Inhibition of induced DNA oxidative damage by beers: Correlation with the content of polyphenols and melanoidins
ABSTRACT Beers are a source of dietary flavonoids; however, there exist differences in composition, alcohol concentration, and beneficial activities. To characterize these differences, three kinds of lager beer of habitual consumption in Spain, dark, blond, and alcohol-free, were assayed for total phenolic content, antioxidant activity, superoxide and hydroxyl radical scavenging activities, and in vitro inhibitory effect on DNA oxidative damage. Furthermore, their melanoidin content and correlation with antioxidant activity were evaluated. Dark beer contained the highest total phenolic (489 +/- 52 mg/L) and melanoidin (1.49 +/- 0.02 g/L) contents with a 2-fold difference observed when compared to the alcohol-free beer. For the three kinds of beer, the antioxidant activity measured as N,N-dimethyl-p-phenylenediamine dihydrochloride concentration was strongly correlated with the total polyphenol content (R(2) = 0.91102, p < 0.005) and with the melanoidin content (R(2) = 0.7999, p < 0.05). The results support a positive effect of beers on the protection of DNA oxidative damage, by decreasing the deoxyribose degradation, DNA scission (measured by electrophoresis), and inhibition of 8-hydroxydeoxyguanosine (8-OH-dG) formation. Furthermore, a correlation between the total melanoidin content (R(2) = 0.7309, p < 0.01) and inhibition of 8-OH-dG was observed.
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ABSTRACT: Melanoidins are the final products of the Maillard reaction. The main dietary sources of melanoidins are coffee, bread crust, bakery products, black beer and cocoa. Although the chemical structures of melanoidins are widely unknown, data from gravimetric techniques allow to roughly estimate a daily intake in the order of 10 g with a Western diet. Melanoidins contribute to the sensorial properties, modulating texture and flavour of foods. Growing evidence also suggests that melanoidins have health beneficial properties, such as chemopreventive, antioxidant and antimicrobial activities, and the ability to chelate different minerals. In the gastrointestinal tract, melanoidins behave not only as antioxidants, but also as dietary fibre by promoting the growth of bifidobacteria. This array of biological activities suggests the need for analytical techniques to identify the melanoidin structures and to control their formation during thermal food processing.Amino Acids 10/2010; 42(4):1097-109. DOI:10.1007/s00726-010-0774-1 · 3.65 Impact Factor
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ABSTRACT: The bacteriophage P22/Salmonella Typhimurium system, as well as human erythrocytes have been used to assay for protection, against forced oxidation caused by hydrogen peroxide, brought about by several aqueous extracts of selected adventitious plants grown in Portugal.This study proved, for the first time, that the aforementioned bacteriophage-based system is a suitable method to assess the antioxidant activity of plant extracts; among the 12 plants tested, raspberry (Rubus idaeus), sage (Salvia sp.), savory (Satureja montana) and yarrow (Achillea millefolium) were found to effectively protect against oxidative damage caused by H2O2. Haemolysis was inhibited via pre-treatment with every plant extract tested, except heath at 0.1%(w/v).The two analytical methods produced different results – and for some plants, there was a dependence (either direct or inverse) of the quantitative protection effect on extract concentration, whereas for others no significant dependence was found at all. Savory yielded the most promising results, using either method.Therefore, the P22/Salmonella system can be used as a suitable in vivo assay, and human erythrocytes as a suitable in vitro assay to confirm (or not) the antioxidant capacity of plant extracts in biological matrices.Food Control 05/2010; 21(5):633-638. DOI:10.1016/j.foodcont.2009.08.014 · 2.82 Impact Factor
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ABSTRACT: We assessed the influence of alcohol-free beer on factors implicated in atherosclerosis, such as lipid profile, oxidative stress parameters, and proinflammatory cytokines, in postmenopausal women, a population particularly at risk for atherosclerotic disease. The study was carried out in 29 nuns, 58 to 73 y old, who live in a convent with a disciplined, regular, and homogeneous lifestyle. The nuns maintained their habits and diet routine, but their meals were supplemented with 500 mL/d of alcohol-free beer (0.0%) divided into two doses over a 45-d period. Lipid profile, inflammatory markers such as C-reactive protein, interleukins 1 and 6, and tumor necrosis factor-alpha, and parameters of oxidative metabolism were determined before and after the study period. There were no differences in the levels of C-reactive protein and proinflammatory cytokines after diet supplementation. The antibody titers to oxidized low-density lipoprotein were significant lower (P < 0.05), and thiobarbituric acid-reactive substances (-18%, P < 0.001) and plasma carbonyl group content (-21%, P < 0.001) were decreased when compared with initial values. Increases in alpha-tocopherol levels (+9%, P < 0.05) and erythrocytic glutathione levels (+29%, P < 0.001) were also noted. With respect to lipid profile, only subjects with cholesterol levels higher than 240 mg/dL showed lower levels after supplementation. Consumption of non-alcoholic beer produces a decrease in oxidative stress that can have a beneficial impact on cardiovascular risk; however, the circulating concentrations of inflammatory mediators involved in its pathophysiology remained unchanged.Nutrition 10/2008; 25(2):182-7. DOI:10.1016/j.nut.2008.08.005 · 3.05 Impact Factor