On the free radical scavenging and metallic ion chelating activities of pyridoxal - Could the pro-oxidant risk be competitive?

Ngo, Thị Chinh; Truong, Dinh Hieu; Nguyen, Thi Thuy Nga; Quang, Duong Tuan; Dao, Duy Quang

doi:10.1016/j.phytochem.2022.113176

Cited by 5 publications

(7 citation statements)

References 72 publications

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“…From the values of the kinetic constants, it can be seen that the formation of complexes promotes the process of copper reduction towards lower oxidation states. In general, we can support the fact that the presence of ascorbic acid causes a greater pro-oxidant hazard than the reaction with the superoxide radical does, as previously noted for other antioxidants ( Ngo et al, 2022 ).…”

Section: Resultssupporting

confidence: 88%

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Computational investigation on the antioxidant activities and on the Mpro SARS-CoV-2 non-covalent inhibition of isorhamnetin

et al. 2023

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In the present work, we report a computational study on some important chemical properties of the flavonoid isorhamnetin, used in traditional medicine in many countries. In the course of the study we determined the acid-base equilibria in aqueous solution, the possible reaction pathways with the •OOH radical and the corresponding kinetic constants, the complexing capacity of copper ions, and the reduction of these complexes by reducing agents such as superoxide and ascorbic anion by using density functional level of theory Density Functional Theory. Finally, the non-covalent inhibition ability of the SARS-CoV-2 main protease enzyme by isorhamnetin was examined by molecular dynamics (MD) and docking investigation.

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Section: Resultssupporting

confidence: 88%

“…In all the studied systems, the reaction with the superoxide is more exergonic than the corresponding one with the ascorbic acid anion, as also noted previously for the pyridoxal antioxidant (Ngo et al, 2022).…”

Section: Reduction Mechanism With Osupporting

confidence: 83%

Computational investigation on the antioxidant activities and on the Mpro SARS-CoV-2 non-covalent inhibition of isorhamnetin

et al. 2023

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“…37,38 ] + were employed as a recommendation by previous works. [38][39][40][41][42] The high-spin states of hydrated Fe(II) and Fe(III) ions in this study were equal to 5 and 6, respectively. 23,38,41,[43][44][45][46] The kinetics of the HO-initiated oxidation of Pro, which occurs as FHT reactions in water, were studied using the pre-reactive complexes scheme proposed by Singleton and Cvetanovic 47 .…”

Section: Methodsmentioning

confidence: 60%

“…Indeed, several previous studies show that some organic molecules exhibit the reactive HO  radical via the Fenton-like reactions of their transition metal ion complexes. 23,[38][39][40][41][42] The formed HO  radicals have a high potential to return oxidizing the Pro amino acid. The whole phenomenon is called the prooxidant risk of an organic molecule.…”

Section: Indirect Enhancementmentioning

confidence: 99%

Influence of transition metal ions on the oxidation of L-proline amino acid initiated by HO● radical in the aqueous phase

Dao

Truong

Nguyen

2022

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The oxidation of L-proline (Pro) amino acid by HO • radical and the influence of transition metal ions on this process have been investigated by using the density functional theory (DFT) method at the M05-2X/6-311++G(3df,3pd)//M05-2X/6-311++G(d,p) level of theory in the aqueous phase. The results show that Pro can be oxidized by HO • radical via formal hydrogen transfer (FHT) reactions at multiple sites, with the highest branching ratio found at hydrogen atoms H10 (30.04%) and H12 (25.60%). The overall rate constant at 298.15K is determined as 6.04 × 10 8 M -1 s -1 , and its expression from 250 to 400K is k=1.634×T 2.990 ×exp[1.591(kcal mol -1 )/RT] M -1 s -1 . In addition, Pro tends to form the stable mono-and bidentate complexes with both Fe and Cu ions via the-COO functional group of dipole-salt form, which significantly increases when the concentration of Pro doubles. The most stable Cu(II)-Pro complexes have high potential oxidant risks by enhancing the HO • radical formation when reducing agents such as superoxide anion, or ascorbate anion are available. Besides, the oxidant reaction of the high oxidation state complexes, including Fe(III)-Pro and Cu(II)-Pro, by HO • radical as FHT reactions have a lower rate constant than that of free-ligand, while the ones for SET reactions is extremely low even though they are higher than that of free-ligand. As a result, the Pro's oxidation enhancement of these complexes is negligible. In contrast, the rate constants of SET reactions of low oxidation state complexes (i.e., Fe(II)-Pro and Cu(I)-Pro) are likely to be many times faster than the oxidation rate of free ligand, and thus, these complexes promote the oxidation of Pro. Finally, the FHT chemical nature of HO-initiated oxidation for free Pro, Fe(III)-Pro, and Cu(II)-Pro complexes are evaluated to determine whether these processes occur via hydrogen atom transfer (HAT) or proton-coupled electron transfer (PCET).

