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Black HS, Boehm F, Edge R, Truscott TG. The Benefits and Risks of Certain Dietary Carotenoids that Exhibit both Anti- and Pro-Oxidative Mechanisms-A Comprehensive Review. Antioxidants (Basel) 2020; 9:E264. [PMID: 32210038 PMCID: PMC7139534 DOI: 10.3390/antiox9030264] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 01/04/2023] Open
Abstract
Carotenoid pigments, particularly β-carotene and lycopene, are consumed in human foodstuffs and play a vital role in maintaining health. β-carotene is known to quench singlet oxygen and can have strong antioxidant activity. As such, it was proposed that β-carotene might reduce the risk of cancer. Epidemiological studies found inverse relationships between cancer risk and β-carotene intake or blood levels. However, clinical trials failed to support those findings and β-carotene supplementation actually increased lung cancer incidence in male smokers. Early experimental animal studies found dietary β-carotene inhibited UV-induced skin cancers. Later studies found that β-carotene supplementation exacerbated UV-carcinogenic expression. The discrepancies of these results were related to the type of diet the animals consumed. Lycopene has been associated with reduced risk of lethal stage prostate cancer. Other carotenoids, e.g., lutein and zeaxanthin, play a vital role in visual health. Numerous studies of molecular mechanisms to explain the carotenoids' mode of action have centered on singlet oxygen, as well as radical reactions. In cellular systems, singlet oxygen quenching by carotenoids has been reported but is more complex than in organic solvents. In dietary β-carotene supplement studies, damaging pro-oxidant reactivity can also arise. Reasons for this switch are likely due to the properties of the carotenoid radicals themselves. Understanding singlet oxygen reactions and the anti-/pro-oxidant roles of carotenoids are of importance to photosynthesis, vision and cancer.
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Affiliation(s)
- Homer S. Black
- Department of Dermatology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Fritz Boehm
- Photobiology Research, Internationales Handelszentrum (IHZ), Friedrichstraße 95, 10117 Berlin, Germany;
| | - Ruth Edge
- Dalton Cumbrian Facility, Westlakes Science Park, The University of Manchester, Cumbria CA24 3HA, UK
| | - T. George Truscott
- School of Chemical and Physical Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK;
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Edge R, Truscott TG. Singlet Oxygen and Free Radical Reactions of Retinoids and Carotenoids-A Review. Antioxidants (Basel) 2018; 7:antiox7010005. [PMID: 29301252 PMCID: PMC5789315 DOI: 10.3390/antiox7010005] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 12/11/2017] [Accepted: 12/29/2017] [Indexed: 12/29/2022] Open
Abstract
We report on studies of reactions of singlet oxygen with carotenoids and retinoids and a range of free radical studies on carotenoids and retinoids with emphasis on recent work, dietary carotenoids and the role of oxygen in biological processes. Many previous reviews are cited and updated together with new data not previously reviewed. The review does not deal with computational studies but the emphasis is on laboratory-based results. We contrast the ease of study of both singlet oxygen and polyene radical cations compared to neutral radicals. Of particular interest is the switch from anti- to pro-oxidant behavior of a carotenoid with change of oxygen concentration: results for lycopene in a cellular model system show total protection of the human cells studied at zero oxygen concentration, but zero protection at 100% oxygen concentration.
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Affiliation(s)
- Ruth Edge
- Dalton Cumbrian Facility, The University of Manchester, Westlakes Science and Technology Park, Moor Row, Cumbria CA24 3HA, UK.
| | - T George Truscott
- School of Chemical and Physical Sciences, Lennard-Jones Building, Keele University, Staffordshire ST5 5BG, UK.
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Black HS. Reassessment of a Free Radical Theory of Cancer With Emphasis on Ultraviolet Carcinogenesis. Integr Cancer Ther 2016; 3:279-93. [PMID: 15523099 DOI: 10.1177/1534735404270612] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Pro-oxidants, reactive species and free radicals, are toxic substances that can cause oxidative damage to major constituents of biological systems. In contradistinction, antioxidants are defined as any substance that significantly prevents the pro-oxidant-initiated oxidation of a substrate. Consequently, it was suggested that it might be possible to reduce free radical damage and thus cancer risk through 3 dietary changes: (1) caloric reduction, that is, lowering the level of free radical reactions arising in the course of normal metabolism; (2) minimize dietary components that increase the level of free radical reactions (eg, polyunsaturated fats); and (3) supplement the diet with one or more free radical reaction inhibitors (antioxidants). Lipid peroxidation exemplifies the type of chain reaction initiated by free radicals in (2) and (3). Both the phenolic antioxidant butylated hydroxytoluene (BHT) and the carotenoid β-carotene can terminate such reactions and have been shown to influence ultraviolet (UV) carcinogenesis. However, there is a lack of correlation between physicochemical and patho-physiological responses in both instances. Whereas the influence on UV carcinogenesis of both antioxidants has been reported to diminish as the level of dietary fat decreases, pointing to the involvement of lipid peroxidative reactions, the mode of BHT’s action in inhibiting UV carcinogenesis appears to be related to UV dose diminution through increased spectral absorbance of the stratum corneum. β-carotene has no such effect and may actually exacerbate UV carcinogenesis under certain dietary conditions. This paradox points to the complex relationship between chemical mechanisms and biological mode of action of antioxidants. Recent clinical and experimental data suggest that antioxidant supplementation of the complex and intricately balanced natural antioxidant defense system as a cancer prevention strategy will demand extreme caution.
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Affiliation(s)
- Homer S Black
- Department of Dermatology, Baylor College of Medicine, Houston, Texas, USA.
