Free radical scavenging potency of quercetin catecholic colonic metabolites: Thermodynamics of 2H+/2e− processes

Amić, Ana; Lučić, Bono; Stepanić, Višnja; Marković, Zoran; Marković, Svetlana; Marković, Jasmina M. Dimitrić; Amić, Dragan

doi:10.1016/j.foodchem.2016.09.018

Cited by 94 publications

(53 citation statements)

References 39 publications

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“…The second H-atom abstraction from -COOH group, which is less energy demanding than the first one by 25.59 kcal/mol (61.56 kcal/mol vs 87.15 kcal/mol), gives dienone lactone (Figure 4). Lower energetic costs of second processes, which indicate 2H + /2e -processes as plausible, have been recognized earlier in the case of guaiacyl moiety, [49] catechol moiety [27,29] and uric acid. [28] Because the scavenging processes are highly influenced by the properties of the scavenged radical species, we also calculated the free energy of reactions (rG o ) of phloretic acid with each of ten selected radicals ( • OH, • Table 2 and Table 3, respectively.…”

Section: Resultssupporting

confidence: 54%

“…It is equal to the total energy Figure 5, where overall energy requirements for scavenging of selected radicals via dHAT, dET-PT and SdPLdET are depictured, phloretic acid has potential to effectively scavenge hydroxyl, alkoxyl, phenoxyl, peroxyl and superoxide radicals (in descending order). As in the case of catecholic compounds, [29] 2H + /2e -mechanisms are less energy demanding in polar solvents. Obviously, here presented thermodynamic parameters may be important factors governing the radical scavenging reactions of phloretic acid, while a more complete understanding would require kinetic analysis.…”

Section: Resultsmentioning

confidence: 99%

“…[24,32] To investigate radical scavenging potential of phloretic acid we used the same set of radicals as in our recent papers. [29,30] It embraces oxygen-derived radicals with very different characteristics:…”

Section: Computational Detailsmentioning

confidence: 99%

“…[25] However, depending on a number and position of radical scavenging moieties such as phenolic O-H and imino N-H groups, they may also proceed as double (multiple) sequential 1H + /1e -mechanisms. [26][27][28][29] Recently, we have performed a DFT investigation of radical scavenging potency of phloretic acid by considering single 1H + /1e -mechanisms related to homolytic and heterolytic O-H bond cleavage in phenolic OH group. [30] In this study, we have computationally investigated energetics of double, i.e., 2H + /2e -mechanisms (two sequential 1H + /1e -processes) by including carboxyl group of phloretic acid in consideration.…”

Section: Introductionmentioning

confidence: 99%

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Carboxyl Group as a Radical Scavenging Moiety: Thermodynamics of 2H+/2e– Processes of Phloretic Acid

Amić¹,

Lučić²,

Marković³

et al. 2016

Croat. Chem. Acta

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Phloretic acid is one of the most abundant colon catabolites of various classes of polyphenols (e.g., polymeric proanthocyanidins, tea catechins, and ellagitannins). In this paper thermodynamics of 2H + /2e -radical scavenging mechanisms of phloretic acid was studied. For the first time the involvement of carboxyl group in double hydrogen atom transfer (dHAT), double electron transfer-proton transfer (dET-PT) and sequential double proton loss double electron transfer (SdPLdET) processes was investigated. Obtained results indicate that phloretic acid possesses potential for inactivating radicals of different characteristics (HO• etc.) via dHAT and SdPLdET mechanisms. Because phloretic acid is usually better absorbed than its precursor molecules, it may contribute to health benefits associated with regular intake of polyphenol-rich diet by direct scavenging of radicals.

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Section: Resultssupporting

confidence: 54%

Section: Resultsmentioning

confidence: 99%

Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Carboxyl Group as a Radical Scavenging Moiety: Thermodynamics of 2H+/2e– Processes of Phloretic Acid

Amić¹,

Lučić²,

Marković³

et al. 2016

Croat. Chem. Acta

Self Cite

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“…As known, quercetin exists in the anionic form at pH>9 and easily detaches electron giving phenoxide anion‐radical undergoing second electron detachment with formation of o‐quinone fragment in B‐ring (Scheme ) that agrees well with the reported earlier .…”

Section: Resultsmentioning

confidence: 99%

Polyquercetin/MWNT‐modified Electrode for the Determination of Natural Phenolic Antioxidants

2017

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Novel highly sensitive voltammetric method for the gallic acid, catechin and epigallocatechin gallate (EGCG) quantification has been developed using glassy carbon electrode modified with multi‐walled carbon nanotubes and polyquercetin (polyquercetin/MWNT/GCE). The effect of electropolymerization parameters (number of cycles, monomer concentration and polarization window) on the electrode characteristics has been evaluated. The electrode surface has been characterized with SEM, CV and EIS. The linear dynamic ranges of 0.50–10 and 10–750 μM for gallic acid, 0.10–10 and 10.0–250 μM for catechin and 0.050–10 and 10–100 μM for EGCG have been obtained in differential pulse mode with the detection limits of 0.10, 0.024 and 0.014 μM, respectively. The approach has been successfully applied for the tea antioxidant capacity evaluation (AOC). The positive correlations with antioxidant activity towards DPPH• and total phenolics (r=0.7845 and 0.7658 at rcrit=0.4227, n=22) have been obtained.

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Biosynthesis of bioactive tamarixetin in recombinant Escherichia coli

Darsandhari

Dhakal

Shrestha

et al. 2020

Biotech and App Biochem

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Tamarixetin, a monomethylated derivative of quercetin, has been reported to possess many important biological activities.In the present study, a whole cell biotransformation system was used for regiospecific methylation of quercetin to produce 4 -O-methylated quercetin (tamarixetin) using methyltransferase from Streptomyces sp. KCTC 0041BP in Escherichia coli Bl21 (DE3). Its production was enhanced by adding a plasmid containing S-adenosine-L-methionine (SAM) synthase from E. coli K12 (MetK) with subsequent feeding of L-methionine and glycerol in the culture. The best condition produced ∼279 μM (88.2 mg/L) of tamarixetin. The biological activity of tamarixetin was tested and compared with quercetin, 7-O-methylated quercetin, and 3-O-methylated quercetin. Results showed that the growth of all tested cancer cell lines (AGS, B16F10, C6, and HeLa) were inhibited by tamarixetin more effectively than other methylated derivatives of quercetin or quercetin. Tamarixetin also exhibited the best antimelanogenic activity among all compounds tested.

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Free radical scavenging potency of quercetin catecholic colonic metabolites: Thermodynamics of 2H+/2e− processes

Cited by 94 publications

References 39 publications

Carboxyl Group as a Radical Scavenging Moiety: Thermodynamics of 2H+/2e– Processes of Phloretic Acid

Carboxyl Group as a Radical Scavenging Moiety: Thermodynamics of 2H+/2e– Processes of Phloretic Acid

Polyquercetin/MWNT‐modified Electrode for the Determination of Natural Phenolic Antioxidants

Biosynthesis of bioactive tamarixetin in recombinant Escherichia coli

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