The β-carotene dilemma: ESR study with coordinated peroxyl radicals

2006 ◽  
Vol 60 (3) ◽  
Author(s):  
A. Tkáč ◽  
G. Scott
Keyword(s):  
Vitamin E ◽  
Peroxyl Radical ◽  
Cell Damage ◽  
Transition Metal Ions ◽  
Spin Trapping ◽  
Peroxyl Radicals ◽  
Polar Solvents ◽  
Primary Attack ◽  
Peroxy Group ◽  
Β Carotene

AbstractThe apparently unpredictable behaviour of β-carotene in the supplementation of the diet of smokers is discussed in the light of the reactions of peroxyl radicals with β-carotene in the absence of oxygen. The decay of tert-butylperoxyl radicals in the presence of β-carotene was studied at ambient temperature in non-polar solvents by ESR spectroscopy. The primary reaction in the absence of oxygen is interpreted as a spin-trapping effect of a peroxyl radical by β-carotene producing an intermediate labile free radical, which disappears after recombination with a second tert-butylperoxyl radical. The result is the transformation of β-carotene to a diamagnetic compound with two peroxy bonds. In the presence of chelating transition metals with unpaired d-electrons as electron donors the peroxy group of the oxidized β-carotene can be split to alkoxyl free radicals. The primary attack of tert-butylperoxyl radicals is completely inhibited in the presence of vitamin E followed by production of free aryloxy radicals and the presence of oxygen has no significant effect on this reaction. Spin-trapping of peroxyl radicals by the double bond of vitamin A leads to its oxidation in the absence of vitamin E.Transition metal ions such as Co, Cr, Fe, and Mn, known to be present in the aerosol of cigarette smoke, homolyse the peroxyl bonds of peroxidised β-carotene, which results in cell damage.

Evidence of Trolox and some gallates as synergistic protectors of erythrocytes against peroxyl radicals

1998 ◽  
Vol 76 (4) ◽  
pp. 661-664 ◽  
Author(s):  
J Wu ◽  
H Sugiyama ◽  
L -H Zeng ◽  
D Mickle ◽  
T -W Wu
Keyword(s):  
Antioxidant Activity ◽  
Vitamin E ◽  
Protective Effect ◽  
Propyl Gallate ◽  
Peroxyl Radical ◽  
Human Erythrocytes ◽  
Peroxyl Radicals ◽  
Methyl Ethyl ◽  
Radical Initiator ◽  
Individual Contributions

The peroxidation of human erythrocytes induced by peroxyl radical initiator and its inhibition by several gallate esters (e.g., propyl, methyl, ethyl) and Trolox (a more polar analogue of vitamin E) have been studied. The antioxidant activity was determined on erythrocytes against hemolysis generated by a thermal activator, 2,2prime-azobis-(2-amidinopropane)dihydrogenchloride. It was found that propyl gallate and its two analogues were more effective than Trolox in preventing cell lysis. However, the combination of gallate esters and Trolox produced a protective effect exceeding the arithmetic sum of their individual contributions. These perceived synergisms occur at more than one level of Trolox at a given level of a gallate ester.Key words: Trolox, gallates, synergism, peroxyl radicals.

Is the Oxygen Radical Absorbance Capacity (ORAC) Method a Peroxyl-radical Scavenging Assay?

2010 ◽  
Vol 224 (06) ◽  
pp. 921-928 ◽  
Author(s):  
Yoshimi Sueishi ◽  
Daisuke Yoshioka ◽  
Shigeru Oowada ◽  
Nobuyuki Endoh ◽  
Shunji Kohri ◽  
...  
Keyword(s):  
Peroxyl Radical ◽  
Radical Scavenging Activity ◽  
Aqueous Media ◽  
Radical Scavenging ◽  
Spin Trapping ◽  
Oxygen Radical ◽  
Water Soluble ◽  
Oxygen Radical Absorbance Capacity ◽  
Peroxyl Radicals ◽  
Radical Initiator