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Boehm F, Edge R, Truscott TG, Witt C. A dramatic effect of oxygen on protection of human cells against γ-radiation by lycopene. FEBS Lett 2016; 590:1086-93. [PMID: 26991327 DOI: 10.1002/1873-3468.12134] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 02/24/2016] [Accepted: 02/29/2016] [Indexed: 12/24/2022]
Abstract
Reducing radiation damage is important and dietary antioxidants that can protect cells from such damage are of value. Dietary lycopene, a carotenoid found in tomatoes, protects human lymphoid cell membranes from damage by γ-radiation. We report that such protective effects are remarkably reduced as the oxygen concentration increases - near zero at 100% oxygen from fivefold protection at 20% oxygen and, dramatically, from 50-fold protection at 0% oxygen. Such huge differences imply that under higher oxygen concentrations lycopene could lead to improved cancer therapy using γ-radiation. The cells are not efficiently protected from the superoxide radical by lycopene. Noncellular studies suggest molecular mechanisms for the oxygen effect.
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Affiliation(s)
| | - Ruth Edge
- Dalton Cumbrian Facility, Westlakes Science & Technology Park, The University of Manchester, Cumbria, UK
| | - Terence George Truscott
- School of Physical and Geographical Sciences (Chemistry Section), Keele University, Staffordshire, UK
| | - Christian Witt
- Department of Pneumonology, Charité Hospital, University Medicine, Berlin, Germany
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El-Agamey A, McGarvey DJ. Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor. Free Radic Biol Med 2016; 90:75-84. [PMID: 26549878 DOI: 10.1016/j.freeradbiomed.2015.10.427] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/10/2015] [Accepted: 10/26/2015] [Indexed: 11/15/2022]
Abstract
The reactions of acetylperoxyl radicals with different carotenoids (7,7'-dihydro-β-carotene and ζ-carotene) in SDS and CTAC microemulsions of different compositions were investigated using laser flash photolysis (LFP) coupled with kinetic absorption spectroscopy. The primary objective of this study was to explore the influence of microemulsion composition and the type of surfactant used on the yields and kinetics of various transients formed from the reaction of acetylperoxyl radicals with carotenoids. Also, the influence of the site (hydrocarbon phases or aqueous phase) of generation of the peroxyl radical precursor was examined by using 4-acetyl-4-phenylpiperidine hydrochloride (APPHCl) and 1,1-diphenylacetone (11DPA) as water-soluble and lipid-soluble peroxyl radical precursors, respectively. LFP of peroxyl radical precursors with 7,7'-dihydro-β-carotene (77DH) in different microemulsions gives rise to the formation of three distinct transients namely addition radical (λmax=460 nm), near infrared transient1 (NIR, λmax=700 nm) and 7,7'-dihydro-β-carotene radical cation (77DH(•+), λmax=770 nm). In addition, for ζ-carotene (ZETA) two transients (near infrared transient1 (NIR1, λmax=660 nm) and ζ-carotene radical cation (ZETA(•+), λmax=730-740 nm)) are generated following LFP of peroxyl radical precursors in the presence of ζ-carotene (ZETA) in different microemulsions. The results show that the composition of the microemulsion strongly influences the observed yield and kinetics of the transients formed from the reactions of peroxyl radicals (acetylperoxyl radicals) with carotenoids (77DH and ZETA). Also, the type of surfactant used in the microemulsions influences the yield of the transients formed. The dependence of the transient yields and kinetics on microemulsion composition (or the type of surfactant used in the microemulsion) can be attributed to the change of the polarity of the microenvironment of the carotenoid. Furthermore, the nature of the peroxyl radical precursor used (water-soluble or lipid-soluble peroxyl radical precursors) has little influence on the yields and kinetics of the transients formed from the reaction of peroxyl radicals with carotenoids. In the context of the interest in carotenoids as radical scavenging antioxidants, the fates of the addition radicals (formed from the reaction of carotenoid with peroxyl radicals) and carotenoid radical cations are discussed.
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Affiliation(s)
- Ali El-Agamey
- School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK; Chemistry Department, Faculty of Science, Damietta University, New Damietta, Damietta, Egypt.
| | - David J McGarvey
- School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK
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Zaidi A, Li H, Sliwka HR, Partali V, Ernst H, Melø TB. Energy and electron transfer reactions of polyenic acids with variable chain lengths. Tetrahedron 2013. [DOI: 10.1016/j.tet.2012.10.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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BERNARDI BFERNANDO, GARAVELLI MARCO, OLUCCI MASSIMO. Trans cis isomerization in long linear polyenes as beta-carotene models: a comparative CAS-PT2 and DFT study. Mol Phys 2010. [DOI: 10.1080/002689797170095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Lichens – Photophysical studies of potential new sunscreens. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2009; 95:40-5. [DOI: 10.1016/j.jphotobiol.2008.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 11/24/2008] [Accepted: 12/16/2008] [Indexed: 11/24/2022]
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Naqvi KR, Melø TB, Jávorfi T, González-Pérez S, Arellano JB. Facile method for spectroscopic examination of radical ions of hydrophilic carotenoids. Phys Chem Chem Phys 2009; 11:6401-5. [DOI: 10.1039/b905454e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kildahl-Andersen G, Konovalova TA, Focsan AL, Kispert LD, Anthonsen T, Liaaen-Jensen S. Comparative studies on radical cation formation from carotenoids and retinoids. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.09.088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sliwka HR, Melø TB, Foss BJ, Abdel-Hafez SH, Partali V, Nadolski G, Jackson H, Lockwood SF. Electron- and energy-transfer properties of hydrophilic carotenoids. Chemistry 2007; 13:4458-66. [PMID: 17340673 DOI: 10.1002/chem.200601527] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The antioxidant activities-expressed as the electron-donating properties-of five hydrophilic carotenoids (carotenoid surfactants) and three related hydrophobic carotenoids were investigated by flash photolysis. The electron-transfer rates of the carotenoids to the triplet state of the sensitizer 2-nitronaphthalene and the energy transfer rates of triplet 2-nitronaphthalene to the carotenoids were determined. The results demonstrate that the electron-donating effects of the hydrophilic and hydrophobic carotenoids were comparable when evaluated in acetonitrile. In the presence of water, however, electron transfer (i.e., antioxidant efficiency) was enhanced by a factor of four for the hydrophilic carotenoids. The increased hydrophilicity of carotenoids, therefore, could expand their antioxidant properties, thus facilitating their use as aqueous-phase radical scavengers. At the same time, it was shown that supramolecular assembly ("aggregation") of the amphiphilic carotenoids prevented electron transfer, thus deactivating the antioxidant function. Modulation of the biophysical properties of carotenoids through synthetic modification is capable of increasing the biological and medical utility of this natural class of predominantly hydrophobic antioxidant compound.
