Flow injection analysis of DPPH radical based on electron spin resonance

Genesis and development of DPPH method of antioxidant assay

“…Inclusion of automation Several automation in the original DPPH assay, based on flow injection analysis (FIA) (Ukeda et al 2002;Ukeda 2004), sequential injection analysis (SIA) (Polasek et al 2004) and HPLC-FIA (Yamaguchi et al 1998) have been implemented in recent years. These methods were applied for screening and evaluation of scavenging capacity of several pure compounds and complex matrices, such as plant extracts and beverages.…”

A comparative study on the antioxidant properties of Slovakian and Austrian wines

“…There are various methods to determine the antioxidant capacity, but unfortunately their significance is questionable due to the varied experimental and methodological approaches (Antolovich, Prenzler, Patsalides, McDonald, & Robards, 2002;Arnao, 2000;Aruoma, 2003;Becker, Nissen, & Skibsted, 2004;Fogliano, et al, 1999;Kilmartin, Zou, & Waterhouse, 2001;Kiralp & Toppare, 2006;Perez, Leighton, Aspee, Aliaga, & Lissi, 2000;Re et al, 1999;Roginsky & Lissi, 2005;Sanchez-Moreno, 2002;Schwarz et al, 2001). The antioxidant activity is frequently determined using as oxidants DPPH, ABTS þ , TEMPOL, ORAC (Oxygen Radical Absorbance Capacity) and other assays (Bartosz, Janaszewska, Ertel, & Bartosz, 1998;Milardović, Iveković, & Grabarić, 2006;Mira, Silva, Rocha, & Manso, 1999;Rupasinghe & Clegg, 2007;Ukeda, Adachi, & Sawamura, 2002;Villaño, Fernandéz-Pachón, Moyá, Troncoso, & García-Parrilla, 2007;. However, the variety of experimental conditions (oxidants used, reaction time, and evaluation procedures) hinders exact comparison of the samples investigated in various laboratories.…”

Characterization of Superoxide Anion Scavenging Compounds in Roselle (Hibiscus sabdariffa L.) Extract by Electron Spin Resonance and LC/MS

“…Into a mixture containing 50 μl of 4 mM HPX, 30 μl of DMSO, 50 μl of sample solution (Roselle extract, Roselle crude pigments or authentic anthocyanins), and 20 μl of 4.5 mol/l DMPO, 50 μl of 0.1 U/ml XOD were added to start the generation of superoxide anion. The reaction mixture was transferred into the flat quartz cell designed for aqueous solution (Ukeda et al, 2002), and scanning of ESR spectra were started at below 21℃ exactly 60 s after the addition of XOD. The superoxide anion scavenging capacity of antioxidative compounds was expressed as scavenging rate (%): [(intensity relative to Mn (II) in the control) -(intensity relative to Mn (II) in the sample)]/(intensity relative to Mn (II) in the control)×100.…”

“…Some of these methods are timeconsuming and prone to interference by the pigments in samples when measured photometrically. Being more sensitive and selective, electron spin resonance (ESR) methods were proposed along with free radical generation systems and spin trapping techniques (Chen et al, 2000;Deguchi et al, 2000;Ukeda et al, 2002;Yamaguchi et al, 2000;Yoshimura et al, 1999).…”