Reduced-Oxidized Glutathione Status as a Potential Index of Oxidative Stress in Mature Cereal Grain

The purpose of this study was to examine the reduced and oxidized glutathione status of selected cereal grains as a potential index of balance between oxidative stress and antioxidant systems, and the contribution of reduced glutathione to the total antioxidant status in cereal grain extracts. Wheat cultivars Almari and Henika, barley cultivars Gregor and Mobek, rye cultivar Dañkowskie Złote, oat cultivar Sławko, and buckwheat cultivar Kora were used. Total antioxidant status (TAS) was measured by the ABTS (2,2'-azinobis(3-ethyl-benzothiazoline-6-sulphonate)) method. Contents of total phenolic compounds were also determined. Reduced (GSH) and oxidized glutathione (GSSG) (γ-glutamyl-cysteinyl-glycine) were assayed using the spectrofluorimetric method, and results were confirmed by the enzyme recycling method. Correlation coefficient for the GSH/GSSG ratio was r = 0.79. Correlation between TAS and the total phenolic compound content was r = 0.81. Correlation between GSH/GSSG ratio and TAS values was r= 0.46, depending on the extraction system used. The GSH/GSSG ratio may indicate a hierarchy among different cultivars and variance of cereal grains against damage caused by reactive oxygen species. For the main water-soluble antioxidants, our data indicate a potential hierarchy of resistance in investigated cereals against oxidative stress (buckwheat > wheat > barley ≈ rye > oat). This hierarchy was confirmed by the ability of investigated cereal extracts to scavenge superoxide anion radicals in vitro. The reduced-oxidized glutathione status in different cereal grains can be applied as a potential index of balance between oxidative stress and antioxidant systems.     

The stomach as a "bioreactor": when red meat meets red wine

To determine the stomach bioreactor capability for food oxidation or antioxidation, rats were fed red turkey meat cutlets (meal A) or red turkey meat cutlets and red wine concentrate (meal B). The hydroperoxides (LOOH) and malondialdehyde (MDA) levels of the stomach contents were evaluated during and after digestion; the postprandial plasma MDA level was also evaluated. In independently fed rats, the stomach LOOH concentration fell substantially 90 min following the meal, and the addition of red wine polyphenols enhanced LOOH reduction 3-fold. A similar trend was obtained for MDA. After pyloric ligation, the stomach contents of rats fed red meat homogenate showed >2-fold increases in LOOH and MDA accumulation. The postprandial plasma MDA level increased significantly by 50% following meal A and was maintained or even fell by 34% below basal level following meal B. The findings show that consumption of partially oxidized food could increase lipid peroxidation in the stomach and the absorption of cytotoxic lipid peroxidation products into the body. The addition of antioxidants such as red wine polyphenols to the meal may alter these outcomes. These findings explain the potentially harmful effects of oxidized fats in foods and the important benefit of consuming dietary polyphenols during the meal.     

Influence of dietary quercetin on glutathione redox status in mice

Flavonoids such as quercetin have been shown to serve as a protective defense against oxidative damage in vivo. However, the bioavailability of quercetin depends on the food source and type of glycosidic moiety linked to the molecule. In this study, mice were fed 1 mg/day quercetin in the form of quercetin aglycone, rutin, apple, or onion, and reduced glutathione (GSH), oxidized glutathione (GSSG), and protein-GSH mixed disulfides were determined to investigate the influence of dietary quercetin on the GSH redox status in metabolically active tissues, mitochondria, and plasma of mice. All quercetin treatment groups produced increases in the GSH:GSSG ratio and decreases in mixed disulfide levels in hepatic tissue. Cardiac tissue did not change in response to dietary quercetin; however, cardiac mitochondria demonstrated a reduction in the GSH:GSSG ratio and an increase in protein mixed disulfide levels. No significant changes were observed in the plasma GSH:GSSG ratio, but mixed disulfide levels were decreased for all of the diets. The changes in plasma redox status did not parallel the changes in the tissues. Onion fed mice demonstrated the greatest increases in GSH:GSSG ratios and the greatest decreases in protein mixed disulfide levels of all diets compared. For all treatment groups, increases in the GSH:GSSG ratios corresponded with decreases in protein mixed disulfide levels. The results of this study indicate that quercetin influences GSH:GSSG ratios and protein thiolation in a tissue-specific manner and that these effects are dependent on food source and bioavailability.     

