Examining the reaction between antioxidant compounds and 2,2-diphenyl-1-picrylhydrazyl (DPPH) through a computational investigation

Maciel, Eduardo Nunes; Almeida, Shawan K. C.; Silva, Sebastião C. da; Souza, Gabriel L. C. de

doi:10.1007/s00894-018-3745-1

Cited by 32 publications

(9 citation statements)

References 53 publications

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“…The fact that a hydrogen atom carries an electron makes HAT a redox-based antioxidant mechanism. Typically, DPPH•-scavenging determination in alcoholic solutions can be used to examine the HAT of a phenolic antioxidant [35,36,37].…”

Section: Resultsmentioning

confidence: 99%

Antioxidant Mechanisms of Echinatin and Licochalcone A

Liang

Ouyang

et al. 2018

Molecules

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Echinatin and its 1,1-dimethyl-2-propenyl derivative licochalcone A are two chalcones found in the Chinese herbal medicine Gancao. First, their antioxidant mechanisms were investigated using four sets of colorimetric measurements in this study. Three sets were performed in aqueous solution, namely Cu2+-reduction, Fe3+-reduction, and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-scavenging measurements, while 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging colorimetric measurements were conducted in methanol solution. The four sets of measurements showed that the radical-scavenging (or metal-reduction) percentages for both echinatin and licochalcone A increased dose-dependently. However, echinatin always gave higher IC50 values than licochalcone A. Further, each product of the reactions of the chalcones with DPPH• was determined using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS). The UPLC-ESI-Q-TOF-MS/MS determination for echinatin yielded several echinatin–DPPH adduct peaks (m/z 662, 226, and 196) and dimeric echinatin peaks (m/z 538, 417, and 297). Similarly, that for licochalcone A yielded licochalcone A-DPPH adduct peaks (m/z 730, 226, and 196) and dimeric licochalcone A peaks (m/z 674 and 553). Finally, the above experimental data were analyzed using mass spectrometry data analysis techniques, resonance theory, and ionization constant calculations. It was concluded that, (i) in aqueous solution, both echinatin and licochalcone A may undergo an electron transfer (ET) and a proton transfer (PT) to cause the antioxidant action. In addition, (ii) in alcoholic solution, hydrogen atom transfer (HAT) antioxidant mechanisms may also occur for both. HAT may preferably occur at the 4-OH, rather than the 4′-OH. Accordingly, the oxygen at the 4-position participates in radical adduct formation (RAF). Lastly, (iii) the 1,1-dimethyl-2-propenyl substituent improves the antioxidant action in both aqueous and alcoholic solutions.

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Section: Resultsmentioning

confidence: 99%

Antioxidant Mechanisms of Echinatin and Licochalcone A

Liang

Ouyang

et al. 2018

Molecules

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“…From literature, there have been three known mechanisms HAT (H-atom Transfer), SET-PT (Single electron transfer-proton transfer), and SPLET (Sequential proton loss electron transfer), which concern radical-scavenging properties of the parent molecular (Flav-OH) [11][12][13][14][15][16][17]:…”

Section: Eoretical Parameters and Computational Procedurementioning

confidence: 99%

Isoflavones and Isoflavone Glycosides: Structural-Electronic Properties and Antioxidant Relations—A Case of DFT Study

Son

Van

2019

Journal of Chemistry

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Isoflavonoids and isoflavonoid glycosides have drawn much attention because of their antioxidant radical-scavenging capacity. Based on computational methods, we now present the antioxidant potential results of genistein (1), biochanin A (2), ambocin (3), and tectorigenin 7-O-[β-D-apiofuranosyl-(1-6)-β-D-glucopyranoside] (4). e optimized structures of the neutral and radical forms have been determined by the DFT-B3LYP method with the 6-311G(d) basis set. From the findings and thermodynamic point of view, the ring B system of isoflavones is considered as an active center in facilitating antioxidant reactions. Antioxidant activities are mostly driven by O-H bond dissociation enthalpy (BDE) following hydrogen atom transfer (HAT) mechanism. Antioxidant ability can be arranged in the following order: compounds (4) > (3) > (2) > (1). Of comprehensive structural analysis, flavonoids with 4′-methylation and 6-methoxylation, especially 7-glycosylation would claim responsibility for antioxidant enhancement.

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“…It is widely known that the antioxidant activity of a given polyphenol is based on its capability of scavenging free radicals [17]. Moreover, this feature can be successfully probed through the examination of energetic properties that are related to some specific reaction mechanisms [18][19][20][21]. For example, the O-H bond dissociation enthalpies (BDEs) are directly associated to the hydrogen atom transfer (HAT) mechanism [22,23].…”

Section: Introductionmentioning

confidence: 99%

Probing structural properties and antioxidant activity mechanisms for eleocarpanthraquinone

et al. 2020

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In this work, we present a computational investigation on the structure and energetics of eleocarpanthraquinone, a newly isolated polyphenolic anthrone-antraquinone. Properties such as bond lengths, angles, atomic charges, bond dissociation enthalpies (BDEs), and ionization potential (IP) were determined through the use of density functional theory (DFT). The B3LYP and M06-2X exchange-correlation functionals were employed along with the 6-31+G(d,p), 6-31++G(d,p), and 6-311+G(d,p) basis sets for performing computations in the gas-phase, water, methanol, and ethanol. The conformation presenting all the hydroxyl groups undergoing hydrogen-bond interactions with neighboring oxygen atoms (conformation 5) was assigned as the most stable structure while its counterpart presenting no hydrogen-bond interaction was found to be 36.45 kcal/mol less stable than conformation 5 in the potential energy surface probed at the B3LYP/6-311+G(d,p) level of theory in the gas-phase, for instance. More importantly, the lowest O-H bond dissociation enthalpy was determined to be 93.80 kcal/mol at the B3LYP/6-311+G(d,p) level of theory in water against the 146.58 kcal/mol regarding the IP computed at the same approach, suggesting the hydrogen atom transfer mechanism as being preferred over the single electron transfer mechanism in regards to the antioxidant potential for the case of eleocarpanthraquinone; the same conclusion was drawn from the outcomes of all the other approaches used.

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Examining the reaction between antioxidant compounds and 2,2-diphenyl-1-picrylhydrazyl (DPPH) through a computational investigation

Cited by 32 publications

References 53 publications

Antioxidant Mechanisms of Echinatin and Licochalcone A

Antioxidant Mechanisms of Echinatin and Licochalcone A

Isoflavones and Isoflavone Glycosides: Structural-Electronic Properties and Antioxidant Relations—A Case of DFT Study

Probing structural properties and antioxidant activity mechanisms for eleocarpanthraquinone

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