Electron-transfer mechanism in radical-scavenging reactions by a vitamin E model in a protic medium

Nakanishi, Ikuo; Kawashima, Tomonori; Ohkubo, Kei; Kanazawa, Hideko; Inami, Keiko; Mochizuki, Masahito; Fukuhara, Kiyoshi; Okuda, Haruhiro; Ozawa, Toshihiko; Itoh, Shinobu; Fukuzumi, Shunichi; Ikota, Nobuo

doi:10.1039/b416572a

Cited by 113 publications

(83 citation statements)

References 21 publications

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“…The oxidation potentials of complexes (F 1 1/2 , V) are more electropositive than the potential of one-electron reduction of DPPH radical (F red 1/2 ¼ 0.3 V) in given experimental conditions. This fact leads to increase of Gibbs free energy in electron transfer process [DG 0 ¼ e(F 1 1/2 À F red 1/2 ) > 0] [45]. These data are in accordance with values of calculated velocity constant (Table 1).…”

Section: Radical Scavenging Reactions Of the Target Complexes In Deaesupporting

confidence: 87%

Radical scavenging activity of sterically hindered catecholate and o-amidophenolate complexes of LSbVPh3 type

Smolyaninov

Antonova

Poddel’sky

et al. 2011

Journal of Organometallic Chemistry

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Section: Radical Scavenging Reactions Of the Target Complexes In Deaesupporting

confidence: 87%

Radical scavenging activity of sterically hindered catecholate and o-amidophenolate complexes of LSbVPh3 type

Smolyaninov

Antonova

Poddel’sky

et al. 2011

Journal of Organometallic Chemistry

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“…This would allow a more accurate and reasonable comparison of the efficiencies of compounds and extracts analysed, since they were evaluated under similar experimental conditions . Indeed, antioxidant properties can varied strongly depending on the nature of the solvent use for the analysis . Recently, acetonitrile was successfully used as solvent for the electrochemical evaluation of antioxidant properties of some metal complex, despite no systematic study was performed to show by mean of electrochemistry, the interactions between DPPH and the compounds tested …”

Section: Introductionmentioning

confidence: 99%

Electrochemistry of 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) in Acetonitrile in Presence of Ascorbic Acid ‐ Application for Antioxidant Properties Evaluation

et al. 2019

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The electrochemistry of 2,2-diphenyl-1-picrylhydrazyl (DPPH) in acetonitrile was studied in presence of ascorbic acid (AAH 2 ) as model antioxidant. In the presence of AAH 2 , the intensities of the two characteristic systems of DPPH decreases and an intense oxidation peak at 1.07 V assigned to the oxidation of reduced DPPH was observed. The currents associated to these electrochemical processes showed excellent correlation with the amount of AAH 2 added and were used for determining its free radicals scavenger activity. Chronoamperometry was found more suitable for a real time monitoring of the chemical reaction between DPPH and an antioxidant, and thus to evaluate their efficiencies by determining the corresponding half-maximal inhibitory concentration (IC 50 ) values. Comparison of the reactivity of the antioxidants tested was possible by comparing the times necessary for the stabilization of the residual DPPH reduction currents. The method was subsequently applied to the evaluation of antioxidant properties of lemon and orange samples.[a] Dr.

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“…In an interesting study, Nakanishi et al reported that the vitamin E scavengers DPPH radicals via the SET–PT mechanism in methanol. Suggesting the role of the electron transfer mechanism in the scavenger DPPH radicals and its contribution with the HAT process.…”

Section: Resultsmentioning

confidence: 99%

The antioxidant activity of 4‐hydroxycoumarin derivatives and some sulfured analogs

Rouaiguia-Bouakkaz

Benayahoum

2015

J of Physical Organic Chem

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In this work, the relationship between the structure and the radical scavenging activity of seven hydroxycoumarins and their sulfured analogs was investigated for the first time by density functional theory calculation in the gas phase, benzene, and water. Our investigation includes hydrogen atom transfer, single-electron transfer-proton transfer, and sequential proton loss electron transfer mechanisms. The results revealed that the bond dissociation enthalpy values of sulfured coumarins were lower than those of hydroxylated analogs. The obtained results were in a good agreement with the experimental results. The hydrogen atom transfer mechanism is dominant in both benzene and vacuum. The sequential proton loss electron transfer mechanism represents the most thermodynamically preferred reaction pathway in water. However, single-electron transfer-proton transfer mechanism is not the most preferred one in all media. Finally, this work contributes to the understanding of the pharmacological activity of the compounds studied.

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Electron-transfer mechanism in radical-scavenging reactions by a vitamin E model in a protic medium

Cited by 113 publications

References 21 publications

Radical scavenging activity of sterically hindered catecholate and o-amidophenolate complexes of LSbVPh3 type

Radical scavenging activity of sterically hindered catecholate and o-amidophenolate complexes of LSbVPh3 type

Electrochemistry of 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) in Acetonitrile in Presence of Ascorbic Acid ‐ Application for Antioxidant Properties Evaluation

The antioxidant activity of 4‐hydroxycoumarin derivatives and some sulfured analogs

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