Impact of food disinfection on beneficial biothiol contents in strawberry

In this study, the impact of four food disinfectants including hydrogen peroxide, free chlorine, and gaseous- and aqueous-phase ozone with industrial doses on the concentration of biothiol compounds gamma-glutamylcysteinylglycine (GSH) and cystein (CYS) in strawberry was investigated for 1, 5, 15, 30, and 60 or 120 min. Additionally, the amount of oxidized glutathione (GSSG) was analyzed for calculation of the GSH/GSSG ratio as an indicator of oxidative stress. After this treatment, thiol contents of strawberry samples were examined using high-performance liquid chromatography (HPLC) technique. According to the results of measurements, free chlorine treatment for only 60 min significantly decreased CYS content in strawberry (p < 0.05). A significant decline in the GSH/GSSG ratio was also observed when H2O2 was applied for all time intervals except for 1 min (p < 0.05). However, aqueous-phase ozone treatment did not significantly affect the thiol levels (p < 0.05). In conclusion, this study may provide optimum disinfection methods for strawberry to minimize loss of beneficial biothiols.     

Modulation of hepatic drug metabolizing enzymes and oxidative status by rooibos (Aspalathus linearis) and Honeybush (Cyclopia intermedia), green and black (Camellia sinensis) teas in rats

Rooibos and honeybush teas significantly (P < 0.05) enhanced the activity of cytosolic glutathione S-transferase alpha. A significant (P < 0.05) to marginal (P < 0.1) increase in the activity of the microsomal UDP-glucuronosyl transferase was obtained with unprocessed rooibos and honeybush teas, respectively. Oxidized glutathione (GSSG) levels were significantly (P < 0.05) reduced in the liver of all tea treated rats while reduced glutathione (GSH) was markedly increased in the liver of the herbal tea treated rats. These changes resulted in a significant (P < 0.05) increase in the GSH/GSSG ratio by the unprocessed, processed rooibos and unprocessed honeybush teas. Green and black teas markedly to significantly decreased the oxygen radical absorbance capacity in liver homogenates, respectively. Modulation of phase II drug metabolizing enzymes and oxidative status in the liver may be important events in the protection against adverse effects related to mutagenesis and oxidative damage.     

Reduction of ochratoxin a levels in red wine by bentonite, modified bentonites, and chitosan

Adsorption method may play an important role to remove ochratoxin A (OTA) from wine by bentonite (B), nonylammonium bentonite (NB), dodecylammonium bentonite (DB), KSF-montmorillonite (KSF), and chitosan bead (CB). The optimum conditions of OTA adsorption from synthetic solutions were revealed at room temperature and pH 3.5. The adsorption equilibria of B and NB were almost established within 120 and 240 min, respectively. DB, KSF, and CB had about 90 min of equilibration time. The adsorption efficiency carried out in the synthetic OTA solution did not change remarkably when the amounts of adsorbents were 25 mg for bentonite, DB, and KSF and 100 mg for NB and CB. Furthermore, 25 mg of adsorbents was used at all adsorption studies in synthetic solution. The adsorption isotherm was fitted with mostly a Freundlich equation with respect to the correlation coefficients. The adsorption data were evaluated using Langmuir and Freundlich equations having Kf values ranging from 0.011 to 9.5 with respect to correlation coefficients (R2 = 0.900-0.977). DB and KSF have the highest adsorption capacity for OTA in synthetic solutions. In wine, the removal of OTA was succeeded at a percentage of 60-100 by KSF and CB. Furthermore, the highest adsorption capacity of OTA for red wine was obtained by using 250 mg of KSF, which caused less damage to the nature of wine and also low adsorption of polyphenols and anthcyans.     

