent with such marked differences pcarotene--readily transfers an electron to lycopene. Carotenoids also react with the oxy-radical from carbon tetrachloride (cc1302.) to yield radical cations plus another product which may be an addition complex analogous to that produced with 02.-.Abbreviations used : Reactive oxy-species = ROS

α-Tocopherol increases caspase-3 up-regulation and apoptosis by β-carotene cleavage products in human neutrophils

“…It has been suggested that the detrimental effect of carotenoids is due to the prooxidative properties of βcarotene and of its oxidation products [8,9]. The formation of carotenoid radical cations has been regarded as an intermediate step in the reaction cascade triggered by peroxyl radicals that are produced by the cells and damage the cell structures [22,23]. A relationship between apoptosis induction and changes of intracellular redox potential has been observed in human adenocarcinoma cells [24].…”

Improving Asthma during Pregnancy with Dietary Antioxidants: The Current Evidence

“…Twenty four carotenoids have been reported to provide health benefits due to their antioxidant properties [90]. In particular, lycopene and β-carotene have been shown to scavenge ROS [91,92]. An increase in dietary antioxidants may improve asthma during pregnancy, however, further studies are required.…”