Interactions of dietary carotenoids with activated (singlet) oxygen and free radicals: Potential effects for human health

Abstract

Molecular mechanisms associated with the anti-/pro-oxidative properties of carotenoids (CARs) are described in organic solvents, micro-heterogeneous environments and model lipid membranes and in cellular suspensions. Singlet oxygen is important in the skin and eye and CARs are efficient singlet oxygen (SO) quenchers with corresponding rate constants near diffusion controlled (typically app. 10¹⁰ M⁻¹ s⁻¹) with lycopene (LYC) exhibiting the most efficient quenching in organic solvents. However, in membrane environments there is little or no difference in the quenching efficiency between the dietary CARs. Furthermore, aggregation of CARs, particularly those in the macula (lutein and zeaxanthin), markedly reduces SO quenching efficiency. Free radical interactions with CARs leads to at least three processes, electron and hydrogen atom transfer and adduct formation. The most studied is electron transfer where the CAR loses an electron to become a radical cation. The reactivity/lifetime of such CAR radicals may lead to a switch from anti- to pro-oxidant behaviour of CARs. These reactions are related to CAR redox potentials with LYC being the lowest (most easily oxidised) allowing LYC to reduce/repair all other CAR radical cations and LYC 'sacrificed' where mixtures of CARs are present in oxidative environments. Such redox-controlled reactions may lead to deleterious as well as beneficial health effects.

Efeito da Astrocaryum aculeatum (Tucumã) na toxicidade da Doxorrubicina: modelo experimental in vivo

“…(19)(20)(21)23) The antimicrobial properties of the tucumã are reported by Jobim et al (21) These antimicrobial effects of the fruit are associated with its chemical composition, which includes several types of polyphenols. According to Daglia, (22) polyphenols are secondary metabolites produced by superior plants that have antibacterial, antiviral and antifungal properties.…”

Hen egg carotenoids (lutein and zeaxanthin) and nutritional impacts on human health: a review

“…Recently, a review article appeared in print thoroughly discussed the role of egg yolk carotenoids as an antioxidants exerting protective effects against oxidative damage . Molecular mechanisms are involved in the singlet oxygen and radical scavenging activity of lutein and zeaxanthin and as such exert beneficial effects in terms of decreasing or slowing down the light-induced oxidative stress in eye macular or AMD (Böhm, Edge, & Truscott, 2012;Krinsky, Landrum, & Bone, 2003;Li, Ahmed, & Bernstein, 2010). The predominant carotenoid in the fovea of the retina, zeaxanthin, scavenged hydroxyl radicals more effectively than the other retinal carotenoid, lutein (Trevithick-Sutton, Foote, Collins, & Trevithick, 2006).…”

Antioxidant Vitamins as Oxidative Stress Markers in Rat Plasma After Physical Exercise - a Short Report

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