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Affiliation(s)
- Hans-Richard Sliwka
- Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
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Abstract
The possibility that carotenoid radicals react with oxygen to form chain-carrying peroxyl radicals has been postulated to account for the reduction in antioxidant effetiveness displayed by some carotenoids at high oxygen concentrations. The primary objective of the work described in this paper was to measure the rate constants for oxygen addition to a series of carotenoid radicals and to examine any influence of carotenoid structural features on these rate constants. Laser flash photolysis has been used to generate long-lived carotenoid radicals (PhS-CAR radical) derived from radical addition reactions with phenylthiyl radicals (PhS radical) in benzene. The PhS-CAR radical radicals are scavenged by oxygen at rates that display a moderate dependence on the number of conjugated double bonds (ndb) in the carotenoid. The rate constants range from approximately 10(3) to approximately 10(4) M- 1 s- 1 for ndb = 7-11. The data also suggest that the presence of terminal cyclic groups may cause an increase in the rate constant for oxygen addition.
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Affiliation(s)
- Ali El-Agamey
- School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, Staffordshire, UK
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Enes RF, Tomé AC, Cavaleiro JA, El-Agamey A, McGarvey DJ. Synthesis and solvent dependence of the photophysical properties of [60]fullerene–sugar conjugates. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.09.078] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Kombarova SV, Il'ichev YV. Mapping the triplet potential energy surface of 1-methyl-8-nitronaphthalene. J Org Chem 2005; 70:6074-84. [PMID: 16018705 DOI: 10.1021/jo0509253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spin-unrestricted calculations and time-dependent DFT were used to characterize structure and reactivity of 1-methyl-8-nitronaphthalene (1) in the triplet state. Four hybrid models (B3LYP, PBE0, MPW1K, BHLYP) with significantly different amount of the exact exchange were employed. The triplet potential energy surface of 1 was mapped by using the UB3LYP and UMPW1K techniques. Both hybrid models provided qualitatively consistent pictures for the potential energy landscape. Thirty-one stationary points, of which 15 were minima, were found at the UB3LYP level of theory. Three minima corresponding to the nitro form of 1 were located on the triplet surface; just one was found for the singlet ground state. Two reaction paths leading from 1 either to a nitrite-type intermediate (2) or to the aci-form (3) were characterized. For both paths, reaction products were of diradical nature. The lower activation energy was obtained for the triplet-state tautomerization affording 3. The ground state of triplet multiplicity was predicted for two isomers of the aci-form. The triplet diradical 3 is expected to react through the thermal population of a close-lying singlet excited state. The results are discussed in relation to mechanisms of photoinduced rearrangements of peri-substituted nitronaphthalenes that can be used to develop novel photolabile protecting groups.
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Affiliation(s)
- Svetlana V Kombarova
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA
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Photolysis of carotenoids in chloroform: enhanced yields of carotenoid radical cations in the presence of a tryptophan ester. Radiat Phys Chem Oxf Engl 1993 2005. [DOI: 10.1016/j.radphyschem.2003.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Affiliation(s)
- Homer S Black
- Department of Dermatology, Baylor College of Medicine, Houston, TX 77030, USA.
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Black HS. Pro-carcinogenic activity of β-carotene, a putative systemic photoprotectant. Photochem Photobiol Sci 2004; 3:753-8. [PMID: 15295631 DOI: 10.1039/b316438a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Beta-carotene is a strong singlet oxygen quencher and antioxidant. Epidemiologic studies have implied that an above average intake of the carotenoid might reduce cancer risks. Earlier studies found that the carotenoid, when added to commercial closed-formula rodent diets, provided significant photoprotection against UV-carcinogenesis in mice. Clinical intervention trials found that beta-carotene supplementation evoked no change in incidence of nonmelanoma skin cancer. However, when smokers were supplemented with the carotenoid a significant increase in lung cancer resulted. Recently, employing a beta-carotene supplemented semi-defined diet, not only was no photoprotective effect found, but significant exacerbation of UV-carcinogenesis occurred. Earlier, a mechanism, based upon redox potential of interacting antioxidants, was proposed in which beta-carotene participated with vitamins E and C to efficiently repair oxy radicals and, thus, thought to provide photoprotection. In this schema, alpha-tocopherol would first intercept an oxy radical. In terminating the radical-propagating reaction, the tocopherol radical cation is formed which, in turn, is repaired by beta-carotene to form the carotenoid radical cation. This radical is repaired by ascorbic acid (vitamin C). As the carotenoid radical cation is a strongly oxidizing radical, unrepaired it could contribute to the exacerbating effect on UV-carcinogenesis. Thus, vitamin C levels could influence the levels of the pro-oxidant carotenoid radical cation. However, when hairless mice were fed beta-carotene supplemented semi-defined diet with varying levels of vitamin C (0-5590 mg kg(-1) diet) no effect on UV-carcinogenesis was observed. Lowering alpha-tocopherol levels did result in further increase of beta-carotene exacerbation, suggesting beta-carotene and alpha-tocopherol interaction. It was concluded that the non-injurious or protective effect of beta-carotene found in the closed-formula rations might depend on interaction with other dietary factors that are absent in the semi-defined diet. At present, beta-carotene use as a dietary supplement for photoprotection should be approached cautiously.
