A kinetic study of the reactions of sulfate and dihydrogen phosphate radicals with epicatechin, epicatechingallate, and epigalocatechingallate

• Autores: Villata, Laura S.; Gonzalez, Monica Cristina; Martire, Daniel Osvaldo
• Año de publicación: 2010
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: SULFATE RADICALS; PHOSPHATE RADICALS; FLAVONOIDS
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The bimolecular rate constants for the reactions of sulfate radicals with epicatechin (EC), epicatechingallate (ECG), and epigallocatechingallate (EGCG) were found to be (1.46 ・}・} 0.06) × 109, (1.20 ・} 0.08) × 109, and (1.04 ・} 0.07) × 109, respectively. The activation energy [EA = 9 ・} 3 kJ mol−1] and preexponential factor [A = (4.8 ・} 0.6) × 1010] for the reaction of EC with the sulfate radical were measured in the temperature range 288–303 K. The phenoxyl radicals of EC (λmax = 310 nm) were obtained both by the reaction of this flavonoid with the sulfate radicals and by photoionization. The measured bimolecular rate constants for the reactions of the dihydrogen phosphate radicals with EC, ECG, and EGCG were (7.8 ・} 0.9) ×× 109, (1.20 ・} 0.08) × 109, and (1.04 ・} 0.07) × 109, respectively. The activation energy [EA = 9 ・} 3 kJ mol−1] and preexponential factor [A = (4.8 ・} 0.6) × 1010] for the reaction of EC with the sulfate radical were measured in the temperature range 288–303 K. The phenoxyl radicals of EC (λmax = 310 nm) were obtained both by the reaction of this flavonoid with the sulfate radicals and by photoionization. The measured bimolecular rate constants for the reactions of the dihydrogen phosphate radicals with EC, ECG, and EGCG were (7.8 ・} 0.9) ×EA = 9 ・} 3 kJ mol−1] and preexponential factor [A = (4.8 ・} 0.6) × 1010] for the reaction of EC with the sulfate radical were measured in the temperature range 288–303 K. The phenoxyl radicals of EC (λmax = 310 nm) were obtained both by the reaction of this flavonoid with the sulfate radicals and by photoionization. The measured bimolecular rate constants for the reactions of the dihydrogen phosphate radicals with EC, ECG, and EGCG were (7.8 ・} 0.9) ×λmax = 310 nm) were obtained both by the reaction of this flavonoid with the sulfate radicals and by photoionization. The measured bimolecular rate constants for the reactions of the dihydrogen phosphate radicals with EC, ECG, and EGCG were (7.8 ・} 0.9) ×・} 0.9) × 108, (8.5 ・} 0.4) × 108, and (6.8 ・} 0.4) × 108, respectively. C 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 391–396, 20108, (8.5 ・} 0.4) × 108, and (6.8 ・} 0.4) × 108, respectively.
Fil: Villata, Laura S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
Fil: Gonzalez, Monica Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
Fil: Martire, Daniel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina