Reactivity of flavonoids toward superoxide radical: An electrochemical approach

Jadreško, Dijana; Miličević, Ante; Jovanović, Ivana

doi:10.1016/j.electacta.2022.140501

Cited by 10 publications

(15 citation statements)

References 45 publications

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“…On the other hand, significant distortion of the CVs shape can occur after the addition of the plant extracts, which complicates the calculation of the superoxide scavenging capacity and makes the data unreliable. Furthermore, phenolic antioxidants of various natures change oxygen electroreduction CVs in a different way (appearance of cathodic pre-peak and/or one or more broad anodic post-peaks) depending on the structure of the phenolic compound [104,105]. Similar effects can be obtained in the case of medicinal plant samples [102].…”

Section: Methods Based On the Reactions Of Antioxidants With Radicalsmentioning

confidence: 72%

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Ziyatdinova

Kalmykova

2023

Molecules

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Medicinal plants are an important source of bioactive compounds with a wide spectrum of practically useful properties. Various types of antioxidants synthesized in plants are the reasons for their application in medicine, phytotherapy, and aromatherapy. Therefore, reliable, simple, cost-effective, eco-friendly, and rapid methods for the evaluation of antioxidant properties of medicinal plants and products on their basis are required. Electrochemical methods based on electron transfer reactions are promising tools to solve this problem. Total antioxidant parameters and individual antioxidant quantification can be achieved using suitable electrochemical techniques. The analytical capabilities of constant-current coulometry, potentiometry, various types of voltammetry, and chrono methods in the evaluation of total antioxidant parameters of medicinal plants and plant-derived products are presented. The advantages and limitations of methods in comparison to each other and traditional spectroscopic methods are discussed. The possibility to use electrochemical detection of the antioxidants via reactions with oxidants or radicals (N- and O-centered) in solution, with stable radicals immobilized on the electrode surface, via oxidation of antioxidants on a suitable electrode, allows the study of various mechanisms of antioxidant actions occurring in living systems. Attention is also paid to the individual or simultaneous electrochemical determination of antioxidants in medicinal plants using chemically modified electrodes.

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Section: Methods Based On the Reactions Of Antioxidants With Radicalsmentioning

confidence: 72%

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Ziyatdinova

Kalmykova

2023

Molecules

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“…The mechanistic role that these polyphenols play is the subject of many studies. For instance, a recent electrochemical study among flavonoids (AH) and superoxide itemized most of the cyclic voltammetry interactions using the following Equations (1)–(4) [ 10 ]. O 2 + e − → O 2 • − O 2 • − + AH → HO 2 − + A• HO 2 − + AH → H 2 O 2 + A − A• → nonradical products Overall reaction: O 2 + e − + 2AH → H 2 O 2 + A − + non-radical products.…”

Section: Introductionmentioning

confidence: 99%

“…Compared to the classical voltaic cell arrangement, which has only one electrode, this alternative electrochemical system allows for a better treatment of data when analyzing polyphenol-related scavenging [ 11 ]. In our studies, the combination of computational density functional theory (DFT) and experimental cyclic voltammetry reveals the formation of H 2 O 2 after scavenging of superoxide by several common polyphenols, including the commercially utilized antioxidant BHT [ 12 ] and clovamide, an antioxidant component of chocolate [ 10 , 13 ]. Indeed, DFT studies allowed us to also describe the formation of a molecule of O 2 along with H 2 O 2 [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Aromatic Polyphenol π-π Interactions with Superoxide Radicals Contribute to Radical Scavenging and Can Make Polyphenols Mimic Superoxide Dismutase Activity