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Affiliation(s)
- Homer S Black
- Department of Dermatology, Baylor College of Medicine, Houston, Texas, 77030, USA
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Black HS, Gerguis J. Modulation of dietary vitamins E and C fails to ameliorate b-carotene exacerbation of UV carcinogenesis in mice. Nutr Cancer 2003; 45:36-45. [PMID: 12791503 DOI: 10.1207/s15327914nc4501_5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
b-Carotene is a strong singlet oxygen quencher and, under most conditions, exhibits strong antioxidant properties. Based on these properties, and a number of epidemiological studies, it was suggested that an above average intake of the carotenoid might reduce cancer risks. Earlier studies had found that b-carotene, when added to commercial closed-formula rodent diets, provided significant photoprotection to ultraviolet light (UV) carcinogenesis. However, clinical trials found that b-carotene supplementation evoked no change in incidence of nonmelanoma skin cancer and that smokers suffered a significant increase in lung cancer incidence. Further, recent studies, employing b-carotene-supplemented semidefined diets, not only failed to find a photoprotective effect, but significant exacerbation of UV carcinogenic expression resulted. Based on the relative electron transfer rate constants for interactions between b-carotene, a-tocopherol (vitamin E), and vitamin C, a mechanism was proposed for the repair of b-carotene radical cation, a strongly oxidizing radical resulting from b-carotene interactions with many oxidizing species. It was theorized that vitamin C repaired the carotenoid radical cation. As mice have no nutritional requirement for vitamin C and smokers are known to exhibit low levels of the vitamin, it was suggested that differences in the relative levels of vitamin C in closed-formula rations (no vitamin C) in which photoprotection occurred, and semidefined diets (containing vitamin C) in which exacerbation resulted, might account for the differences in response. Hairless mice were fed b-carotene-supplemented semidefined diets containing varying levels of vitamins E and C (either increasing their concentrations or reducing them to reflect levels found in closed-formula rations) and subjected to a UV carcinogenesis protocol. Increasing levels of vitamins E and C did not ameliorate b-carotene exacerbation of UV carcinogenesis. Nor did elimination of vitamin C from the diet. Reduced levels of dietary vitamin E augmented b-carotene exacerbation of UV carcinogenic expression, suggesting vitamin E and b-carotene interaction. It is concluded that the photoprotective effect of b-carotene reported earlier by others, or the noninjurious effect of b-carotene found in our studies with closed-formula rations, might depend on interaction with other dietary factors that are either absent, or present in ineffectual concentrations, in the semidefined diet in which exacerbation of UV carcinogenesis occurs. Those factors could be other carotenoids, their isomers, or some yet unidentified phytochemical(s).
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Affiliation(s)
- Homer S Black
- Veterans Affairs Medical Center and Baylor College of Medicine, Houston, TX 77030, USA
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Naqvi KR, Melø TB, Sliwka HR, Mohamad SBB, Partali V. Photochemical and photophysical behaviour of vitamin E: interaction of its long-lived transient photoproducts with carotenoids. Photochem Photobiol Sci 2003; 2:381-5. [PMID: 12760534 DOI: 10.1039/b210972g] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multi-channel, flash kinetic spectroscopy with microsecond time resolution has been used for investigating the interactions between carotenoids and the following photoproducts of alpha-tocopherol (EH) in hexane, methanol, acetonitrile, and dimethyl sulfoxide: (a) the lowest triplet, (b) the tocopherol radical cation, which could be seen only in the polar aprotic solvents acetonitrile and dimethyl sulfoxide, and (c) the neutral tocopheroxyl radical. The first two species reconvert to EH by transferring triplet excitation and positive charge (respectively) to the carotenoid; the third is unreactive. The relevance of these observations to photoprotection and the photoionisation of sterically hindered phenols is pointed out.
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Affiliation(s)
- K Razi Naqvi
- Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
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Cantrell A, McGarvey DJ, Truscott TG, Rancan F, Böhm F. Singlet oxygen quenching by dietary carotenoids in a model membrane environment. Arch Biochem Biophys 2003; 412:47-54. [PMID: 12646267 DOI: 10.1016/s0003-9861(03)00014-6] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability of several dietary carotenoids to quench singlet oxygen in a model membrane system (unilamellar DPPC liposomes) has been investigated. Singlet oxygen was generated in both the aqueous and the lipid phase, with quenching by a particular carotenoid independent of the site of generation. However, singlet oxygen quenching is dependent on the carotenoid incorporated; xanthophylls exhibit a marked reduction in efficiency compared to the hydrocarbon carotenoids. Lycopene and beta-carotene exhibit the fastest singlet oxygen quenching rate constants (2.3-2.5 x 10(9)M(-1)s(-1)) with lutein the least efficient (1.1 x 10(8)M(-1)s(-1)). The other carotenoids, astaxanthin and canthaxanthin, are intermediate. Zeaxanthin exhibits anomalous behavior, and singlet oxygen quenching decreases with increasing amounts of zeaxanthin, leading to nonlinear plots for the decay of singlet oxygen with zeaxanthin concentration. Such differences are discussed in terms of carotenoid structure and their influence on the properties of the lipid membrane. The formation of aggregates by the polar carotenoids is also proposed to be of significance in their ability to quench singlet oxygen.
