Carotenoids as scavengers of free radicals in a fenton reaction: antioxidants or pro-oxidants?

Polyakov, Nikolay E.; Leshina, Tatyana V.; Konovalova, Tatyana A.; Kispert, Lowell D.

doi:10.1016/s0891-5849(01)00598-6

Cited by 120 publications

(116 citation statements)

References 21 publications

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“…• DMPO-OH, and • DMPO-CX spin adducts was observed, respectively, in accord with our previous experiments and the data already published (Polyakov et al 2001;Valdez et al 2002;Kovács et al 2004;Polovka 2006). The addition of the grape skin extracts into the system resulted in a decrease of the spin adduct concentration as a result of competitive reactions between the antioxidants, generated free radicals, and spin trap (Polovka et al 2003;Polovka 2006;Staško et al 2007).…”

Section: Epr Experimentssupporting

confidence: 92%

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Multi-experimental characterisation of grape skin extracts

Šťavíková¹,

Polovka²,

Hohnová³

et al. 2008

Czech J. Food Sci.

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Abstract:Grape skins contain a plenty of different flavonoids, most of them revealing significant antioxidant properties. In this contribution, a complex study is presented of grape skin ethanol extracts, prepared from grape skins of two vine grape varieties, Svatovavřinecké (St. Laurent) and Alibernet. Extracts were prepared from two different amounts of lyophilised grape skin powders using the pressurised fluid extraction (PFE). The antioxidant activity of the extracts was tested by EPR spectroscopy in Fenton system generating reactive radicals (• OH, O 2 -• , • R) followed by spin trapping technique. In addition, radical scavenging activity of the extracts was assessed applying 2,2-diphenyl-1-picrylhydrazyl ( • DPPH) free radical and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) cation radical (ABTS •+ ) assays. Total phenolic content (TPC) of the individual extracts and their tristimulus colour values (CIE Lab) were evaluated, using an UV-VIS spectrophotometer. All the data obtained were subsequently correlated and discriminated, using the multivariate statistics, involving the canonical discriminant analysis, principal component analysis, and canonical correlation analysis. Results obtained indicated that PFE is a suitable extraction technique, only slightly influencing antioxidant ability as well as composition of the so-prepared extracts. The influence of extraction conditions on the entire monitored characteristics was insignificant.

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Section: Epr Experimentssupporting

confidence: 92%

“…• OH) followed by spin trapping technique, with the use 5,5-dimethylpyrroline-Noxide (DMPO) as the spin trap (Polyakov et al 2001). In addition, the radical scavenging activity of the extracts was assessed applying 2,2-diphenyl-1-picrylhydrazyl (…”

Section: Methodsmentioning

confidence: 99%

Multi-experimental characterisation of grape skin extracts

Šťavíková¹,

Polovka²,

Hohnová³

et al. 2008

Czech J. Food Sci.

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“…In fact, recent studies have provided evidence that retinol could enhance carcinogenesis, especially at doses that exceed the normal dietary intake or in conditions of enhanced oxidative stress (40)(41)(42)(43). This evidence would be supported by the results of a number of experimental studies in different biological systems, in vivo and in vitro, showing that pro-vitamin A, β-carotene, retinol and retinoids have pro-oxidant properties, which might lead to cell oxidative damage and carcinogenesis (44)(45)(46)(47)(48). Thus, in the present scenario of apparently contradictory evidence, further research is needed in order to elucidate the mechanism(s) by which retinoids may influence human carcinogenesis.…”

Section: Discussionmentioning

confidence: 93%

Influence of a 50 Hz magnetic field and of all-trans‑retinol on the proliferation of human cancer cell lines

