Comparing the Relative Reactivities of Food and Vitamin Molecules Toward Electrochemically Generated Superoxide in Dimethylformamide

Lauw, Sherman Jun Liang; Yeo, Joyce Y. H.; Zhong, Cheng; Webster, Richard D.

doi:10.1002/celc.201600790

Cited by 8 publications

(6 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…into RO − takes place since the overall process appears to remain one‐electron driven – as observed by the lack of increase in cathodic current magnitudes after the repeated addition of substrates. This is also supported by digital simulations studies in previous work ,. In a similar vein, HO 2 − reacts with another molecule of ROH in which it is converted to H 2 O 2 (eq.…”

Section: Resultssupporting

confidence: 84%

“…Due to the immense importance and implications of this toxicant, another area of interest has been the voltammetric examination of the reactions between electrochemically generated O 2 .− and different classes of molecules and substances. Included in this discipline of study have primarily been works directed toward the examination of scavenging capabilities of prevalent antioxidant molecules such as flavonoids and (poly)phenolic compounds ,. However, because these compounds are often constituted of complex chemical structures comprising of multiple functional groups, it can sometimes be challenging to unravel the exact characteristic or facet responsible for the perceived reactivity or lack thereof.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparing the Relative Reactivities of Structurally Varied Alcohols toward Electrochemically Generated Superoxide

et al. 2017

Self Cite

View full text Add to dashboard Cite

is a free-radical anion of the reactive oxygen species (ROS) family. In the present study, the relative reactivities of 14 structurally varied aliphatic alcohols toward electrochemically generated O 2 * À were investigated in solutions of N,Ndimethylformamide by using cyclic voltammetry (CV). Upon the stepwise addition of each substrate, the chemical reversibility of the one-electron voltammetric reduction of the dioxygen (O 2 ) to O 2 * À was found to decrease, which enabled the extent of radical inhibition to be determined by measuring the resultant oxidative peak current (I pa ) magnitudes on the reverse scan of the CV. Based on the electrochemical responses gathered, best fit plots of the percentage decrease in the anodic peak current (%DI pa ) against the concentration of substrate added were obtained and compared according to the different classes of alcohols that were examined (linear, fluorinated, branched, and poly-hydroxylated). In addition, different parameters, such as electronic effects, steric effects, degree of hydroxylation, and kinetic effects that affect the O 2 * À scavenging abilities of the alcohols, are also discussed.

show abstract

Section: Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Comparing the Relative Reactivities of Structurally Varied Alcohols toward Electrochemically Generated Superoxide

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Curiously, there are only a few assays that exploit electrochemical methods to investigate the reactivity of antioxidants with radicals. Several recent studies are reporting the development of modified electrodes to monitor the radical chain reactions [15–19]. Deutchoua et al.…”

Section: Introductionmentioning

confidence: 99%

Radical Scavenging Activity of Antioxidants by Cyclic Voltammetry

et al. 2020

View full text Add to dashboard Cite

This work investigates the reactivity of individual antioxidants with the free radicals generated by 2,2′‐azobis(isobutironitrile) (AIBN). The consumption of antioxidants was followed by cyclic voltammetry. The fitting of such decay with a kinetic model yielded the rate constant of radical formation and the rate constant of radical inhibition exerted by each antioxidant. The antioxidant efficiency was defined as the ratio between and . The following ranking of antioxidants was obtained: α‐tocopherol≫catechin≫retinyl acetate≫hydroxytyrosol≫oleuropein≫caffeic acid. Overall, the approach shows the utility of cyclic voltammetry to investigate the kinetic rates at which antioxidants react with radicals.

show abstract

“…In the presence of oxygen, α–TO − was found to be oxidized to α–TO • with the corresponding formation of the superoxide anion radical, (O 2 −• ) [ 114 ]. Therefore, while α–TO − can generate O 2 −• (in the presence of O 2 ), α–TOH is well known to be a scavenger (destroyer) of superoxide radicals via a hydrogen atom transfer mechanism [ 115 , 116 ].…”

Section: Spectroscopic Characterization Of Each Class Of Compoundmentioning

confidence: 99%

“…The author gratefully acknowledges the many academic collaborators, post-doctoral fellows, graduate, and undergraduate students who have worked on aspects of this study and named in references [ 49 , 50 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 74 , 75 , 76 , 80 , 81 , 84 , 85 , 86 , 87 , 88 , 115 , 128 ].…”

Section: Acknowledgmentsmentioning

confidence: 99%

Electrochemical and Spectroscopic Characterization of Oxidized Intermediate Forms of Vitamin E

Webster

2022

Molecules

Self Cite

View full text Add to dashboard Cite

Vitamin E, a collection of lipophilic phenolic compounds based on chroman-6-ol, has a rich and fascinating oxidative chemistry involving a range of intermediate forms, some of which are proposed to be important in its biological functions. In this review, the available electrochemical and spectroscopic data on these oxidized intermediates are summarized, along with a discussion on how their lifetimes and chemical stability are either typical of similar phenolic and chroman-6-ol derived compounds, or atypical and unique to the specific oxidized isomeric form of vitamin E. The overall electrochemical oxidation mechanism for vitamin E can be summarized as involving the loss of two-electrons and one-proton, although the electron transfer and chemical steps can be controlled to progress along different pathways to prolong the lifetimes of discreet intermediates by modifying the experimental conditions (applied electrochemical potential, aqueous or non-aqueous solvent, and pH). Depending on the environment, the electrochemical reactions can involve single electron transfer (SET), proton-coupled electron transfer (PCET), as well as homogeneous disproportionation and comproportionation steps. The intermediate species produced via chemical or electrochemical oxidation include phenolates, phenol cation radicals, phenoxyl neutral radicals, dications, diamagnetic cations (phenoxeniums) and para–quinone methides. The cation radicals of all the tocopherols are atypically long-lived compared to the cation radicals of other phenols, due to their relatively weak acidity. The diamagnetic cation derived from α–tocopherol is exceptionally long-lived compared to the diamagnetic cations from the other β–, γ– and δ–isomers of vitamin E and compared with other phenoxenium cations derived from phenolic compounds. In contrast, the lifetime of the phenoxyl radical derived from α–tocopherol, which is considered to be critical in biological reactions, is typical for what is expected for a compound with its structural features. Over longer times via hydrolysis reactions, hydroxy para–quinone hemiketals and quinones can be formed from the oxidized intermediates, which can themselves undergo reduction processes to form intermediate anion radicals and dianions. Methods for generating the oxidized intermediates by chemical, photochemical and electrochemical methods are discussed, along with a summary of how the final products vary depending on the method used for oxidation. Since the intermediates mainly only survive in solution, they are most often monitored using UV-vis spectroscopy, FTIR or Raman spectroscopies, and EPR spectroscopy, with the spectroscopic techniques sometimes combined with fast photoinitiated excitation and time-resolved spectroscopy for detection of short-lived species.

show abstract

Comparing the Relative Reactivities of Food and Vitamin Molecules Toward Electrochemically Generated Superoxide in Dimethylformamide

Cited by 8 publications

References 66 publications

Comparing the Relative Reactivities of Structurally Varied Alcohols toward Electrochemically Generated Superoxide

Comparing the Relative Reactivities of Structurally Varied Alcohols toward Electrochemically Generated Superoxide

Radical Scavenging Activity of Antioxidants by Cyclic Voltammetry

Electrochemical and Spectroscopic Characterization of Oxidized Intermediate Forms of Vitamin E

Contact Info

Product

Resources

About