Browsing by Author "Dorta Pérez, Eva"
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- ItemControversial alkoxyl and peroxyl radical scavenging activity of the tryptophan metabolite 3-hydroxy-anthranilic acid(2017) Dorta Pérez, Eva; Aspee, E.; Pino, E.; González, L.; Lissi, E.; López Alarcón, Camilo Ignacio
- ItemCytoprotective mechanisms mediated by polyphenols from Chilean native berries against free radical-induced damage on AGS cells(2017) Avila, C. F.; Theoduloz, C.; López Alarcón, Camilo Ignacio; Dorta Pérez, Eva; Schmeda-Hirschmann, G.
- ItemEvaluation of the antioxidant capacity of food samples: a chemical examination of the oxygen radical absorbance capacity assay(WILEY-BLACKWELL, 2018) Dorta Pérez, Eva; Fuentes Lemus, Eduardo Felipe; Speisky, Hernan; Lissi Gervaso, Eduardo A.; López Alarcón, Camilo Ignacio; Apak, Resat; Capanoglu, Esra; Shahidi, FereidoonThis chapter describes, from a critical point of view, the main in vitro methodologies employed to assess the antioxidant capacity (AC) of food samples. Considering the wide use of the oxygen radical absorbance capacity (ORAC) assay, it presents a chemical examination of this methodology. The methods for AC evaluation are based on different strategies; these include the use of colored and stable free radicals, evaluation of the capacity of antioxidants to reduce cupric or ferric ions, estimation of the ability of phenolic compounds (PC) to protect a target molecule exposed to a free radical source, and evaluation of the capacity of PC to form nanoparticles. When the antioxidant activity of a particular sample is evaluated, it is recommended to know the meanings and limitations of the assays being employed. In the case of the ORAC assay, the nature of the free radicals generated during the thermolysis of AAPH should also be considered.
- ItemOxidation of free, peptide and protein tryptophan residues mediated by AAPH-derived free radicals: role of alkoxyl and peroxyl radicals(2016) Fuentes Lemus, Eduardo Felipe; Dorta Pérez, Eva; Escobar Álvarez, Elizabeth; Aspée, A.; Pino, E.; Abasq, M. L.; Speisky, Hernán; Silva, E.; Lissi, E.; Davies, M. J.; López Alarcón, Camilo Ignacio
- ItemOxidation of myofibrillar proteins induced by peroxyl radicals : role of oxidizable amino acids(2019) Dorta Pérez, Eva; Avila, F.; Fuentes Lemus, Eduardo Felipe; Fuentealba Patiño, Denis Alberto; López Alarcón, Camilo Ignacio
- ItemQuantification of carbonate radical formation by the bicarbonate-dependent peroxidase activity of superoxide dismutase 1 using pyrogallol red bleaching(2019) Figueroa Alegría, Juan David; Fuentes Lemus, Eduardo Felipe; Dorta Pérez, Eva; Melin, Victoria; Cortés Ríos, Javiera Alejandra; Faúndez Cáceres, Mario; Contreras, David; Denicola, Ana; Álvarez, Beatriz; Davies, Michael J.; López Alarcón, Camilo IgnacioCarbonate radicals (CO3radical dot-) are generated by the bicarbonate-dependent peroxidase activity of cytosolic superoxide dismutase (Cu,Zn-SOD, SOD-1). The present work explored the use of bleaching of pyrogallol red (PGR) dye to quantify the rate of CO3radical dot- formation from bovine and human SOD-1 (bSOD-1 and hSOD-1, respectively). This approach was compared to previously reported methods using electron paramagnetic resonance spin trapping with DMPO, and the oxidation of ABTS (2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid). The kinetics of PGR consumption elicited by CO3radical dot- was followed by visible spectrophotometry. Solutions containing PGR (5–200 μM), SOD-1 (0.3–3 μM), H2O2 (2 mM) in bicarbonate buffer (200 mM, pH 7.4) showed a rapid loss of the PGR absorption band centered at 540 nm. The initial consumption rate (Ri) gave values independent of the initial PGR concentration allowing an estimate to be made of the rate of CO3radical dot- release of 24.6 ± 4.3 μM min−1 for 3 μM bSOD-1. Both bSOD-1 and hSOD-1 showed a similar peroxidase activity, with enzymatic inactivation occurring over a period of 20 min. The single Trp residue (Trp32) present in hSOD-1 was rapidly consumed (initial consumption rate 1.2 ± 0.1 μM min−1) with this occurring more rapidly than hSOD-1 inactivation, suggesting that these processes are not directly related. Added free Trp was rapidly oxidized in competition with PGR. These data indicate that PGR reacts rapidly and efficiently with CO3radical dot- resulting from the peroxidase activity of SOD-1, and that PGR-bleaching is a simple, fast and cheap method to quantify CO3radical dot- release from bSOD-1 and hSOD-1 peroxidase activity.
- ItemReaction of tetracycline with biologically relevant chloramines(2017) Benavides, J.; Barrias, P.; Piro, N.; Arenas, A.; Orrego, A.; Pino, E.; Villegas, L.; Dorta Pérez, Eva; Aspée, A.; López Alarcón, Camilo Ignacio
- ItemThe ORAC (oxygen radical absorbance capacity) index does not reflect the capacity of antioxidants to trap peroxyl radicals(2015) Dorta Pérez, Eva; Fuentes Lemus, Eduardo Felipe; Aspee, A.; Atala, E.; Speisky, Hernán; Bridi, Raquel; Lissi, E.; López Alarcón, Camilo Ignacio
- ItemUse of Banana (Musa acuminata Colla AAA) Peel Extract as an Antioxidant Source in Orange Juices(2017) Ortiz, Lucía; Dorta Pérez, Eva; Lobo, M. Gloria; González Mendoza, L. Antonio; Díaz, Carlos; González, Mónica
- ItemUse of Banana Peel Extract To Stabilise Antioxidant Capacity and Sensory Properties of Orange Juice During Pasteurisation and Refrigerated Storage(2017) Ortiz, Lucía; Dorta Pérez, Eva; Lobo, M. Gloria; González Mendoza, L. Antonio; Díaz, Carlos; González, Mónica