Phenolic antioxidants and the protection of low density lipoprotein from peroxynitrite-mediated oxidations at physiologic CO2

Dietary phenolic antioxidants have been shown to prevent LDL modifications mediated by several physiologic oxidants including peroxynitrite. However, more recent data demonstrated that CO(2) affected the fate of peroxynitrite in biological fluids and significantly reduced peroxynitrite scavenging by polyphenols, raising doubts concerning their antioxidant activity. We found that the oxidation of LDL lipids mediated by peroxynitrite decreased in the presence of bicarbonate, while Trp oxidation and 3-nitroTyr formation increased, suggesting a redirection of peroxynitrite reactivity toward the protein moiety. We therefore evaluated the protective activity of some phenolic antioxidants (quercetin, oleuropein, resveratrol, (+)-catechin, (-)-epicatechin, tyrosol, alpha- and gamma-tocopherol, ascorbate) on peroxynitrite-mediated oxidation of LDL aromatic residues. Some of these phenols protected LDL Trp from oxidation better than ascorbate or alpha-tocopherol, although protection at 100 microM did not exceed 30-40%. However, the same phenolic antioxidants were more active in inhibiting 3-nitroTyr formation and those with a catechin structure provided significant protection (IC(50%) 40-50 microM). Red wine, a polyphenol-rich beverage, showed a protective effect comparable to that of the most active phenolic antioxidants. Direct EPR studies showed that bicarbonate significantly increased the peroxynitrite-dependent formation of O-semiquinone radicals in red wine, supporting the hypothesis that polyphenols are efficient scavengers of radicals formed by peroxynitrite/CO(2). Ascorbate was a poor inhibitor of peroxynitrite/CO(2)-induced LDL tyrosine nitration, but the simultaneous addition to the most active polyphenols halved their IC(50%). In conclusion, although cooperation with other antioxidants can further decrease the IC(50%) of polyphenolics, as demonstrated for ascorbate, their antioxidant activity appears to occur at concentrations at least 1 order of magnitude higher than their bioavailability.     

Hydrolysis of wine aroma precursors during malolactic fermentation with four commercial starter cultures of Oenococcus oeni

The ability of four commercial preparations of Oenococcus oeni lactic acid bacteria (EQ 54, Lalvin OSU, Uvaferm Alpha, and Lalvin 31) to hydrolyze wine aroma precursors was evaluated by measuring the concentration of free and bound aroma compounds at the end of malolactic fermentation carried out in model wines containing a mixture of glycosides extracted from Muscat wine. At pH 3.4 there was a decrease in glycosylated compounds matched by a concomitant increase in free forms in all starter cultures tested. When malolactic fermentation was carried out at pH 3.2, a significant decrease in the ability to hydrolyze aroma precursors was observed for two of the cultures tested (Uvaferm Alpha and Lalvin 31). Large differences in the extent of hydrolysis and in the specificity of this activity toward specific aroma precursors were observed and appeared to be related to the chemical structure of the aglycon as well as to individual characteristics of each starter culture. The amounts of glycosylated aroma compounds released during malolactic fermentation suggest that O. oeni can alter the sensory characteristics of wine through the hydrolysis of aroma precursors.     

The effect of recumbency and hindlimb position on the lumbosacral interlaminar distance in dogs: a cadaveric computed tomography study

Objective

To examine the effect of sternal or lateral recumbency, with or without cranial extension of the hindlimbs, on the distance between the dorsal lumbosacral laminae in dogs.

Circulating Salicylic Acid and Metabolic and Inflammatory Responses after Fruit Ingestion

We hypothesized that fruit ingestion provides measurable amounts of salicylic acid (SA) and produces different metabolic and inflammatory responses compared to mere fruit sugars. In a randomized-crossover study, 26 healthy subjects received a peach shake meal (PSM) (SA: 0,06 ± 0,001 mg/100 g) and a mixed sugar meal (MSM), consisting in an aqueous solution with the same sugars found in the peach shake. In order to control for the SA contribution from meals in the previous day, 16 subjects (Group 1) abstained from fruits and vegetables consumption the evening before trials, and 10 subjects (Group 2) maintained their usual diet. Circulating SA, glucose, insulin, free fatty acids, and interleukin-6 were determined. Basal SA was lower in Group 1 than in Group 2 (0.09 ± 0.02 vs. 0.30 ± 0.03 μmol/l, p < 0.001), peaked at 90 min in both groups (0.18 ± 0.01 vs. 0.38 ± 0.02 μmol/l, p < 0.01) and remained above baseline (p < 0.05) up to 3 h. Glycemia increased less after PSM at 15 min (p < 0.01) with a lower average glucose excursion (p < 0.05). Insulin peaked at 45 min with both meals but decreased less rapidly with PSM. Free fatty acids decreased more (p < 0.01), and interleukin-6 increased less (p < 0.05) with PSM. Dietary fruit intake increases the concentration of SA in vivo, and provides non-nutrients capable to modulate the inflammatory and metabolic responses to carbohydrates.     

Consumer perceptions of food safety risk：Evidence from a segmentation study in Albania

Albania is facing serious problems with the national food safety control system in terms of legislation, control and enforce-ment. The objective of this paper is to analyse consumer perceptions about s...     

Synthesis and in-vitro antifungal activity of 6-trifluoromethylpyrazolo[3,4-d]pyrimidines

Thirty 6-trifluoromethylpyrazolo[3,4-d]pyrimidines were synthesised and tested for antifungal activity in vitro against ten phytopathogenic fungi of different taxonomic classes. Six of the compounds had noteworthy activity against Sclerotinia minor, Corticium solani and Phoma betae. The relationships between structure and activity are discussed on the basis of the present and previous studies.     

Strigolactones--intriguing biologically active compounds: perspectives for deciphering their biological role and for proposing practical application

Strigolactones are a class of bioactive natural metabolites produced by plant roots and released into the rhizosphere. They were discovered as signals indispensable for the induction of germination of seeds of root parasitic weeds, but since then, interestingly, many other biological, physiological and ecological roles have been described. This has suddenly provoked huge scientific interest in these compounds within different research fields. In this short perspective the attention is focused mainly on the ongoing and future research aimed at deciphering the biological roles of strigolactones that could positively affect, more or less directly, the management of parasitic weeds.     

Confirmation of perfluidone residues in rice by gas-liquid chromatography following the formation of derivatives

A simple and sensitive method for the confirmation of perfluidone residues in rice grains is described. The procedure involves extraction, purification on an anionexchange resin, chlorination, methylation and gas-chromatographic analysis with electron capture detection. The recoveries from fortified rice grains varied from 84.0 to 92.4% in the range 0.01–0.20 mg/kg. The sensitivity was such that perfluidone could be detected down to a level of 0.005 mg/kg. The method can be used for confirmation of perfluidone quantitatively as well as qualitatively.