TEAC antioxidant activity of 4-hydroxybenzoates

Tyrakowska, B.; Soffers, A.E.M.F.; Szymusiak, Henryk; Boeren, Sjef; Boersma, Marelle G.; Lemanska, K.; Vervoort, Jacques; Rietjens, Ivonne M. C. M.

doi:10.1016/s0891-5849(99)00192-6

Cited by 95 publications

(83 citation statements)

References 40 publications

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“…To get IC 50 of extracts turning to transparent color that indicate antioxidant capacity, was calculated by plotting % of inhibition vs. extract concentration; then linear regression equation was calculated (y=mx+b), and 50% inhibitory concentration by the equation IC 50 = (50-b)/m. The results were compared to those obtained using Trolox and Vitamin C (Brand- Williams et al, 1995;Tyrakowska et al, 1999;Kuskoski et al, 2005;Sequeda-Castañeda, 2008).…”

Section: Dpph Methodsmentioning

confidence: 99%

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Evaluation of antioxidant and cytotoxic activity of extracts from fruits in fibroblastoma HT1080 cell lines: four fruits with commercial potential in Colombia

Sequeda-Castañeda

Barrera-Bugallo

Celis

et al. 2016

Emir. J. Food Agric

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Section: Dpph Methodsmentioning

confidence: 99%

“…It was prepared an ABTS solution (1 mg/ml ABTS and 890 µM potassium persulfate) that was incubated at room temperature for 16 hours. The conditions for assessing the antioxidant capacity of the fruit extracts were the same of DPPH assay (Re et al, 1999;Tyrakowska et al, 1999;Kuskoski et al, 2005;Sequeda-Castañeda, 2008). …”

Section: Abts Methodsmentioning

confidence: 99%

Evaluation of antioxidant and cytotoxic activity of extracts from fruits in fibroblastoma HT1080 cell lines: four fruits with commercial potential in Colombia

Sequeda-Castañeda

Barrera-Bugallo

Celis

et al. 2016

Emir. J. Food Agric

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“…scavenging ability of the watersoluble vitamin E analogue, Trolox [17]. The antioxidant activity of catechins and their epimers was measured by the modified TEAC assay performed essentially as described previously [17], with some modifications [18]. The major advantage of the modified TEAC assay is that it permits studying the antioxidant activity over a wide pH range (2-9.5).…”

Section: Teac Assaymentioning

confidence: 99%

“…in phosphate-buffered saline (PBS) pH 7.4. MP8 (final concentration of 0.2 lM) and ABTS (final concentration of 3.0 mM) in PBS were mixed, and the reaction was initiated by the addition of hydrogen peroxide (final concentration of 0.1 mM) [18].…”

Section: Teac Assaymentioning

confidence: 99%

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The influence of stereochemistry on the antioxidant properties of catechin epimers

Muzolf-Panek

Gliszczyńska‐Świgło

Szymusiak

et al. 2012

Eur Food Res Technol

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The influence of stereochemistry on the radical scavenging activity of catechins was investigated by studying the effect of pH on the antioxidant properties of catechin epimers. The difference in the pH-dependent Trolox equivalent antioxidant capacity (TEAC) profiles was observed only in case of gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG), indicating the influence of steric structure on the TEAC antioxidant activity of these galloyl moiety-containing catechins. Based on comparison of the pH-dependent TEAC values to theoretically calculated parameters, including homolytic OH bond dissociation energy and ionization potential (IP) as well as theoretically predicted structures of the most stable monoanions of GCG and EGCG, it was concluded that due to steric hindrance in GCG molecule, the IP value of GCG monoanion increases reflecting lower radical scavenging capacity of GCG in comparison with EGCG. It results in the difference in the pH-dependent TEAC profiles of these two catechin epimers at pH above 3.5. This effect does not occur for other pairs of catechin epimers of this study.

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Radical scavenging mechanism of phenol carboxylic acids: Reaction of protocatechuic esters

2004

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Solvent-dependency of the antiradical reaction of protocatechuic acid (3,4-dihydroxybenzoic acid, PA) and its esters has been investigated. In aprotic solvents, methyl protocatechuate (PAMe) was readily oxidized by two molar equivalents of DPPH radical and converted to protocatechuquinone methyl ester (PQMe). On the other hand, in alcoholic solvents such as methanol, PAMe rapidly consumed five radicals in 30 min and changed to complex oxidized mixtures. A 1H-NMR analysis of the reaction mixture of PAMe and DPPH radical in methanol showed that PAMe was rapidly converted to PQMe and its 3-hemiacetal. In addition, a signal of 2-methoxy-PQMe 3-hemiacetal was also detected in the reaction mixture. The results suggested that PQMe undergoes a nucleophilic attack by the solvent alcohol molecule at the C-2 of the ring in methanol, leading to a regeneration of catechol structure, which accounts well for the higher DPPH radical scavenging activity of PAMe in alcohols than in aprotic solvents.

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TEAC antioxidant activity of 4-hydroxybenzoates

Cited by 95 publications

References 40 publications

Evaluation of antioxidant and cytotoxic activity of extracts from fruits in fibroblastoma HT1080 cell lines: four fruits with commercial potential in Colombia

Evaluation of antioxidant and cytotoxic activity of extracts from fruits in fibroblastoma HT1080 cell lines: four fruits with commercial potential in Colombia

The influence of stereochemistry on the antioxidant properties of catechin epimers

Radical scavenging mechanism of phenol carboxylic acids: Reaction of protocatechuic esters

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