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Affiliation(s)
- Ann Cantrell
- School of Chemistry and Physics, Lennard-Jones Laboratories, Keele University, Staffordshire, ST5 5BG, UK
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El-Agamey A, McGarvey DJ. Evidence for a lack of reactivity of carotenoid addition radicals towards oxygen: a laser flash photolysis study of the reactions of carotenoids with acylperoxyl radicals in polar and non-polar solvents. J Am Chem Soc 2003; 125:3330-40. [PMID: 12630889 DOI: 10.1021/ja027986s] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we report the results of a laser flash photolysis study of the reactions of a range of carotenoids with acylperoxyl radicals in polar and nonpolar solvents. The results show, for the first time, that carotenoid addition radicals do not react with oxygen to form carotenoid peroxyl radicals; an observation which is of significance in relation to antioxidant/pro-oxidant properties of carotenoids. Acylperoxyl radicals, generated by photolysis of ketone precursors in oxygenated solvents, display high reactivity toward carotenoids in both polar and nonpolar solvents, but the nature of the carotenoid radicals formed is dependent on solvent polarity. In hexane, acylperoxyl radicals react with carotenoids with rate constants in the region of 10(9) M(-1) s(-1) and give rise to transient absorption changes in the visible region that are attributed to the formation of addition radicals. All of the carotenoids show bleaching in the region of ground-state absorption and, with the exception of 7,7'-dihydro-beta-carotene (77DH), no distinct absorption features due to addition radicals are observed beyond the ground state absorption region. For 77DH, the addition radical displays an absorption band that is spectrally resolved from the parent carotenoid absorption. The rate of decay of the 77DH addition radical is unaffected by oxygen in the concentration range 10(-4)-10(-2) M, suggesting that these resonance-stabilized carbon-centered radicals are not scavenged by oxygen. At low incident laser intensities, the 77DH addition radical decay kinetics are 1st order with k(1) approximately 4 x 10(3) s(-1) at room temperature. The 1st order decay is attributed to an intramolecular cyclization process, which is supported by the substantial negative entropies of activation obtained from measurements of the decay rate constants for different 77DH addition radicals as a function of temperature. No transient absorption features are observed in the red or near-infrared regions in hexane for any of the carotenoids studied. In polar solvents such as methanol, acylperoxyl radicals also react with carotenoids with rate constants in the region of 10(9) M(-1) s(-1), but give rise to transient absorption changes in both the visible and the red/near-infrared regions, where it is evident that there are two distinct species. For 77DH, the addition radical absorption around 450 nm is still evident, although its kinetic behavior differs from its behavior in hexane. For 77DH and zeta-carotene (zeta-CAR) the spectral and kinetic resolution of the various absorption bands simplifies kinetic analysis. The kinetic evidence suggests that addition radical formation precedes formation of the two near-infrared absorbing species, and that the kinetics of the addition radical decay match the kinetics of formation of the first of these species (NIR1, absorbing at shorter wavelengths). The decay of NIR1 leads to NIR2, which is attributed to the carotenoid radical cation. The solvent dielectric constant dependence of the relative amounts of NIR1 and NIR2 formed leads us to speculate that NIR1 is an ion-pair. However, an alternative assignment for NIR1 is an isomer of the radical cation. The results, in terms of the pattern of reactivity the carotenoids display and of the properties of the carotenoid radicals formed, are discussed in relation to the antioxidant/pro-oxidant properties of carotenoids.
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Affiliation(s)
- Ali El-Agamey
- Lennard-Jones Laboratories, School of Chemistry and Physics, Keele University, Keele, Staffs ST5 5BG, United Kingdom
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24
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Polyakov NE, Kruppa AI, Bashurova VS, Leshina TV, Kispert LD. The role of radicals in the phototransformations of β-ionone in the presence of electron donors in solution. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00267-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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25
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POLYAKOV NE, LESHINA TV. The influence of electron donors and acceptors on the isomer distribution in the photolysis of β-ionone. Mol Phys 2002. [DOI: 10.1080/00268970110109844] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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26
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Böhm F, Edge R, Burke M, Truscott TG. Dietary uptake of lycopene protects human cells from singlet oxygen and nitrogen dioxide - ROS components from cigarette smoke. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 64:176-8. [PMID: 11744404 DOI: 10.1016/s1011-1344(01)00221-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
There is current interest in the health benefits of dietary carotenoids and the possible deleterious effects on certain sub-populations such as smokers. Here we report in vivo protection of human lymphocytes, conferred by dietary supplementation of lycopene rich foods against the reactive oxygen species, NO(2)(*) radical (by electron transfer) and 1(O)(2) (by energy transfer). It was found that a lycopene rich diet, maintained for 14 days, increased the serum lycopene level 10 fold compared to serum obtained after the same period, where a typical western European diet had been consumed. Relative lymphocyte protection factors of 17.6 and 6.3 against NO(2)(*) radical and 1(O)(2), respectively, were obtained, which re-enforce epidemiological data, showing protection against several chronic diseases by tomato lycopene.
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Affiliation(s)
- F Böhm
- Meclinic Berlin, Friedrichstrasse 71, 10117 Berlin, Germany.
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27
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Cantrell A, McGarvey DJ, Roberts J, Sarna T, Truscott TG. Photochemical studies of A2-E. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 64:162-5. [PMID: 11744402 DOI: 10.1016/s1011-1344(01)00224-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Lipofuscin is thought to be involved in age-related macular degeneration as is one of its proposed components, an amphiphillic pyridinium-based bis-retinoid with a quaternary nitrogen atom, known as A2-E. We report the triplet state spectra obtained from photosensitisation using anthracene and 1-nitronaphthalene in benzene and methanol. The triplet state of A2-E has lambda(max) at 550 nm and a lifetime of approximately 30 micros, it is efficiently quenched by molecular oxygen with a second-order quenching rate constant of approximately 1 x 10(9) dm(3) mol(-1) s(-1). There is no significant triplet state formation from direct laser excitation of A2-E and hence its quantum yield of triplet state formation must be <0.01.