AbstractThe oxygen radical absorbance capacity (ORAC) method employs a water soluble azo-radical initiator, AAPH (2,2’-azobis(2-amidinopropane) dihydrochloride) as a free radical generator, by which the fluorescent probe fluorescein is damaged to result in the loss of fluorescence. Antioxidants can protect the probe from the damage and the degree of protection is quantified. Because AAPH has been used as a lipid-peroxidation reagent, “oxygen radical” in ORAC is generally accepted as peroxyl radicals; however, in the present spin trapping experiments using a newly developed spin trap, CYPMPO, there was no indication of peroxyl-radical formation in AAPH decomposition in aqueous media. These spin trapping studies demonstrated that alkoxyl (RO·) radical adduct was the sole product of AAPH decomposition. In contrast, alkyl-peroxyl (ROO·) radical was spin-trapped during the decomposition of a lipid soluble azo-radical initiator AIBN (azobis(isobutyronitrile)) in non-aqueous media. We speculate that alkyl-peroxyl radicals are short-lived in water, rapidly converted into alkoxyl radicals. Although the possibility that ORAC method monitors peroxyl-radical scavenging activity cannot be completely eliminated, spin trapping evidence strongly indicates that ORAC method is a scavenging capacity assay for alkoxyl radicals.

Isomerization of the Isoprene Hydroxy Nitrates and Formation of Orthonitrite Compounds

2019 ◽  
Author(s):  
Gabriel da Silva
Keyword(s):  
Hydroxy Group ◽  
Peroxyl Radical ◽  
Branching Fractions ◽  
Membered Ring ◽  
Low Energy ◽  
Peroxyl Radicals ◽  
Aerosol Formation ◽  
Subsequent Removal ◽  
Ring Compounds ◽  
Group Migration

Atmospheric oxidation of isoprene produces significant yields of eight unique nitrate 11 compounds, each with a β- or δ-hydroxy group. These isoprene hydroxy nitrates (ISOPNs) 12 significantly impact upon global NOx budgets, O3 levels, and aerosol formation. 13 Uncertainties exist, however, in our understanding of ISOPN chemistry, particularly in their 14 yields from the reaction of isoprene peroxyl radicals with NO. This study describes novel 15 isomerization reactions of the ISOPNs, identified through the application of computational 16 chemistry techniques. These reactions produce saturated polycyclic orthonitrite compounds 17 via attack of the R–NO2 group on the vinyl moiety. For the δ-hydroxy nitrates, low-energy 18 isomerization pathways exist to six-membered ring compounds that are around 5 kcal mol-1 19 exothermic. These reactions proceed with barriers around 15 kcal mol-1 below the 20 respective peroxyl radical + NO reactants and yield orthonitrites that can further isomerize 21 to β-hydroxy ISOPNs. Moreover, the δ-hydroxy nitrates can directly interconvert with their β 22 substituted counterparts via NO3 group migration, with barriers that are lower yet. It follows 23 that β-hydroxy nitrates may be stabilized in the δ-hydroxy form, and vice versa. Moreover, 24 the lowest-energy pathway for dissociation of the δ-hydroxy ISOPNs is for the formation of 25 β-hydroxy alkoxyl radicals, and because of this established branching fractions between the 26 various isoprene peroxyl radicals may require re-evaluation. The results presented here also 27 suggest that ISOPNs may be stabilized to some extent in their saturated orthonitrite forms, 28 which has implications for both the total nitrate yield and for their subsequent removal by 29 OH, O3, and photolysis.<br><br>

scholarly journals Vitamin A and E Homologues Impacting the Fate of Acrylamide in Equimolar Asparagine-Glucose Model System

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 993
Author(s):  
Su Lee Kuek ◽  
Azmil Haizam Ahmad Tarmizi ◽  
Raznim Arni Abd Razak ◽  
Selamat Jinap ◽  
Maimunah Sanny
Keyword(s):  
Vitamin E ◽  
Linear Regression ◽  
Vitamin A ◽  
Regression Model ◽  
Linear Regression Model ◽  
Model System ◽  
Concentration Increase ◽  
Acrylamide Formation ◽  
Β Carotene

This study aims to evaluate the influence of Vitamin A and E homologues toward acrylamide in equimolar asparagine-glucose model system. Vitamin A homologue as β-carotene (BC) and five Vitamin E homologues, i.e., α-tocopherol (AT), δ-tocopherol (DT), α-tocotrienol (ATT), γ-tocotrienol (GTT), and δ-tocotrienol (DTT), were tested at different concentrations (1 and 10 µmol) and subjected to heating at 160 °C for 20 min before acrylamide quantification. At lower concentrations (1 µmol; 431, 403, 411 ppm, respectively), AT, DT, and GTT significantly increase acrylamide. Except for DT, enhancing concentration to 10 µmol (5370, 4310, 4250, 3970, and 4110 ppm, respectively) caused significant acrylamide formation. From linear regression model, acrylamide concentration demonstrated significant depreciation over concentration increase in AT (Beta = −83.0, R2 = 0.652, p ≤ 0.05) and DT (Beta = −71.6, R2 = 0.930, p ≤ 0.05). This study indicates that different Vitamin A and E homologue concentrations could determine their functionality either as antioxidants or pro-oxidants.

