title: Antioxidant and radical-scavenging activities of Slovak honeys - An electron paramagnetic resonance study.
abstract: The antioxidant properties of 15 honey samples from different floral sources and various Slovak regions were investigated by means of electron paramagnetic resonance spectroscopy. Cation radical of ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt), DPPH (1,1-diphenyl-2-picrylhydrazyl) and hydroxyl radicals generated by the photochemical decomposition of hydrogen peroxide were used as oxidants. The antioxidant activities found with ABTS(+), expressed as trolox equivalent antioxidant capacity (TEAC), ranged from 0.15 to 1.14mmolkg(-1), and those determined with DPPH, from 0.04 to 0.32mmolkg(-1). TEAC values correlated well with results found by elimination of DPPH, and both values revealed a linear relationship with the concentration of phenolics obtained with the Folin-Ciocalteu phenol test (expressed as gallic acid equivalents, GAE). The colour coordinates (CIE L(∗)a(∗)b(∗)), as well as reflectance spectra determined for original honeys using a white background, demonstrated that the colour difference (ΔE(∗)) and coordinate b(∗) interrelate with TEAC values. The radical-scavenging capacities (RSC) of the honey samples determined in the experiments with photochemically decomposed hydrogen peroxide, generating reactive OH radicals in the presence of spin trapping agent, differ from those found with ABTS(+) and DPPH. Here, probably, the reactive OH radicals, having higher redox potential, are scavenged by a variety of compounds not effective with ABTS(+) and DPPH (e.g., saccharides, proteins).
authors.affiliation: Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava,Radlinského 9, SK-812 37 Bratislava, Slovak Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Zalibera
authors.affiliation: Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava,Radlinského 9, SK-812 37 Bratislava, Slovak Republic.
authors.forename: Andrej
authors.initials: A
authors.lastname: Staško
authors.affiliation: Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava,Radlinského 9, SK-812 37 Bratislava, Slovak Republic.
authors.forename: Anna
authors.initials: A
authors.lastname: Šlebodová
authors.affiliation: Institute of Polymer Materials, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9,SK-812 37 Bratislava, Slovak Republic.
authors.forename: Viera
authors.initials: V
authors.lastname: Jančovičová
authors.affiliation: Research Institute of Animal Production, Institute of Apiculture, Gasperiková 599, SK-033 80 Liptovský Hrádok, Slovak Republic.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Čermáková
authors.affiliation: Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava,Radlinského 9, SK-812 37 Bratislava, Slovak Republic. Electronic address: vlasta.brezova@stuba.sk.
authors.forename: Vlasta
authors.initials: V
authors.lastname: Brezová
keywords: Antioxidant; Colour coordinates; DMPO; DPPH; EPR; Honey; Phenolics; TEAC