LAUSR

INTRODUCTION An imbalance between oxidants and antioxidants in favour of oxidants, potentially leading to damage, is termed oxidative stress. Antioxidants (AO), either enzymatic or non-enzymatic, are the ones that can reduce diverse effects of pro-oxidants such as DNA, proteins and lipids damage. Chalcones (1,3-diaryl-2-propen-1-ones) are open chain flavonoids that are widely biosynthesized in plants. Aim of this study was to test antioxidative potency of 15 chalcones (Chs) in in vitro model in serum (native conditions), so as with exogenously induced oxidative stress. MATERIAL AND METHODS Oxidative stress was induced in serum samples of healthy individuals with 0.25 mmol/L terc-buthyl-hydroperoxide (TBH), and then we monitored the effects of various concentrations of chalcones on oxidative stress parameters: total antioxidative status (TAS), total oxidative status (TOS), total concentration of sulfhydryl group (SHG) and prooxidative-antioxidative balance (PAB), and calculated prooxidative score, antioxidative score, and oxy score (OS). Nonparametric repeated measures ANOVA (Friedman's test) was used for comparison of antioxidative potency of samples with 15 different chalcones, in a native state and upon TBH influence. Spearman's nonparametric correlation analysis was used for estimation of relation between different parameters. RESULTS Negative Oxy Score (OS) values for Chs11-15 showed significantly stronger antioxidative potency compared to other investigated chalcones (p < 0.05). Ch11, Ch13 and Ch14 remained with negative OS even after TBH addition, whereas OS of Ch12 and Ch15 became positive, with small nominal values. Samples with Ch11 and Ch13 showed significant negative correlation between TAS and TOS (p < 0.05 for both), but in Ch14 sample the negative correlation existed between TAS and PAB (p < 0.05). CONCLUSION Lower value of OS (i.e. better antioxidative potency) was noticed in samples with Ch11-Ch15. Electron-donor effects of substituent groups as a structural part of these chalcones could explain its antioxidative capability. Phenolic and methyl groups are responsible for antioxidative ability enhancement of five chalcones with the best activity.