The Antioxidant Activity of Quercetin in Water Solution
AbstractAbstract: Despite its importance, little is known about the absolute performance and the mechanism for quercetin’s antioxidant activity in water solution. We have investigated this aspect by combining differential oxygen-uptake kinetic measurements and B3LYP/6311+g (d,p) calculations. At pH = 2.1 (30 °C), quercetin had modest activity (kinh = 4.0 × 103 M−1 s−1), superimposable to catechol. On raising the pH to 7.4, reactivity was boosted 40-fold, trapping two peroxyl radicals in the chromen-4-one core and two in the catechol with kinh of 1.6 × 105 and 7.0 × 104 M−1 s−1. Reaction occurs from the equilibrating mono-anions in positions 4′ and 7 and involves firstly the OH in position 3, having bond dissociation enthalpies of 75.0 and 78.7 kcal/mol, respectively, for the two anions. Reaction proceeds by a combination of proton-coupled electron-transfer mechanisms: electron–proton transfer (EPT) and sequential proton loss electron transfer (SPLET). Our results help rationalize quercetin’s reactivity with peroxyl radicals and its importance under biomimetic settings, to act as a nutritional antioxidant. View Full-Text
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Amorati, R.; Baschieri, A.; Cowden, A.; Valgimigli, L. The Antioxidant Activity of Quercetin in Water Solution. Biomimetics 2017, 2, 9.
Amorati R, Baschieri A, Cowden A, Valgimigli L. The Antioxidant Activity of Quercetin in Water Solution. Biomimetics. 2017; 2(3):9.Chicago/Turabian Style
Amorati, Riccardo; Baschieri, Andrea; Cowden, Adam; Valgimigli, Luca. 2017. "The Antioxidant Activity of Quercetin in Water Solution." Biomimetics 2, no. 3: 9.
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