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Affiliation(s)
- A Cantrell
- School of Chemistry and Physics, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG, UK.
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28
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Cantrell A, McGarvey DJ. Photochemical studies of 4-tert-butyl-4'-methoxydibenzoylmethane (BM-DBM). JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 64:117-22. [PMID: 11744398 DOI: 10.1016/s1011-1344(01)00226-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Kinetic UV-VIS absorption data following 355 and 266 nm nanosecond laser flash photolysis of 4-tert-butyl-4'-methoxydibenzoylmethane (BM-DBM) solutions is presented. The kinetics of the decay of the non-chelated enol (NCE) produced following 355 nm excitation of BM-DBM solutions are analysed in terms of mixed 1st- and 2nd-order kinetics. The temperature dependences of the component rate constants are unusual and both 1st- and 2nd-order components display negative activation energies, which are explained by invoking pre-equilibria. In addition, it is shown for the first time that 266 nm laser photolysis of BM-DBM solutions leads to formation of the triplet state of the keto (K) form with a lifetime of approximately 500 ns. Under these conditions the triplet state of the K form is quenched by oxygen.
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Affiliation(s)
- A Cantrell
- School of Chemistry and Physics, Lennard-Jones Laboratories, Keele University, Staffordshire, ST5 5BG, UK
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29
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Black HS, Okotie-Eboh G, Gerguis J. Diet potentiates the UV-carcinogenic response to beta-carotene. Nutr Cancer 2001; 37:173-8. [PMID: 11142090 DOI: 10.1207/s15327914nc372_9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The role of beta-carotene as an anticancer agent has been questioned as a result of clinical trials in which the incidence of nonmelanoma skin cancer was unchanged in patients receiving a beta-carotene supplement and in beta-carotene-supplemented smokers who suffered a significant increase in lung cancer occurrence. In laboratory studies, beta-carotene-supplemented semidefined diets, in contrast to earlier studies employing commercial closed-formula diets, not only failed to provide a protective effect to ultraviolet (UV) carcinogenesis but resulted in significant exacerbation. A rationale for this distinct carcinogenic response to beta-carotene rests with the stability of the carotenoid radical cation, believed to be dependent on the presence of other antioxidants for rapid repair, and suggests that response to beta-carotene depends on the presence and interaction with other dietary factors. Here, we report that diet potentiates beta-carotene-mediated exacerbation of UV carcinogenesis. Although the dietary factor(s) responsible for this effect is unidentified, these studies underscore the potential risk of beta-carotene supplementation in free-living populations where dietary status is widely varied.
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Affiliation(s)
- H S Black
- Baylor College of Medicine and Veterans Affairs Medical Center, Houston, TX 77030, USA
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30
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Mortensen A, Skibsted LH, Truscott TG. The interaction of dietary carotenoids with radical species. Arch Biochem Biophys 2001; 385:13-9. [PMID: 11361009 DOI: 10.1006/abbi.2000.2172] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dietary carotenoids react with a wide range of radicals such as CCl3O2*, RSO2*, NO2*, and various arylperoxyl radicals via electron transfer producing the radical cation of the carotenoid. Less strongly oxidizing radicals, such as alkylperoxyl radicals, can lead to hydrogen atom transfer generating the neutral carotene radical. Other processes can also arise such as adduct formation with sulphur-centered radicals. The oxidation potentials have been established, showing that, in Triton X-100 micelles, lycopene is the easiest carotenoid to oxidize to its radical cation and astaxanthin is the most difficult. The interaction of carotenoids and carotenoid radicals with other antioxidants is of importance with respect to anti- and possibly pro-oxidative reactions of carotenoids. In polar environments the vitamin E (alpha-tocopherol) radical cation is deprotonated (TOH*+ --> TO* + H+) and TO* does not react with carotenoids, whereas in nonpolar environments such as hexane, TOH*+ is converted to TOH by hydrocarbon carotenoids. However, the nature of the reaction between the tocopherol and various carotenoids shows a marked variation depending on the specific tocopherol homologue. The radical cations of the carotenoids all react with vitamin C so as to "repair" the carotenoid.
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Affiliation(s)
- A Mortensen
- Department of Dairy and Food Science, Royal Veterinary and Agricultural University, Frederiksberg, Denmark
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31
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Schröder C. TRIPLET STATE PROPERTIES OF C60PMMA CO-POLYMERS IN ORGANIC SOLUTION AND PMMA FILM. ACTA ACUST UNITED AC 2001. [DOI: 10.1081/fst-100104494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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32
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Getoff N. Pulse radiolysis studies of beta-carotene in oxygenated DMSO solution. Formation of beta-carotene radical cation. Radiat Res 2000; 154:692-6. [PMID: 11096427 DOI: 10.1667/0033-7587(2000)154[0692:prsoci]2.0.co;2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The spectroscopic and kinetic characteristics of beta-carotene radical cation (beta-carotene(.+)) were studied by pulse radiolysis in aerated DMSO solution. The buildup of beta-carotene(.+) with k(1) = (4.8 +/- 0.2) x 10(8) dm(3) mol(-1) s(-1) [lambda(max) = 942 nm, epsilon = (1.6 +/- 0.1) x 10(4) dm(3) mol(-1) cm(-1)] results from an electron transfer from beta-carotene to DMSO(.+). The beta-carotene(.+) species decays exclusively by first-order reaction, k = (2.1 +/- 0.1) x 10(3) s(-1), probably by two processes: (1) at low substrate concentration by hydrolysis and (2) at high concentrations also by formation of dimer radical cation (beta-carotene)(2)(.+). Under the experimental conditions, a small additional beta-carotene triplet-state absorption ((3)beta-carotene) in the range of 525 to 660 nm was observed. This triplet absorption is quenched by oxygen (k = 7 x 10(4) s(-1)), resulting in singlet oxygen ((1)O(2)), whose reactions can also lead to additional formation of beta-carotene(.+).