Correlation of antioxidant capacities to oxygen radical scavenging enzyme activities in blackberry

The activities of the oxygen radical scavenging enzymes [glutathione-peroxidase (GSH-POD), superoxide dismutase (SOD), and guaiacol peroxidase (G-POD)], hydrogen peroxide scavenging enzymes in the ascorbate-glutathione cycle [ascorbate peroxidase (AsA-POD), monodehydroascorbate reductase (MDAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR)], the nonenzyme components [ascorbate (AsA), dehydroascorbate (DHAsA), glutathione (GSH), and oxidized glutathione (GSSG)], and their antioxidant capacity [oxygen radical absorbance capacity (ORAC)] were measured in the juice of six different thornless blackberry (Rubus sp.) cultivars. The 'Hull Thornless' cultivar contained the highest levels, whereas 'Black Satin' consistently had the lowest activities for all the enzymes tested in this study. ORAC values were also the highest in 'Hull Thornless' and lowest in 'Black Satin'. The highest levels of AsA and DHAsA were in the juice of 'Hull Thornless' blackberries with 1. 09 and 0.15 micromol/g fresh wt, respectively. 'Hull Thornless' also had the highest ratio of AsA/DHAsA among the six blackberry cultivars studied. The 'Smoothstem' cultivar contained the lowest amounts of AsA and DHAsA. 'Hull Thornless' had the highest GSH content with 78.7 nmol/g fresh wt, while 'Chester Thornless' contained the largest amount of GSSG. The highest GSH/GSSG ratio was 4.90 which was seen in the 'Hull Thornless' cultivar. The correlation coefficient between ORAC values and AsA/DHAsA ratios was as high as 0.972. A correlation (r = 0.901) was also detected between ORAC values and GSH content. The antioxidant activity in blackberry juice was positively correlated to the activities of most antioxidant enzymes (r = 0.902 with SOD; r = 0.858 with GSH-POD; r = 0.896 with ASA-POD; and r = 0.862 with GR).     

Gentiana manshurica Kitagawa reverses acute alcohol-induced liver steatosis through blocking sterol regulatory element-binding protein-1 maturation

This study was undertaken to investigate the protective effects of Gentiana manshurica Kitagawa (GM) on acute alcohol-induced fatty liver. Mice were treated with ethanol (5 g/kg of body weight) by gavage every 12 h for a total of three doses to induce acute fatty liver. Methanol extract of GM (50, 100, or 200 mg/kg) or silymarin (100 mg/kg) was gavaged simultaneously with ethanol for three doses. GM administration significantly reduced the increases in serum ALT and AST levels, the serum and hepatic triglyceride levels, at 4 h after the last ethanol administration. GM was also found to prevent ethanol-induced hepatic steatosis and necrosis, as indicated by liver histopathological studies. Additionally, GM suppressed the elevation of malondialdehyde (MDA) levels, restored the glutathione (GSH) levels, and enhanced the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities. The concurrent administration of GM efficaciously abrogated cytochrome P450 2E1 (CYP2E1) induction. Moreover, GM significantly reduced the nuclear translocation of sterol regulatory element-binding protein-1 (nSREBP-1) in ethanol-treated mice. These data indicated that GM possessed the ability to prevent ethanol-induced acute liver steatosis, possibly through blocking CYP2E1-mediated free radical scavenging effects and SREBP-1-regulated fatty acid synthesis. Especially, GM may be developed as a potential therapeutic candidate for ethanol-induced oxidative damage in liver.     

Influence of ethanol content on the extent of copigmentation in a cencibel young red wine

The effect of ethanol content on the copigmentation of a Cencibel young red wine was studied, by means of ethanol elimination and reconstitution of the initial volume with different ethanol proportions. The reference wine (14.0% ethanol, 0.40 g/L volatile acidity) showed a bathochromic shift of 4 nm and a color enhancement (DeltaColor) of 41%, lower than that found for the reconstituted wine with the same ethanol content (53%). This discrepancy could be attributable to the loss of acetic acid during the ethanol elimination step. DeltaColor was 95% for the reconstituted wine without ethanol and decreased until 18% for the reconstituted wine with 22% ethanol. Copigmentation was important for reconstituted wines with ethanol contents typical for table red wine, showing DeltaColor between 53 and 57%. An increase in ethanol content in reconstituted wines was accompanied by an increase in the pH value. Perceivable changes in color (DeltaE > 1) followed every increase in ethanol content.     

