Thermodynamic study of vitamin B6 antioxidant potential

Škorňa, Peter; Rimarčík, Ján; Poliak, Peter; Lukeš, Vladimı́r; Klein, Erik

doi:10.1016/j.comptc.2015.10.010

Cited by 24 publications

(14 citation statements)

References 43 publications

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“…However, for mono-substituted phenols and tocopherols, we have confirmed that employed computational approach provides results in agreement with available experimental data (Klein, 2006;Klein, 2007). Though individual BDE values may be slightly underestimated, the trends are in very good agreement with experimental data and theoretical results obtained using newer functionals developed for reaction energetics calculations (Đorović, 2014(Đorović, , Marković, 2012Škorňa, 2016). For gas-phase PA values of mono-substituted phenols, employed computational method provided results in excellent agreement with experimental results (Klein, 2006).…”

Section: Reaction Enthalpies For Carboxylate Anion Of Gallic Acidsupporting

confidence: 85%

“…In last years, newer M05-2X and M06-2X functional with SMD solvation model are also applied in the thermodynamics of antioxidant action works -including the reactions of gallic acid with various free radicals (Đorović, 2014). These provide identical trends in BDE, IP, PDE, PA and ETE, although a shift in the absolute values obtained using different functional and/or solvation model can be observed (Marković, 2013;Škorňa, 2016;Marković, 2016;Michalík, 2015). For ortho-, meta-, and para-substituted hydroxybenzoic acids, it was found that the shift in calculated proton affinities can be attributed mainly to the employed solvation model (Michalík, 2015) -values obtained using B3LYP and M06-2X functionals with the same solvation models were in very good mutual agreement, while application of SMD model led to PA values lower by ca 80 kJ mol -1 in comparison to those obtained from IEF-PCM calculations.…”

Section: Introductionmentioning

confidence: 77%

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Gallic acid: thermodynamics of the homolytic and heterolytic phenolic O—H bonds splitting-off

Škorňa

Michalík

Klein

2016

Acta Chimica Slovaca

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The DFT study of primary antioxidant action of gallic acid and its carboxylic anion is presented in the gas-phase, benzene and water. Corresponding reaction enthalpies for three possible mechanisms was calculated using B3LYP/6-311++G** method. Bond dissociation enthalpy (BDE) and proton dissociation enthalpy (PDE) of 4-OH group was found to be the lowest in gas-phase as well as in both solvents approximated by IEF-PCM model. Ionization potentials (IPs) were higher than BDEs in all cases. Deprotonation of carboxylic group result in increased antioxidant potency as drop in BDE, proton affinities (PAs) and IPs was indicated in all environments.

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Section: Reaction Enthalpies For Carboxylate Anion Of Gallic Acidsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 77%

Gallic acid: thermodynamics of the homolytic and heterolytic phenolic O—H bonds splitting-off

Škorňa

Michalík

Klein

2016

Acta Chimica Slovaca

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“…Subsequent theoretical studies carried out by Matxain and coworkers showed that PN, another form of vitamin B 6 , is highly reactive towards singlet oxygen [77] and hydroxyl radicals [28,29] but not against superoxide [28]. The transfer of the phenolic hydrogen atom could contribute significantly to this antioxidant activity [78], in perfect agreement with our findings. Furthermore, a recent study showing that PM reduces the levels of intracellular ROS induced by the glycation of the human serum albumin protein, further supports the idea that PM is a powerful antioxidant [79].…”

Section: Discussionsupporting

confidence: 91%

How Does Pyridoxamine Inhibit the Formation of Advanced Glycation End Products? The Role of Its Primary Antioxidant Activity