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Affiliation(s)
- N Getoff
- Ludwig Boltzmann Institute for Radiation Chemistry and Radiation Biology, c/o The University of Vienna, Austria
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33
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Burke M, Land EJ, McGarvey DJ, Truscott TG. Carotenoid triplet state lifetimes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000; 59:132-8. [PMID: 11332880 DOI: 10.1016/s1011-1344(00)00150-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Carotene and xanthophyll triplet lifetimes are found to depend on the concentration of the parent molecule. These results account for some of the variations in carotenoid triplet lifetimes reported previously. The rate constants obtained for ground state quenching correlate with the number of conjugated double bonds, the longer chain systems having higher quenching rate constants.
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Affiliation(s)
- M Burke
- School of Chemistry and Physics, Lennard-Jones Laboratories, Keele University, Staffs, UK
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34
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Martino DM, van Willigen H. Energy- and Electron-Transfer Quenching of Porphyrin Triplets by C60. J Phys Chem A 2000. [DOI: 10.1021/jp002680y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Débora M. Martino
- Department of Chemistry, University of Massachusetts at Boston, Boston, Massachusetts 02125
| | - Hans van Willigen
- Department of Chemistry, University of Massachusetts at Boston, Boston, Massachusetts 02125
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35
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Edge R, Land EJ, Rozanowska M, Sarna T, Truscott TG. Carotenoid Radical−Melanin Interactions. J Phys Chem B 2000. [DOI: 10.1021/jp9941561] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ruth Edge
- School of Chemistry and Physics, Keele University, Staffordshire, ST5 5BG, U.K., CRC Section of Drug Development, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, M20 4 BX, U.K., and Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Aleje Mickiewicza 3, 31-120, Kraków, Poland
| | - Edward J. Land
- School of Chemistry and Physics, Keele University, Staffordshire, ST5 5BG, U.K., CRC Section of Drug Development, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, M20 4 BX, U.K., and Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Aleje Mickiewicza 3, 31-120, Kraków, Poland
| | - Malgorzata Rozanowska
- School of Chemistry and Physics, Keele University, Staffordshire, ST5 5BG, U.K., CRC Section of Drug Development, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, M20 4 BX, U.K., and Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Aleje Mickiewicza 3, 31-120, Kraków, Poland
| | - Tadeusz Sarna
- School of Chemistry and Physics, Keele University, Staffordshire, ST5 5BG, U.K., CRC Section of Drug Development, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, M20 4 BX, U.K., and Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Aleje Mickiewicza 3, 31-120, Kraków, Poland
| | - T. George Truscott
- School of Chemistry and Physics, Keele University, Staffordshire, ST5 5BG, U.K., CRC Section of Drug Development, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, M20 4 BX, U.K., and Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Aleje Mickiewicza 3, 31-120, Kraków, Poland
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36
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He Z, Kispert LD. Effect of Electrolytes and Temperature on Dications and Radical Cations of Carotenoids: Electrochemical, Optical Absorption, and High-Performance Liquid Chromatography Studies. J Phys Chem B 1999. [DOI: 10.1021/jp991904d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhangfei He
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487
| | - Lowell D. Kispert
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487
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37
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Single electron transfer in the phototransformations of β-ionone in the presence of electron acceptors. J Photochem Photobiol A Chem 1999. [DOI: 10.1016/s1010-6030(99)00140-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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38
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Foley S, Berberan-Santos MN, Fedorov A, McGarvey DJ, Santos C, Gigante B. Photophysical Properties of Pseudo-Dihydro Derivatives of C70. J Phys Chem A 1999. [DOI: 10.1021/jp992495o] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sarah Foley
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001 Lisboa, Portugal; School of Chemistry and Physics, Keele University, Staffordshire ST5 5BG, UK; and INETI-IBQTA, Departamento de Tecnologia e Indústrias Químicas, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
| | - Mário N. Berberan-Santos
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001 Lisboa, Portugal; School of Chemistry and Physics, Keele University, Staffordshire ST5 5BG, UK; and INETI-IBQTA, Departamento de Tecnologia e Indústrias Químicas, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
| | - Aleksandre Fedorov
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001 Lisboa, Portugal; School of Chemistry and Physics, Keele University, Staffordshire ST5 5BG, UK; and INETI-IBQTA, Departamento de Tecnologia e Indústrias Químicas, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
| | - David J. McGarvey
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001 Lisboa, Portugal; School of Chemistry and Physics, Keele University, Staffordshire ST5 5BG, UK; and INETI-IBQTA, Departamento de Tecnologia e Indústrias Químicas, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
| | - Célia Santos
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001 Lisboa, Portugal; School of Chemistry and Physics, Keele University, Staffordshire ST5 5BG, UK; and INETI-IBQTA, Departamento de Tecnologia e Indústrias Químicas, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
| | - Bárbara Gigante
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001 Lisboa, Portugal; School of Chemistry and Physics, Keele University, Staffordshire ST5 5BG, UK; and INETI-IBQTA, Departamento de Tecnologia e Indústrias Químicas, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
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39
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Cantrell A, McGarvey DJ, Mulroy L, Truscott TG. Laser Flash Photolysis Studies of the UVA Sunscreen Mexoryl SX. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb08138.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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[36] Carotenoid photobleaching. Methods Enzymol 1999. [DOI: 10.1016/s0076-6879(99)99039-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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41
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Högemann C, Vauthey E. Investigation of the Competition between Electron and Energy Transfer in the Quenching of Aromatic Ketones in the Triplet State Using Picosecond Transient Grating Spectroscopy. J Phys Chem A 1998. [DOI: 10.1021/jp981810o] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Claudia Högemann
- Institute of Physical Chemistry of the University of Fribourg, Pérolles, CH-1700 Fribourg, Switzerland
| | - Eric Vauthey
- Institute of Physical Chemistry of the University of Fribourg, Pérolles, CH-1700 Fribourg, Switzerland
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42
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Abstract
Studies employing time-resolved techniques have shown that beta-carotene, astaxanthin, and lycopene behave quite distinctly with respect to radical quenching and stability, lycopene being the least stable. These results are compatible with the relative effects of the various carotenoids on ultraviolet (UV)-mediated carcinogenesis in mice in which a statistically significant exacerbation by beta-carotene and astaxanthin, but not by lycopene, was observed. Interactions between these carotenoids and vitamin C and E radicals not only provide a chemical basis to explain the failure of beta-carotene to provide benefit in recent clinical trials but suggest that future carotenoid supplementation studies should proceed with caution until carotenoid interactions and radical repair mechanism(s) are elucidated.