Apple peel polyphenols protect against gastrointestinal mucosa alterations induced by indomethacin in rats

The stability of an apple peel polyphenol extract (APPE) with powerful antioxidant activity was evaluated under acidic conditions in vitro, and its protective effect against gastrointestinal damage was investigated in rats treated with indomethacin. The antioxidant activity of APPE remained stable at pH 2.0 for 4 h. In rats treated with indomethacin (40 mg/kg ig), the previous administration of APPE protected the gastric, intestinal, and colonic mucosa from oxidative stress by preventing increased malondialdehyde concentrations and decreasing the GSH/GSSG ratio. APPE also displayed anti-inflammatory effects by preventing neutrophil infiltration in the mucosa, as evidenced by the lower myeloperoxidase activity. These protective effects of APPE resulted in the prevention of macro- and microscopic damage and of barrier dysfunction along the gastrointestinal tract of the indomethacin-treated animals. This study supports the concept that apple peel polyphenols may be useful in the prevention and/or treatment of nonsteroidal anti-inflammatory drug-associated side effects.     

Quantitation of ochratoxin A in South African wines

The natural occurrence of the carcinogenic mycotoxin ochratoxin A (OTA) in wines sold in local retail outlets in South Africa and Italy was investigated by HPLC analysis with fluorescence detection following cleanup by immunoaffinity column. All 24 local South African wines tested (15 white and 9 red) were found to contain detectable levels (>0.01 microg/L) of OTA, with a mean of 0.16 microg/L in the white wines and a mean of 0.24 microg/L in the red wines. Results were subsequently confirmed by LC-MS analysis using positive ion electrospray ionization with collision-induced dissociation of the protonated molecular ion [M + H](+) at m/z 404 and selected reaction monitoring of the resultant product ions [M + H - H(2)O - CO](+) at m/z 358 and [M + H - H(2)O](+) at m/z 386. Comparison with the fluorescence method gave a significant correlation (r = 0.87; p < 0.01). Although OTA contamination was present in all of the South African samples analyzed, levels were well below the suggested European Union limit of 0.5 microg/kg. The highest level found in a locally purchased wine was 0.39 microg/L in a blend of local and imported Spanish red wine. Of the eight Italian wines analyzed, only two red wines were contaminated above the suggested maximum level.     

Boron stress,oxidative damage and antioxidant protection in potato cultivars (Solanum tuberosum L.)

Six potato cultivars grown in Turkey in boron-prone areas and differing in their tolerance towards high boron were studied to reveal whether boron causes oxidative stress. To assess stress level, chlorophyll fluorescence and growth parameters were measured. Oxidative damage was assessed as malondialdehyde level, and antioxidant protection was evaluated as ascorbate (AA), dehydroascorbate, reduced glutathione (GSH) and oxidized glutathione amounts and superoxide dismutase, catalase, ascorbate peroxidase (APX) and glutathione reductase (GR) activities. High boron stress affected photosynthesis negatively in a threshold-dependent manner and inhibited growth. No pronounced changes in oxidation of lipids occurred in any cultivar. Activation of APX suggested the involvement of an ascorbic acid–reduced glutathione cycle in the protection against oxidative stress caused by high boron. Efficient work of this antioxidant system was probably hindered by boron complexation with NAD(P)⁺/NAD(P)H and resulted in the inhibition of GR and a decrease in AA and GSH. Hence, oxidative stress associated with high boron is a secondary component of boron toxicity which arises from metabolic changes caused by boron interference with major metabolites. Potato cultivars tolerate excess boron stress well and show damage only in very high boron concentrations. The potato cvs best suited for high boron soils/breeding purposes are cvs Van Gogh and Agria.

Abbreviations: AA: ascorbic acid; APX: ascorbate peroxidase; CAT: catalase; DHA: dehydroascorbic acid; DHAR: dehydroascorbate reductase; DTNB: 5; 5′-dithiobis-2-nitrobenzoic acid; DTT: dithiotreitol; F_v/F_m: photosynthetic efficiency at the dark-adapted state; GR: glutathione reductase; GSH: reduced glutathione; GSSG: oxidized glutathione; MDA: malondialdehyde; ROS: reactive oxygen species; SOD: superoxide dismutase; TCA: trichloroacetic acid     

Simultaneous determination of oxidized and reduced glutathione in eel's (Monopterus albus) plasma by transient pseudoisotachophoresis coupled with capillary zone electrophoresis

Both the reduced form of glutathione (GSH) and the oxidized form of glutathione (GSSG) in eel's ( Monopterus albus) plasma were for the first time determined by transient pseudoisotachophoresis coupled with capillary zone electrophoresis. The method of transient pseudoisotachophoresis coupled with capillary zone electrophoresis has been thoroughly optimized and adequately evaluated for the simultaneous determination of GSH and GSSG in eel's plasma. The detection limits (S/N = 3) of the method developed were 0.2 and 0.05 micromol/L for GSH and GSSG, respectively. The linearity of the calibration curves was valid in the range of 0-10 micromol/L GSH and 0-0.70 micromol/L GSSG. The method was simple, fast, and reproducible. It was found that the respective concentrations of GSH and GSSG were in the range of 9.1-14.5 and 0.31-0.58 micromol/L in the adult eel's plasma, and 10.8-17.9 and 0.49 - 0.68 micromol/L in the juvenile eel's plasma of the three populations determined. Each blood sample was a composite of five eels. For each of the three populations, the concentrations of GSH and GSSG in the adult eel's plasma were lower than those in the juvenile eel's plasma, and the concentrations of GSH and GSSG in the plasma of population 1 (deep yellow finless eels) were higher than those in populations 2 (light yellow finless eels) and 3 (green finless eels) for either the adult or the juvenile eels.     

Distribution of Glutathione in Millstreams and Relationships to Chemical and Baking Properties of Flour

Fourteen millstream flours, a straight‐run flour, bran, pollard, and germ were prepared separately from two Australian and two New Zealand wheat cultivars using a 650 kg/hr pilot roller mill. Glutathione (GSH) and oxidized glutathione (GSSG) were measured in all samples. The Australian cultivars had higher levels of GSH and GSSG than the New Zealand cultivars, and in all cultivars the levels in pollard and germ were considerably higher than in flour samples. Generally, the early break flours and early reduction flours had lower GSSH/GSSG levels than the tail‐end break and reduction flours. There was a strong correlation between GSH/GSSG and ash content in millstream flours, which indicated that much of the GSH/GSSG in the flour was likely to have derived from contamination by bran, aleurone (pollard), and germ. There were also moderate to strong correlations between GSH/GSSG and the cysteine content of all proteins in flour. GSH/GSSG correlated strongly with the albumin and globulin content of flour but not with gliadin and glutenin. The volume and crumb texture properties of bread made with millstream flours in the absence of ascorbic acid (AA) were negatively correlated with GSH/GSSG. The change in bread volume and texture properties when AA was added to dough (baking improver effect of AA), however, were poorly correlated with GSH/GSSG.     

Ochratoxin a contamination in italian wine samples and evaluation of the exposure in the italian population

The scope of this study was to evaluate the exposure of the Italian population to ochratoxin A (OTA) attributable to wine consumption. With this aim 1166 wine samples (773 red wines, 290 white, 75 rose, and 28 dessert wines), collected in 19 different Italian regions and mostly produced between 1988 and 2004, were analyzed for OTA content. The obtained results are reported by year of harvest, geographical area of production, and type of wine. Red wine showed the highest maximum level of contamination (7.50 ng/mL), even though rose wines were characterized by a higher mean value (0.01 ng/mL). A gradually increasing mean concentration was also observed from the north (0.05 ng/mL) to south of Italy (0.54 ng/mL). Exposure calculations, performed using two different consumption databases, indicate a daily intake for consumer only of 0.59 up to 1.24 ng/(kg of b.w.)/day and of 0.33 up to 0.90 ng/(kg of b.w.)/day for the total population. Even in the worst case, corresponding to the calculation of the intake for consumers only in southern Italy and Islands and considering the mean consumption data increased by 1 standard deviation, a quite low exposure (1.68 ng/(kg of b.w.)/day, accounting for 9.8% of TDI) was obtained. Considering the overall OTA dietary exposure, obtained exposure rates indicate that wine did not pose a risk to the Italian population health.     

土霉素对日本锦鲫肝脏抗氧化防御系统的影响

土霉素（Oxytetrac ycline,简称OTC）是养殖业中广泛使用的药物之一,由于大量使用,已在水环境中不断被检出,其对水生生物及人类可能产生的影响已经引起人们广泛关注。采用室内染毒实验方法,研究了土霉素对典型淡水鱼类日本锦鲫肝脏抗氧化防御系统的影响,分析暴露于不同浓度（0、0.01、0.05、0.1、0.5、1.0、5.0、10mg·L-1）的OTC溶液15d后鱼体肝脏中ROS、MDA、SOD、CAT和谷胱甘肽等指标,探讨其潜在的致毒机制。结果表明,ROS信号强度在高浓度组（5mg·L-1和10mg·L-1）与对照相比分别减少44.2%和32.5%,呈显著性差异;MDA含量在0.1mg·L-1和5mg·L-1下显著减少,分别减少41.7%和52.3%;SOD活性在0.01mg·L-1下显著性增加32.4%,CAT和GST活性呈低浓度被诱导、高浓度被抑制的趋势;GSH和GSSG含量的变化趋势相似,呈先减少后增加的趋势（P〈0.05）。上述结果表明低浓度OTC对日本锦鲫产生氧化应激,诱导了肝脏抗氧化防御系统,但高浓度下清除氧自由基的作用大于其氧化应激毒性,从而使得鱼体氧化应激程度减轻。抗氧化防御系统酶活性的变化只能间接反映污染物对生物造成应激效应的程度,要弄清楚OTC的致毒机制仍需进一步研究。     

棉花幼苗AsA-GSH循环对低温胁迫的响应机制研究

为探究棉花幼苗营养器官抗坏血酸-谷胱甘肽(AsA-GSH)循环系统对低温胁迫的响应机制,以新陆早57号为试验材料,研究4℃低温胁迫不同时间(0、1和2 d)对根、茎和叶中抗氧化物质含量和酶活性的影响。结果表明,与对照(0 d)相比,随着低温胁迫时间延长,棉花幼苗根中还原型抗坏血酸(AsA)含量及单脱氢抗坏血酸还原酶(MDHAR)和谷胱甘肽还原酶(GR)活性呈上升趋势,氧化型抗坏血酸(DHA)含量先减少后增加,氧化型谷胱甘肽(GSSG)含量和脱氢抗坏血酸还原酶(DHAR)活性先升高后降低,谷胱甘肽氧化还原状态(GSH/GSSG比率)和抗坏血酸过氧化物酶(APX)活性总体呈下降趋势,抗坏血酸氧化还原状态(AsA/DHA比率)、还原型谷胱甘肽(GSH)含量和谷胱甘肽过氧化物酶(GPX)活性无显著性差异;茎和叶中AsA和GSH含量、AsA/DHA比率及APX、MDHAR和GR活性总体呈上升趋势,且茎中DHAR活性升高,DHA和GSSG含量先减少后增加,GSH/GSSG比率和GPX活性无显著性差异,而叶中DHA含量和GSH/GSSG比率先不变后增加,DHAR活性先升高后降低,GSSG含量和GPX活性无显著性差异。综合分析显示,棉花幼苗通过调节根、茎和叶中抗氧化物质含量和酶活性来清除活性氧,从而适应低温胁迫,减轻低温伤害。此外,低温对根中AsA-GSH循环影响最大。本研究结果为揭示低温胁迫对棉花幼苗AsA-GSH循环代谢机制提供了理论依据。     