et al. 2019

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Pyridoxamine, one of the natural forms of vitamin B 6 , is known to be an effective inhibitor of the formation of advanced glycation end products (AGEs), which are closely related to various human diseases. Pyridoxamine forms stable complexes with metal ions that catalyze the oxidative reactions taking place in the advanced stages of the protein glycation cascade. It also reacts with reactive carbonyl compounds generated as byproducts of protein glycation, thereby preventing further protein damage. We applied Density Functional Theory to study the primary antioxidant activity of pyridoxamine towards three oxygen-centered radicals (•OOH, •OOCH 3 and •OCH 3 ) to find out whether this activity may also play a crucial role in the context of protein glycation inhibition. Our results show that, at physiological pH, pyridoxamine can trap the •OCH 3 radical, in both aqueous and lipidic media, with rate constants in the diffusion limit (>1.0 × 10 8 M −1 s −1 ). The quickest pathways involve the transfer of the hydrogen atoms from the protonated pyridine nitrogen, the protonated amino group or the phenolic group. Its reactivity towards •OOH and •OOCH 3 is smaller, but pyridoxamine can still scavenge them with moderate rate constants in aqueous media. Since reactive oxygen species are also involved in the formation of AGEs, these results highlight that the antioxidant capacity of pyridoxamine is also relevant to explain its inhibitory role on the glycation process.Given the pathological implications of protein glycation, the design of molecules with the ability to attenuate its effects is a matter of utmost concern. The three main mechanisms by which these molecules, known as protein glycation inhibitors, prevent the formation of AGEs are: (i) the complexation of metal ions that catalyze the secondary reactions of protein glycation; (ii) the scavenging of RCS; and (iii) ROS generated as byproducts of those secondary reactions. In 1999, it was discovered that pyridoxamine (PM) had the ability of inhibiting the oxidation of Amadori compounds to form AGEs [10]. PM is one of the three natural forms of vitamin B 6 , together with pyridoxal (PL) and pyridoxine (PN). By that time, it was known that PM was very reactive towards carbonyl groups, since it acted as a coenzyme in transamination reactions between carbonyl compounds and amino groups [11], and this led to consider that it could be an effective AGE inhibitor. Thus far, several studies in both animal and human models have shown its therapeutic effects on diabetic kidney disease [12,13], as well as on retinopathies [14] and vascular diseases [15].Concerning its mechanism of action, it has been suggested that PM could be effective as a metal chelating agent, a RCS scavenger and/or a ROS scavenger. It can form stable complexes with Cu 2+ and Fe 3+ [16,17] and stable adducts with several dicarbonyl compounds [18][19][20][21], as well as inhibit the production of the hydroxyl radical from the Fenton reaction or directly react with it [22][23][24]. Some studies also suggest that ...

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“…These antioxidants may also have potential to protect against a number of disease conditions such as aging, atherosclerosis, cancer, autoimmune conditions, asthma, and arthritis. Some vitamins (vitamin C and vitamin B6) have been often been reported as antioxidants which have the capability to limit the oxidative damage in humans and lower the risk of certain chronic diseases [6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Antioxidant Potential of Selected Dietary Vitamins; Computational Insights

Pandithavidana

Jayawardana

2019

Molecules

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Density functional theory (DFT) was used to explore the antioxidant properties of some naturally occurring dietary vitamins, and the reaction enthalpies related to various mechanisms of primary antioxidant action, i.e., hydrogen atom transfer, single electron transfer–proton transfer, and sequential proton loss–electron transfer were discussed in detail. B3LYP, M05-2X, and M06-2X functionals were utilized in this work. For aqueous phase studies, the integral equation formalism polarized continuum model (IEF–PCM) was employed. From the outcomes, hydrogen atom transfer (HAT) was the most probable mechanism for the antioxidant action of this class of compounds. Comparison of found results with experimental data (available in literature), vitamin C possesses the lowest enthalpy values for both proton affinity (PA) and bond dissociation energy (BDE)in the aqueous phase, suggesting it as the most promising candidate as an antioxidant. Accordingly, these computational insights encourage the design of structurally novel, simple vitamins which will be more economical and beneficial in the pharmaceutical industry.

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Thermodynamic study of vitamin B6 antioxidant potential

Cited by 24 publications

References 43 publications

Gallic acid: thermodynamics of the homolytic and heterolytic phenolic O—H bonds splitting-off

Gallic acid: thermodynamics of the homolytic and heterolytic phenolic O—H bonds splitting-off

How Does Pyridoxamine Inhibit the Formation of Advanced Glycation End Products? The Role of Its Primary Antioxidant Activity

Comparative Study of Antioxidant Potential of Selected Dietary Vitamins; Computational Insights

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