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The experimental conditions commonly used to detect bound phenolic acids by alkaline hydrolysis result in loss of several phenolic acids, particularly dihydroxy-derivatives (caffeic acid, dihydrocaffeic acid, homogentisic acid). In this study we show that the addition of ascorbic acid, a strong antioxidant, and ethylenediaminetetraacetic acid, a metal chelator, totally prevent the loss of phenolic acids during alkaline hydrolysis. In these conditions, a complete recovery of caffeic acid following hydrolysis of chlorogenic acid (5′-caffeoylquinic acid, an ester of caffeic acid with quinic acid) was found. This procedure has been successfully applied to quantitatively detect bound phenolic acids in coffee brew and apple. [Copyright &y& Elsevier]

Abstract: Aim of this study was to analyse the relationship between the plasma levels of polyphenols and the antioxidant activity of red and white wine. Twenty healthy subjects (HS) were randomly allocated to drink 300ml of red (n =10) or white n =10 wine for 15 days. Ten HS who refrained from any alcohol beverage for 15 days were used as control. Urinary PGF-2α-III, a marker of oxidative stress and plasma levels of polyphenols were measured. Urinary PGF-2α-III significantly fell in subjects taking wine with a higher percentage decrease in subjects given red wine (−38.5±6%, p <0.001) than in those given white wine (−23.1±6%). Subjects taking red wine had higher plasma polyphenols than those taking white wine (1.9±0.6μM versus 1.5±0.33μM, p <0.001). Plasma polyphenols were inversely correlated with urinary PGF2α (r =0.77, p <0.001). No changes of urinary isoprostanes were observed in subjects who refrained from wine intake. In vitro study demonstrated that only a mixture of polyphenols, all in a range corresponding to that found in human circulation, inhibited LDL oxidation and PKC-mediated NADPH oxidase activation. Such inhibitory effects were more marked using the concentrations of polyphenols detected in human circulation after red wine intake. This study shows that red wine is more antioxidant than white wine in virtue of its higher content of polyphenols, an effect that may be dependent upon a synergism among polyphenols. [Copyright &y& Elsevier]

UM-X7.1 hamsters (CH) are considered a representative model for human cardiomyopathy. CH display the loss of the cytoskeletal δ-sarcoglycan protein, associated with myocardium remodeling and fatal reduction of heart functional efficiency. Even though altered redox balance and calcium homeostasis have already been reported to affect cardiomyocyte function, the molecular mechanisms underlying this pathology are largely unknown. We found no significant differences in DNA binding activity of redox-related (NF-κB, Sp1, AP-1 and AP-2) transcription factors in heart ventricles of 90 day-old CH, compared to normal animals. On the other hand, DNA binding activity of calcium-dependent transcription factors NF-AT3 and CREB were increased and decreased respectively in CH vs. normal ventricles. Western blot experiments confirmed the down regulation of CREB levels and suggest a novel regulation mechanism for this transcription factor in the heart.Our results are consistent with recent studies on NF-AT3, GATA4 and CREB transgenic mice, and provide clues for the comprehension of pathogenetic mechanisms of hamster hereditary cardiomyopathy. [Copyright &y& Elsevier]