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“…The M05-2X functional has largely been chosen by several similar kinetic studies related to the complexes of transition metal and an organic ligand [23,[39][40][41]. The influence of the aqueous media was mimicked using the solvation model based on the quantum mechanical charge density of a solute molecule interacting with a continuum description of the solvent (SMD) [42][43][44], which has also been widely used in the literature [39,41] [40,41,[45][46][47]. The high-spin states of hydrated Fe(II) and Fe(III) ions in this study were equal to 5 and 6, respectively [23,41,46,[48][49][50][51].…”

Section: Methodsmentioning

confidence: 99%

Revisiting the HO ^● -initiated oxidation of L-proline amino acid in the aqueous phase: influence of transition metal ions

2023

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The oxidation of L-proline (Pro) by HO ● radical in water and the influence of transition metal ions on this process has been revisited by using the density functional theory (DFT) method at the M05-2X/6-311 + + G(3df,3pd)//M05-2X/6-311 + + G(d,p) level of theory at the temperature of 298.15 K. The main reactive sites of the HO ● –initiated oxidation of Pro via hydrogen atom transfer (HAT) reactions are at the β- and γ-carbon, with the branching ratios being 44.6% and 39.5%, respectively. The overall rate constant at 298.15 K is 6.04 × 10 8 M −1 s −1 . In addition, Pro tends to form stable complexes with both Fe and Cu ions via the –COO functional group of dipole-salt form. The most stable Cu(II)-Pro complexes have high oxidant risks in enhancing the HO ● formation in the presence of reducing agents. Besides this, the high oxidation state metal complexes, i.e. Fe(III)-Pro and Cu(II)-Pro, may be oxidized by HO ● radical via HAT reactions but with a lower rate constant than that of free-Pro. By contrast, the low oxidation state metal complexes (i.e. Fe(II)-Pro and Cu(I)-Pro) have higher oxidation risks than the free ligands, and thus, the complexation enhances the oxidation of Pro amino acid.

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On the free radical scavenging and metallic ion chelating activities of pyridoxal - Could the pro-oxidant risk be competitive?

Cited by 5 publications

References 72 publications

Computational investigation on the antioxidant activities and on the Mpro SARS-CoV-2 non-covalent inhibition of isorhamnetin

Computational investigation on the antioxidant activities and on the Mpro SARS-CoV-2 non-covalent inhibition of isorhamnetin

Influence of transition metal ions on the oxidation of L-proline amino acid initiated by HO● radical in the aqueous phase

Revisiting the HO ^● -initiated oxidation of L-proline amino acid in the aqueous phase: influence of transition metal ions

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On the free radical scavenging and metallic ion chelating activities of pyridoxal - Could the pro-oxidant risk be competitive?

Cited by 5 publications

References 72 publications

Computational investigation on the antioxidant activities and on the Mpro SARS-CoV-2 non-covalent inhibition of isorhamnetin

Computational investigation on the antioxidant activities and on the Mpro SARS-CoV-2 non-covalent inhibition of isorhamnetin

Influence of transition metal ions on the oxidation of L-proline amino acid initiated by HO● radical in the aqueous phase

Revisiting the HO ● -initiated oxidation of L-proline amino acid in the aqueous phase: influence of transition metal ions

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Revisiting the HO ^● -initiated oxidation of L-proline amino acid in the aqueous phase: influence of transition metal ions