title: Antioxidant capacity index based on gold nanoparticles formation. Application to extra virgin olive oil samples.
abstract: A simple gold nanoparticles (AuNPs) based colorimetric assay for the antioxidant activity determination has been developed. The AuNP formation is mediated by extra virgin olive oil (EVOO's) endogenous polyphenols; the reaction is described by a sigmoidal curve. The ratio KAuNPs/Xc(50) (slope of the linear part of the sigmoid/concentration at half value of the absorbance) was found to be the optimal parameter to report the antioxidant capacity with respect to the single KAuNPs or Xc(50) values. The obtained data demonstrated that the compounds with ortho-diphenols functionality are most active in reducing gold (III) to gold (0). Thus, intermediate activity was found for gallic acid, while tyrosol (mono-phenols) had a significant lower activity than the others antioxidant compounds (at least one order of magnitude). In the analysis of olive oil samples, a significant correlation among classical methods used to determine antioxidant activity and the proposed parameter was found with R values in the 0.96-0.97 range.
authors.affiliation: Departamento de Química Analítica, Química-Física e Ingeniería Química, Facultad de Química, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain; Facoltà di Bioscienze e Tecnologie Agro-Alimentari e Ambientali, Università degli Studi di Teramo, 64023 Mosciano Sant'Angelo, Italy.
authors.forename: Flavio
authors.initials: F
authors.lastname: Della Pelle
authors.affiliation: Departamento de Química Analítica, Química-Física e Ingeniería Química, Facultad de Química, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
authors.forename: Diana
authors.initials: D
authors.lastname: Vilela
authors.affiliation: Departamento de Química Analítica, Química-Física e Ingeniería Química, Facultad de Química, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
authors.forename: María Cristina
authors.initials: MC
authors.lastname: González
authors.affiliation: Facoltà di Bioscienze e Tecnologie Agro-Alimentari e Ambientali, Università degli Studi di Teramo, 64023 Mosciano Sant'Angelo, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Lo Sterzo
authors.affiliation: Facoltà di Bioscienze e Tecnologie Agro-Alimentari e Ambientali, Università degli Studi di Teramo, 64023 Mosciano Sant'Angelo, Italy.
authors.forename: Darío
authors.initials: D
authors.lastname: Compagnone
authors.affiliation: Facoltà di Bioscienze e Tecnologie Agro-Alimentari e Ambientali, Università degli Studi di Teramo, 64023 Mosciano Sant'Angelo, Italy. Electronic address: mdelcarlo@unite.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Del Carlo
authors.affiliation: Departamento de Química Analítica, Química-Física e Ingeniería Química, Facultad de Química, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain. Electronic address: alberto.escarpa@uah.es.
authors.forename: Alberto
authors.initials: A
authors.lastname: Escarpa
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis*; D010938:Plant Oils / Q000737:chemistry*; D059808:Polyphenols
chemical_list: D000975:Antioxidants; D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils; D059808:Polyphenols; D006046:Gold
keywords: Antioxidant capacity index; Extra virgin olive oil polyphenols; Gold nanoparticles