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Affiliation(s)
- H S Black
- Veterans Affairs Medical Center, Houston, TX 77030, USA
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43
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Garavelli M, Bernardi F, Olivucci M, Robb MA. DFT Study of the Reactions between Singlet-Oxygen and a Carotenoid Model. J Am Chem Soc 1998. [DOI: 10.1021/ja9805270] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marco Garavelli
- Contribution from Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy, and Department of Chemistry, King's College, London, Strand, London, UK WC2R 2LS
| | - Fernando Bernardi
- Contribution from Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy, and Department of Chemistry, King's College, London, Strand, London, UK WC2R 2LS
| | - Massimo Olivucci
- Contribution from Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy, and Department of Chemistry, King's College, London, Strand, London, UK WC2R 2LS
| | - Michael A. Robb
- Contribution from Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy, and Department of Chemistry, King's College, London, Strand, London, UK WC2R 2LS
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44
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Edge R, McGarvey DJ, Truscott TG. The carotenoids as anti-oxidants--a review. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1997; 41:189-200. [PMID: 9447718 DOI: 10.1016/s1011-1344(97)00092-4] [Citation(s) in RCA: 517] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Carotenoids are abundant in many fruits and vegetables and they play diverse roles in photobiology, photochemistry and medicine. This review concerns the reactivity of carotenoids with singlet oxygen and the interaction of carotenoids with a range of free radicals. Mechanisms associated with the anti- and pro-oxidant behaviour of carotenoids are discussed including carotenoid interactions with other anti-oxidants.
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Affiliation(s)
- R Edge
- Chemistry Department, Keele University, Staffs, UK
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45
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Broszeit G, Diepenbrock F, Gräf O, Hecht D, Heinze J, Martin HD, Mayer B, Schaper K, Smie A, Strehblow HH. Vinylogous β-Carotenes: Generation, Storage, and Delocalization of Charge in Carotenoids. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jlac.199719971106] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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46
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Kim JY, Furukawa Y, Tasumi M. Electronic absorption and Raman studies of the radical anion and dianion of a polyene molecule (19,19′,20,20′-tetranor-β,β-carotene). Chem Phys Lett 1997. [DOI: 10.1016/s0009-2614(97)00825-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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47
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Fournier T, Tavender SM, Parker AW, Scholes GD, Phillips D. Competitive Energy and Electron-Transfer Reactions of the Triplet State of 1-Nitronaphthalene: A Laser Flash Photolysis and Time-Resolved Resonance Raman Study. J Phys Chem A 1997. [DOI: 10.1021/jp970470o] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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48
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Bensasson R, Hill T, Land E, Leach S, McGarvey D, Truscott T, Ebenhoch J, Gerst M, Rüchardt C. Spectroscopy and photophysics of C60H18 and C60H36. Chem Phys 1997. [DOI: 10.1016/s0301-0104(96)00343-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Böhm F, Edge R, Land EJ, McGarvey DJ, Truscott TG. Carotenoids Enhance Vitamin E Antioxidant Efficiency. J Am Chem Soc 1997. [DOI: 10.1021/ja962512c] [Citation(s) in RCA: 191] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fritz Böhm
- Department of Dermatology (Charité) Humboldt University, 10117 Berlin, Germany Department of Chemistry Keele University, ST5 5BG, UK CRC Department of Biophysical Chemistry Paterson Institute for Cancer Research Christie Hospital NHS Trust, Manchester, M20 9BX, UK
| | - Ruth Edge
- Department of Dermatology (Charité) Humboldt University, 10117 Berlin, Germany Department of Chemistry Keele University, ST5 5BG, UK CRC Department of Biophysical Chemistry Paterson Institute for Cancer Research Christie Hospital NHS Trust, Manchester, M20 9BX, UK
| | - Edward J. Land
- Department of Dermatology (Charité) Humboldt University, 10117 Berlin, Germany Department of Chemistry Keele University, ST5 5BG, UK CRC Department of Biophysical Chemistry Paterson Institute for Cancer Research Christie Hospital NHS Trust, Manchester, M20 9BX, UK
| | - David J. McGarvey
- Department of Dermatology (Charité) Humboldt University, 10117 Berlin, Germany Department of Chemistry Keele University, ST5 5BG, UK CRC Department of Biophysical Chemistry Paterson Institute for Cancer Research Christie Hospital NHS Trust, Manchester, M20 9BX, UK
| | - T. George Truscott
- Department of Dermatology (Charité) Humboldt University, 10117 Berlin, Germany Department of Chemistry Keele University, ST5 5BG, UK CRC Department of Biophysical Chemistry Paterson Institute for Cancer Research Christie Hospital NHS Trust, Manchester, M20 9BX, UK
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