Higher Total Antioxidant Capacity Values Research Articles

Purple grape juice improves performance of recreational runners, but the effect is genotype dependent: a double blind, randomized, controlled trial

BackgroundWe examined the influence of superoxide dismutase 3 (SOD3) Arg213Gly and Peroxisome Proliferator-Activated α-Receptor (PPARα) 7G/C polymorphisms to a single dose of purple grape juice supplementation on time-to-exhaustion running test, redox balance and muscle damage in recreational runners.MethodsForty-seven male recreational runners performed a running test until exhaustion after supplementation with grape juice or a control drink. Serum total antioxidant capacity (TAC), malondialdehyde (MDA), plasma nitrite (NO), creatine kinase (CK) and lactate dehydrogenase (LDH) were measured pre and post exercise. Also, polymorphisms were analyzed in DNA extracted from the oral mucosa.ResultsGrape juice improved the time-to-exhaustion. When analyzed by genotype, the recreational runners with GG+CG genotypes of the SOD3 gene had greater time-to-exhaustion than the CC genotype, but was no different for the PAPRα gene. A slight difference was noted in TAC, since the CC genotype of the SOD3 gene showed higher TAC values in the post-exercise compared to the baseline and with pre-exercise, but these values did not increase compared to the CG+GG group, respectively. The SOD3 and PPARα genes were similar at all times for the other biochemical variables.ConclusionThe ergogenic effect of grape juice was genotype-dependent for SOD3 Arg213Gly. However, biochemical redox balance markers did not explain this difference.

Differential Response of Phenol Metabolism Associated with Antioxidative Network in Elicited Grapevine Suspension Cultured Cells under Saline Conditions.

Highly productive trans-resveratrol (t-R) grapevine suspension cultured cells (SCC) and two effective elicitors, methyl jasmonate (MJ) and randomly methylated β-cyclodextrins (CDs), were used to analyze the extent to which salt treatments alter the production of bioactive phenolic compounds. The expression/activity profile of the enzymes involved in phenol metabolism and antioxidant networks were also studied. A marked extracellular accumulation of phenolic compounds, especially t-R, was found in SCC elicited with CDs and/or MJ under saline conditions. However, the treatments with MJ alone and all those combined with salt favored the intracellular accumulation of catechin and ferulic acid. The salt-induced accumulation of phenolics was correlated with the higher total antioxidant capacity values found in cells, suggesting that cellular redox homeostasis under saline conditions was largely maintained by increasing phenolic compound production. These higher levels of phenolics found in elicited cells under saline conditions fit well with the highest activity of phenylalanine ammonia-lyase. Moreover, antioxidant enzyme activities were boosted in treatments with MJ and/or in those combined with salt and decreased in those treated with CDs. These results suggest a differential response of the antioxidative network to the presence of elicitors under saline conditions.

Polyphenols and antioxidant activity in pseudocereals and their products

Pseudocereals are important as gluten-free crops that could be utilized as functional foods. They contain proteins with high biological value and also bioactive compounds such as phenolic compounds, flavonoids, vitamins, and minerals that can possess positive health effects on the body. Three types of pseudocereals (amaranth, buckwheat, and quinoa) were evaluated for polyphenols and antioxidant activity. Spectrophotometric methods were used for the determination of free phenols amount with Folin-Ciocalteu reagent, and total antioxidant capacity (TAC) with DPPH and ABTS reagents. Free phenols, the predominant part of polyphenols, were in pseudocereals in the range from 12.4 to 678.1 mg GAE.100g-1. The highest content of FP was found in buckwheat products (146.8 - 678.1 mg GAE.100g-1); quinoa and amaranth products reached much lower values (up to 226.1 mg GAE.100g-1). Antioxidant activity was in an agreement with the FP amounts order, the highest TAC values were again for buckwheat products (167.3 - 473.9 and 876.9 - 3524.8 mg TE.100g-1), followed by quinoa (78.2 - 100.6 and 738.9 - 984.5 mg TE.100g-1) and amaranth ones (25.0 - 69.7 and 118.2 - 431.4 mg TE.100g-1). A high positive correlation between FP amount and TAC values was evaluated for analyzed pseudocereals. The highest content of free phenols and the best antioxidant potential showed buckwheat wholemeal flour, so buckwheat could be characterized as a great source of free phenols with high antioxidant activity.