不同金属辅基和酶剂量对超氧化物歧化酶抗氧化、促氧化作用的影响

研究含不同类型金属辅基(Mn或Cu,Zn)的超氧化物歧化酶(SOD)的抗氧化/促氧化作用特征,以及酶剂量对其抗氧化/促氧化作用的影响。用化学发光法分析超氧化物歧化酶对由Fenton体系产生的羟基自由基(.OH)导致DNA氧化损伤的影响。进一步利用.OH所致质粒DNA氧化后在琼脂糖凝胶电泳中的构型改变为实验模型,比较不同类型金属辅基和剂量对SOD抗氧化/促氧化活性的影响。Mn-SOD对.OH引起的DNA氧化损伤没有显著影响。然而,Cu,Zn-SOD在较高浓度(>200 U/ml)下,表现出强烈的促氧化效应,能够加剧DNA氧化损伤。研究结果表明,金属辅基对SOD的抗氧化或促氧化效应有着重要的影响,这可能与金属辅基在Fenton反应中的氧化还原特性相关。高浓度的Cu,Zn-SOD对.OH所致DNA氧化损伤存在显著的促氧化效应。高浓度的Mn辅基离子不能与Fenton体系中H2O2直接作用,并且不能促进羟基自由基的形成。     

Model aging and oxidation effects on varietal, fermentative, and sulfur compounds in a dry botrytized red wine

From harvest until wine arrives to the consumer, oxygen plays a crucial role in the definition of the final aroma. In the present research, the effect of the model oxidative aging on a dry red Botrytis wine, such as Italian Amarone, was considered. Amarone wine was submitted to model oxidative aging and then analyzed with two different approaches (SPE-GC-MS and HS-SPME/GC-MS). The same sampling plan was adopted to study the model aging of the same Amarone wine in anaerobic conditions. The HS-SPME/GC-MS method was applied to investigate for the first time the effect of the oxidative aging on a vast number of fermentative sulfur compounds. This research highlighted peculiar evolutions for several volatile compounds. In particular, benzaldehyde showed a sensitive increment during the oxidative aging, with a rate much higher than that reported for non-Botrytis red wines. On the other hand, several sulfides (dimethyl sulfide, 3-(methylthio)-1-propanol, etc.) disappeared after just 15 days of oxidative aging. A wine oxidation marker such as 3-(methylthio)-propanal was not found in any of the oxidized wines; conversely methionol-S-oxide was tentatively identified. This evidence has not been mentioned in the literature. A possible involvement of grape withering process and Botrytis in these mechanisms was supposed: a dry red wine, produced from the same but without any grape withering process and Botrytis infection (e.g., Bardolino wine), was submitted to oxidative aging and analysis. This red wine showed an evolution similar to those reported in the literature for dry red wines but significantly different from the Amarone wine.     

Polyphenols-enriched Chardonnay white wine and sparkling Pinot Noir red wine identically prevent early atherosclerosis in hamsters

The effects of a white wine enriched with polyphenols (PEWW) from Chardonnay grapes and of a sparkling red wine (SRW) from Pinot Noir and Chardonnay grapes were studied for the first time on early atherosclerosis in hamsters. Animals were fed an atherogenic diet for 12 weeks. They received by force-feeding PEWW, SRW, ethanol 12% (ETH), or water as control (mimicking a moderate consumption of approximately 2 red wine glasses per meal for a 70 kg human). Plasma cholesterol concentrations were lower in groups that consumed PEWW and SRW accompanied by an increase in the ratio apo A-1/apo B. Liver-specific activities of superoxide dismutase and catalase were significantly increased by PEWW (38 and 16%, respectively) and by SRW (48 and 15%, respectively). PEWW and ETH significantly increased plasma antioxidant capacity and vitamin A concentrations. Aortic fatty streak area (AFSA) was significantly strongly reduced in the groups receiving PEWW (85%) and SRW (89%) in comparison with the control. AFSA was reduced by ethanol to a lesser extent (58%). These data suggest that tannins from the phenolics-enriched white wine induce a protective effect against early atherosclerosis comparable to that produced by sparkling red wine containing tanins and anthocyanins and dissociated from the antioxidant action of these compounds.