Trillo

2012

Int J Oncol

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Abstract. In vitro exposure to power frequency magnetic fields (MF) has been reported to influence cell proliferation and differentiation. However, the nature of the response of different human cancer cell types to these fields has not been sufficiently characterized. The present work investigates the response of two proliferating human cell lines of neuroblastoma (NB69) and hepatocarcinoma (HepG2) to a 42 h, intermittent treatment with a weak, 100 µT, 50 Hz MF, alone or in combination with 0.5 µM all-trans-retinol (ROL), a retinoid currently applied in oncostatic therapies. In each experimental replicate the cell samples were submitted to one of the following treatment combinations: MF+/ROL+, MF+/ ROL-, MF-/ROL+ or MF-/ROL-. The proliferative response was determined by cell counting (Trypan blue exclusion), BrdU incorporation and by spectrophotometric analysis of total protein and DNA content. The results show that when administered separately, the two treatments, MF and ROL, significantly enhanced cell proliferation in both cell lines. In NB69 simultaneous administration of MF and ROL induced an additive effect on cell proliferation, associated to increased DNA content. By contrast, in HepG2 the ROL-induced cell proliferation and increased protein content were partially blocked by simultaneous exposure to MF. Taken together, these data show that both agents, a weak MF and ROL at a low concentration, induce proliferative responses in the two assayed human cell lines. However, significant differences were observed between the responses of the two cellular species to the combined treatment with ROL and MF, indicating that the mechanisms underlying the cellular response to each of the two agents can mutually interact in a manner that is cell type-specific.

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“…Polyakov et al stated that β-carotene offers little protection against metal-induced lipid peroxidation [82]. Indeed, as unsaturated lipids, carotenoids can be oxidised by transition metal especially at low pH [83].…”

Section: Effect Of Food Compositionmentioning

confidence: 99%

Degradation of β-carotene during fruit and vegetable processing or storage: reaction mechanisms and kinetic aspects: a review

Pénicaud¹,

Achir²,

Dhuique-Mayer³

et al. 2011

Fruits

166

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-Introduction. Food processing significantly lowers the quality of fruits and vegetables, which is a major concern for the food industry. Micronutrients are particularly affected, and among them β-carotene, which exhibits very interesting sensory, nutritional and biological properties. The literature concerning β-carotene degradation is extensive, but the conclusions are very different as a function of the biological, chemical and food transformation points of view. This paper proposes a synthesis of complementary approaches in the study of β-carotene during food transformation and storage. Degradation reactions. Degradation compounds are numerous, including isomers, epoxides, apocarotenones, apocarotenals and short-chain cleavage products, among them some flavour compounds. A detailed reaction scheme of isomerisation and autoxidation of β-carotene could be deduced from the literature data. The main pathways are well documented, but the global reaction scheme is still incomplete. Furthermore, most of the mechanistic studies are carried out in model systems, thus data may misrepresent β-carotene behaviour in real food products. Kinetics during processing and storage. The determination of degradation kinetics permits the identification of the fastest reactions, i.e., generally those with the greatest impact, and also the quantification of the effect of the factors which can lower β-carotene content. Temperature, occurrence of oxygen, food composition and food structure are shown to affect the β-carotene loss rate significantly. However, the methodologies used to obtain the kinetic parameters are of major importance, and finally, most of the results found in the literature are specific to a study and difficult to generalise. Discussion and conclusion. Mechanistic and kinetic approaches each provide interesting data to improve understanding and monitoring of β-carotene. The combination of all this data, together with thermodynamic and analytical considerations, permits the building of observable reaction schemes which can further be transcribed through mathematical models. By this multidisciplinary approach, scarcely used for the time being, knowledge could be capitalised and useful tools could be developed to improve β-carotene retention during food processing and storage.France / fruits / vegetables / storage / processing / carotenoids / isomerisation / oxidation / degradation / chemical reactions La dégradation du β-carotène au cours de la transformation ou du stockage des fruits et des légumes : mécanismes réactionnels et aspects cinétiques : une revue.Résumé -Introduction. La diminution significative de la qualité des fruits et légumes au cours de leur transformation est une préoccupation majeure de l'industrie alimentaire. Les micronutriments sont particulièrement affectés, et, parmi eux, le β-carotène qui présente d'intéressantes propriétés sensorielles, nutritionnelles et biologiques. La littérature traitant de la dégradation du β-carotène est très dense, mais la nature des conclusions diffère en fo...

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Carotenoids as scavengers of free radicals in a fenton reaction: antioxidants or pro-oxidants?

Cited by 120 publications

References 21 publications

Multi-experimental characterisation of grape skin extracts

Multi-experimental characterisation of grape skin extracts

Influence of a 50 Hz magnetic field and of all-trans‑retinol on the proliferation of human cancer cell lines

Degradation of β-carotene during fruit and vegetable processing or storage: reaction mechanisms and kinetic aspects: a review

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