Effect of the solid–liquid extraction solvent on the phenolic content and antioxidant activity of three species of Stevia leaves

ABSTRACTIn our study, it was found that solid–liquid extraction solvent influenced the phenolic content in leaf extracts of Stevia origanoides, S. ovata and S. viscida. The highest total phenolic and flavonoids contents, the highest scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical, and the highest total antioxidant capacity values were observed when 50% ethanol was used. The phenolic compounds identified in the Stevia leaf extracts by high-performance liquid chromatography with diode array detection (HPLC-DAD) include phenolic acids such as chlorogenic, caffeic, p-coumaric and vanillic acid, as well as flavonoids such as quercetin and kaempferol.

Moderate UV-C pretreatment as a quality enhancement tool in fresh-cut Bimi ® broccoli

The effects of several UV-C pre-treatments (1.5, 4.5, 9.0 and 15 kJ m −2) on changes in physiological, sensory and microbial quality and health promoting bioactive compounds over 19 days at 5 and 10 °C of fresh-cut Bimi ® broccoli were studied. Non-irradiated samples were used as controls. Bimi ® broccoli ( Brassica oleracea Italica Group × Alboglabra Group) is characterised by a long stem with a small floret with a mild and sweeter flavor than conventional varieties well adapted for fresh-cut purposes. Low and moderate UV-C doses (1.5 and 4.5 kJ m −2) had inhibitory effects on natural microflora growth. In relation to sensory quality, all treatments resulted in a shelf-life of 19 and 13 days at 5 and 10 °C respectively with the exception of 15 kJ UV-C m −2 treated samples which resulted in a shorter shelf-life. These doses immediately increased total polyphenols contents up to 25% after 19 days at 5 °C compared to the initial value. All the hydroxycinnamoyl acid derivates were immediately increased after UV-C treatments, with values 4.8- and 4.5-fold higher for 4.5 and 9.0 kJ UV-C m −2 treated samples respectively over the control. Changes in phenolic compounds were highly influenced by the storage temperature throughout shelf-life. Total antioxidant activity generally followed the same pattern: the higher the UV-C doses, the higher total antioxidant capacity values. Generally, UV-C slightly reduced initial total chlorophyll content but delayed its degradation throughout shelf-life. It is concluded that a pre-treatment of 4.5 kJ UV-C m −2 is useful as a technique to improve epiphytic microbial quality and health promoting bioactive compounds of fresh-cut Bimi ® broccoli.

Tocotrienamines and tocopheramines: Reactions with radicals and metal ions

The antioxidant activity of vitamin E (VE) homologs α, γ and δ-tocotrienamines (4b–6b), never studied before, and α, γ and δ-tocopheramines (4a–7a) was investigated by means of different total antioxidant capacity (TAC) tests. In all the test model systems, compounds 4a–7a and 4b–6b showed similar or higher TAC values than the parental vitamin E forms and their physiological metabolites. α-Homologs of VE amines showed markedly higher activity than the VE congeners in the TEAC test, which is tailored for liposoluble antioxidants, while γ-homologs of the amine analogs showed higher activity in the FRAP tests. Kinetics analysis of the reaction with DPPH showed higher second order rate k for 4a than for α-tocopherol (1a). α-Tocopherolquinone 1f was the common main oxidation product for both 1a and α-tocopheramine (4a) exposed to ferric ions or DPPH, and the implied oxidative deamination of 4a was accompanied by a nitration reaction of phenolic substrates that were added to the reaction medium. Possible mechanisms of these reactions were studied.

Selenoprotein H Is a Redox-sensing High Mobility Group Family DNA-binding Protein That Up-regulates Genes Involved in Glutathione Synthesis and Phase II Detoxification

Selenoprotein H is a recently identified member of the selenoprotein family whose function is not fully known. Previous studies from our laboratory and others showed that Drosophila melanogaster selenoprotein H is essential for viability and antioxidant defense. In this study we investigated the function of human selenoprotein H in murine hippocampal HT22 cells engineered to stably overexpress the protein. After treatment of cells with L-buthionine-(S,R)-sulfoximine to deplete glutathione, selenoprotein H-overexpressing cells exhibited higher levels of total glutathione, total antioxidant capacities, and glutathione peroxidase enzymatic activity than did vector control cells. Overexpression of selenoprotein H also up-regulated the mRNA levels of endogenous selenoprotein H, glutamylcysteine synthetase heavy and light chains, and glutathione S-transferases Alpha 2, Alpha 4, and Omega 1. The amino acid sequence of selenoprotein H contains four putative nuclear localization sequences and an AT-hook motif, a small DNA-binding domain first identified in high mobility group proteins. Chromatin immunoprecipitation using a green fluorescent protein-selenoprotein H fusion revealed binding to sequences containing heat shock and/or stress response elements. Thus, selenoprotein H is a redox-responsive DNA-binding protein of the AT-hook family and functions in regulating expression levels of genes involved in de novo glutathione synthesis and phase II detoxification in response to redox status.