scholarly journals Biochemical Validation of a Self-Administered Food Frequency Questionnaire to Assess Diet Using Carotenoids and Vitamins E and D in Male Adolescents in Spain

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 750
Author(s):  
Leyre Notario-Barandiaran ◽  
Eva-María Navarrete-Muñoz ◽  
Desirée Valera-Gran ◽  
Elena Hernández-Álvarez ◽  
Encarnación Donoso-Navarro ◽  
...  
Keyword(s):  
Vitamin E ◽  
Food Frequency Questionnaire ◽  
Vegetable Intake ◽  
Correlation Coefficients ◽  
Fruit And Vegetable Intake ◽  
Fruit And Vegetable ◽  
Sample Mean ◽  
Food Frequency ◽  
Male Adolescents ◽  
Β Carotene

Reliable tools to evaluate diet are needed, particularly in life periods such as adolescence in which a rapid rate of growth and development occurs. We assessed the biochemical validity of a self-administered food frequency questionnaire (FFQ) in a sample of Spanish male adolescents using carotenoids and vitamin E and D data. We analyzed data from 122 male adolescents aged 15–17 years of the INMA-Granada birth cohort study. Adolescents answered a 104-item FFQ and provided a non-fasting blood sample. Mean daily nutrient intakes and serum concentration were estimated for main carotenoids (lutein-zeaxanthin, β-cryptoxanthin, lycopene, α-carotene and β-carotene), vitamins E and D and also for fruit and vegetable intake. Pearson correlation coefficients (r) and the percentage of agreement (same or adjacent quintiles) between serum vitamin concentrations and energy-adjusted intakes were estimated. Statistically significant correlation coefficients were observed for the total carotenoids (r = 0.40) and specific carotenoids, with the highest correlation observed for lutein–zeaxanthin (r = 0.42) and the lowest for β-carotene (0.23). The correlation coefficient between fruit and vegetable intake and serum carotenoids was 0.29 (higher for vegetable intake, r = 0.33 than for fruit intake, r = 0.19). Low correlations were observed for vitamin E and D. The average percentage of agreement for carotenoids was 55.8%, and lower for vitamin E and D (50% and 41%, respectively). The FFQ may be an acceptable tool for dietary assessment among male adolescents in Spain.

scholarly journals Dietary and circulating vitamin C, vitamin E, β-carotene and risk of total cardiovascular mortality: a systematic review and dose–response meta-analysis of prospective observational studies

2019 ◽  
Vol 22 (10) ◽  
pp. 1872-1887 ◽  
Author(s):  
Ahmad Jayedi ◽  
Ali Rashidy-Pour ◽  
Mohammad Parohan ◽  
Mahdieh Sadat Zargar ◽  
Sakineh Shab-Bidar
Keyword(s):  
Systematic Review ◽  
Vitamin E ◽  
Vitamin C ◽  
Dose Response ◽  
Observational Studies ◽  
Meta Analysis ◽  
Dietary Intakes ◽  
Relative Risks ◽  
Β Carotene ◽  
Cvd Mortality

AbstractObjectiveThe present review aimed to quantify the association of dietary intake and circulating concentration of major dietary antioxidants with risk of total CVD mortality.DesignSystematic review and meta-analysis.SettingSystematic search in PubMed and Scopus, up to October 2017.ParticipantsProspective observational studies reporting risk estimates of CVD mortality across three or more categories of dietary intakes and/or circulating concentrations of vitamin C, vitamin E and β-carotene were included. A random-effects meta-analysis was conducted.ResultsA total of fifteen prospective cohort studies and three prospective evaluations within interventional studies (320 548 participants and 16 974 cases) were analysed. The relative risks of CVD mortality for the highest v. the lowest category of antioxidant intakes were as follows: vitamin C, 0·79 (95 % CI 0·68, 0·89; I2=46 %, n 10); vitamin E, 0·91 (95 % CI 0·79, 1·03; I2=51 %, n 8); β-carotene, 0·89 (95 % CI 0·73, 1·05; I2=34 %, n 4). The relative risks for circulating concentrations were: vitamin C, 0·60 (95 % CI 0·42, 0·78; I2=65 %, n 6); α-tocopherol, 0·82 (95 % CI 0·76, 0·88; I2=0 %, n 5); β-carotene, 0·68 (95 % CI 0·52, 0·83; I2=50 %, n 6). Dose–response meta-analyses demonstrated that the circulating biomarkers of antioxidants were more strongly associated with risk of CVD mortality than dietary intakes.ConclusionsThe present meta-analysis demonstrates that higher vitamin C intake and higher circulating concentrations of vitamin C, vitamin E and β-carotene are associated with a lower risk of CVD mortality.