Caruso

Incerpi

Pedersen

et al. 2022

CIMB

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Polyphenols are valuable natural antioxidants present in our diet that likely mitigate aging effects, neurodegenerative conditions, and other diseases. However, because of their poor absorption in the gut and consequent low concentration in biological fluids (µM range), reservations about polyphenol antioxidant efficiency have been raised. In this review, it is shown that after scavenging superoxide radicals, coumarin, chalcone, and flavonoid polyphenols can reform themselves, becoming ready for additional cycles of scavenging, similar to the catalytic cycle in superoxide dismutase (SOD) action. The π-π interaction between one polyphenol ring and superoxide is associated with oxidation of the latter due to transfer of its unpaired electron to a polyphenolic aromatic ring, and consequent formation of a molecule of O2 (one product of SOD action). Mechanistically, it is very difficult to establish if this π-π interaction proceeds before or after the most common mode of scavenging superoxide, e.g., abstraction of an aromatic polyphenol H(hydroxyl), which then is used to form H2O2 (the other molecule produced by SOD action). At the end of this cycle of superoxide scavenging, 4-methyl-7,8-di-hydroxy-coumarin and the flavonoid galangin reform themselves. An alternative mechanistic pathway by galangin forms the η-(H2O2)-galangin-η-O2 complex that includes additional H2O2 and O2 molecules. Another mode of action is seen with the chalcone butein, in which the polyphenol system incorporates a molecule of O2, e.g., a η-O2-butein complex is formed, ready for additional scavenging. Of the several families of polyphenols analyzed in this review, only butein was able to circumvent an initial π-π interaction, directing the superoxide towards H(hydroxyl) in position 4, e.g., acting as a typical polyphenol scavenger of superoxide. This fact did not impede an additional superoxide to later react with the aromatic ring in π-π fashion. It is concluded that by mimicking SOD enzyme action, the low concentration of polyphenols in biological fluids is not a limiting factor for effective scavenging of superoxide.

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“…Therefore, the antioxidant activity (AA) of flavonoids and the theoretical models for its prediction, along with mechanisms of flavonoids action, are of particular interest to science. Research papers dealing with these issues frequently attempt to establish a mathematical connection between AA and the first electrochemical oxidation potential, E p1 , of the flavonoids, with more or less success ( 10 - 17 ). Our team strives to develop a comprehensive model for the estimation of the E p1 based on the electronic structure and its changes during electrochemical oxidation ( 18 - 23 ).…”

mentioning

confidence: 99%

“… a ref( 17 ), b ref 20), c ref( 21 ), d ref( 25 ) e ref( 26 ), f ref( 27 ), g ( 22 ), h ( 23 ), i ( 18 ) …”

mentioning

confidence: 99%

Estimating flavonoid oxidation potentials: mechanisms and charge-related regression models

Miličević

2023

Archives of Industrial Hygiene and Toxicology

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In this paper, I tested our quadratic regression models for the estimation of flavonoid oxidation potentials based on spin populations, the differences in the net atomic charges between a cation and a neutral flavonoid, between a radical and an anion of a flavonoid, and between a radical and a neutral flavonoid on a larger set of flavonoids (N = 35). By including six new flavonoids (5,6,7-trihydroxyflavone, 3,3’,4’,7-tetrahydroxyflavone, 3,7-dihydroxyflavone, 4’,7-dihydroxyflavone, 4’,5,7-trihydroxyisoflavone, and 6-hydroxyflavone), we created a respectable calibration set of 35 flavonoids with their oxidation potentials all measured at the same conditions by the same experimentalist. The best model was based on the mean values of the three variables using differences in the net atomic charges (R 2 = 0.970, S.E. = 0.043), which are connected with the three different mechanisms of electrochemical oxidation, SET-PT, SPLET, and HAT.

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Reactivity of flavonoids toward superoxide radical: An electrochemical approach

Cited by 10 publications

References 45 publications

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Aromatic Polyphenol π-π Interactions with Superoxide Radicals Contribute to Radical Scavenging and Can Make Polyphenols Mimic Superoxide Dismutase Activity

Estimating flavonoid oxidation potentials: mechanisms and charge-related regression models

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