Synthesis Of Copper Nanometal Coupled With Vitamin-E And Investigating Its Potential To Control Oxidative Cell Damage And Microbial Spoilage In Seafood

2021 ◽  
Vol 23 (08) ◽  
pp. 678-693
Author(s):  
Haris. V.T ◽  
◽  
Manohar. M ◽  
Kuppannan Gobianand ◽  
◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Vitamin E ◽  
Mtt Assay ◽  
Cell Damage ◽  
Green Emission ◽  
Plate Count ◽  
Diffusion Method ◽  
Inhibitory Effects ◽  
Microbial Spoilage ◽  
Spoilage Bacteria

The metabolism of spoilage organism in the seafood is a major cause of fish spoilage. Lipid oxidation leads to production of intermediate peroxides causing bad odor and offflavour producing compounds. Hence, based on the hurdle technology method and applications of nanotechnology, the inhibitory effects of copper oxide nanoparticles coupled with vitamin-E (CuONPs+VE) was investigated with the aim of controlling the oxidative cell damage in seafood by estimating Reacting Oxygen Species (ROS) using 2’,7’- dichlorodihydrofluorescein diacetate (DCF) and preventing microbial spoilage by studying the cell viability using MTT assay in the present study. The MTT assay reveals that the CuONPs+VE inhibited the metabolic activity of spoilage bacteria which was confirmed from the inhibition percentage values against the test organisms. The CuONPs+VE exposed Escherichia coli reduced upto 86 ± 0.57% after enumerating the CFU in a Plate Count Agar media. Salmonella sp and Shigella sp exhibited 89 ± 1.04% and 85 ± 0.25% respectively. The qualitative inhibitory effect of Nanometal vitamin complex against three test bacteria, were evaluated by agar diffusion method. Among the four different concentrations of Nanometal vitamin complex, the higher concentration (4X – 40μg/ml) exhibited maximum inhibitory effects in terms of zone of clearance. Against Escherichia coli, 12.3 ± 1.25mm of inhibitory zones were found evident. Salmonella sp showed 15.6 ± 0.57mm of inhibitory zones and Shigella sp revealed the inhibition zone of about 16.6 ± 1.04mm. The anti-oxidative defence mechanisms operating in the cells for scavenging of ROS was performed using DCF. The cells which are pre-incubated with CuONPs+VE and then exposed to H2O2 show insignificant green emission indicating a clear advantage of the nanoparticle form of vitamin-E (CuONPs+VE) in preventing oxidative cell death.

scholarly journals Blood antioxidant nutrients in riparian villagers of the Brazilian Amazon: its associations with wet/dry seasons and modulation by sociodemographic determinants

2016 ◽  
Vol 24 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Juliana Valentini ◽  
Carlos José Sousa Passos ◽  
Solange Cristina Garcia ◽  
Robert Davidson ◽  
Marc Lucotte ◽  
...  
Keyword(s):  
Vitamin E ◽  
Reference Range ◽  
Brazilian Amazon ◽  
Individual State ◽  
River Region ◽  
Baseline Information ◽  
Sociodemographic Determinants ◽  
Dry Seasons ◽  
The Individual ◽  
Β Carotene

Abstract This study associates blood antioxidants like copper (Cu), manganese (Mn), selenium (Se), zinc (Zn), β-carotene, lycopene and vitamins (A and E) to sociodemographic features and seasonality in communities from the Tapajós River region, Brazilian Amazon. We observed increased Mn, Se and Zn levels compared to the average Brazilian population, whereas this is only the case for β-carotene in the rainy season. Lycopene levels fall within the reference range, although lower than those found in other Brazilian regions. Cu, Se, Zn, β-carotene, lycopene and vitamin E levels vary among seasons. β-carotene, Mn and Se vary among communities. Se and Zn vary with smoking habits and sex, respectively. In addition, β-carotene and vitamins (A and E) are altered by alcohol consumption. Villagers who both farmed and fished present higher Cu and lower β-carotene levels than participants with a single occupation. Vitamin E levels depend upon the individual state of origin. These data provide important baseline information for antioxidant status in this Amazonian riparian population.

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