Effect of phenol-rich extra virgin olive oil on markers of oxidation in healthy volunteers

OBJECTIVE: We studied whether consumption of phenol-rich extra virgin olive oil affects the susceptibility of low density lipoproteins (LDL) to oxidation and other markers of oxidation in humans. DESIGN: Randomized cross-over intervention trial, stratified according to sex, age and energy intake. SETTING: Division of Human Nutrition and Epidemiology, Wageningen University, The Netherlands. SUBJECTS: Forty-six healthy men and women completed the study. INTERVENTION: Subjects consumed two diets supplying 69 g per day of extra virgin olive oil either rich or poor in phenols for 3 weeks each. The mean difference in phenol intake between the treatments was 18 mg per day. Vitamin E intake was low during the whole study. Fasting blood samples were taken twice at the end of each period. RESULTS: Resistance of LDL and high density lipoprotein (HDL) to oxidation was not affected by treatment. The mean lag time of copper-induced formation of conjugated dienes was 1.6 min shorter in LDL and 0.4 min longer in HDL after the high phenol diet. Other markers of antioxidant capacity in plasma were also not affected: mean lipid hydroperoxides were 0.07 micromol/l higher, mean malondialdehydes were 0.001 micromol/l higher, mean protein carbonyls were 0.001 nmol/mg protein lower, and the mean ferric reducing ability of plasma (FRAP) was 0.006 mmol/l higher after the high phenol diet. All 95% confidence intervals enclosed zero. Serum cholesterol concentrations were not affected by the treatment. CONCLUSION: Consumption of 18 mg per day of phenols from extra virgin olive oil for 3 weeks did not affect LDL or HDL oxidation or other markers of antioxidant capacity in fasting plasma samples.     

Personal PM2.5 exposure and markers of oxidative stress in blood

Ambient particulate air pollution assessed as outdoor concentrations of particulate matter less than or equal to 2.5 micro m in diameter (PM(2.5)) in urban background has been associated with cardiovascular diseases at the population level. However, the significance of individual exposure and the involved mechanisms remain uncertain. We measured personal PM(2.5) and carbon black exposure in 50 students four times in 1 year and analyzed blood samples for markers of protein and lipid oxidation, for red blood cell (RBC) and platelet counts, and for concentrations of hemoglobin and fibrinogen. We analyzed protein oxidation in terms of gamma-glutamyl semialdehyde in hemoglobin (HBGGS) and 2-aminoadipic semialdehyde in hemoglobin (HBAAS) and plasma proteins (PLAAS), and lipid peroxidation was measured as malondialdehyde (MDA) in plasma. Median exposures were 16.1 micro g/m(3) for personal PM(2.5) exposure, 9.2 micro g/m(3) for background PM(2.5) concentration, and 8.1 X 10(-6)/m for personal carbon black exposure. Personal carbon black exposure and PLAAS concentration were positively associated (p < 0.01), whereas an association between personal PM(2.5) exposure and PLAAS was only of borderline significance (p = 0.061). A 3.7% increase in MDA concentrations per 10 micro g/m(3) increase in personal PM(2.5) exposure was found for women (p < 0.05), whereas there was no significant relationship for the men. Similarly, positive associations between personal PM(2.5)exposure and both RBC and hemoglobin concentrations were found only in women (p < 0.01). There were no significant relationships between background PM(2.5) concentration and any of the biomarkers. This suggests that exposure to particles in moderate concentrations can induce oxidative stress and increase RBCs in peripheral blood. Personal exposure appears more closely related to these biomarkers potentially related to cardiovascular disease than is ambient PM(2.5) background concentrations.     

Effect of parsley (Petroselinum crispum) intake on urinary apigenin excretion, blood antioxidant enzymes and biomarkers for oxidative stress in human subjects

Seven men and seven women participated in a randomized crossover trial to study the effect of intake of parsley (Petroselinum crispum), containing high levels of the flavone apigenin, on the urinary excretion of flavones and on biomarkers for oxidative stress. The subjects received a strictly controlled diet low in flavones and other naturally occurring antioxidants during the 2 weeks of intervention. This basic diet was supplemented with parsley providing 3.73-4.49 mg apigenin/MJ in one of the intervention weeks. Urinary excretion of apigenin was 1.59-409.09 micrograms/MJ per 24 h during intervention with parsley and 0-112.27 micrograms/MJ per 24 h on the basic diet (P < 0.05). The fraction of apigenin intake excreted in the urine was 0.58 (SE 0.16)% during parsley intervention. Erythrocyte glutathione reductase (EC 1.6.4.1; GR) and superoxide dismutase (EC 1.15.1.1; SOD) activities increased during intervention with parsley (P < 0.005) as compared with the levels on the basic diet, whereas erythrocyte catalase (EC 1.11.1.6) and glutathione peroxidase (EC 1.11.1.9) activities did not change. No significant changes were observed in plasma protein 2-adipic semialdehyde residues, a biomarker of plasma protein oxidation. In this short-term investigation, an overall decreasing trend in the activity of antioxidant enzymes was observed during the 2-week study. The decreased activity of SOD was strongly correlated at the individual level with an increased oxidative damage to plasma proteins. However, the intervention with parsley seemed, partly, to overcome this decrease and resulted in increased levels of GR and SOD.     

In vitro and ex vivo anti-inflammatory activity of quercetin in healthy volunteers

OBJECTIVE: Quercetin, a commonly occurring flavonoid and well known antioxidant, has been suggested to possess other beneficial activities. The present study investigated the possible anti-inflammatory effects of physiologically attainable quercetin concentrations. METHODS: The effects of quercetin were tested in vitro, i.e., added to blood in the test tube, and ex vivo and in vivo, i.e., in blood taken after 4 wk of administration of quercetin in an intervention study. RESULTS: Quercetin dose-dependently inhibited in vitro lipopolysaccharide-induced tumor necrosis factor-alpha production in the blood of healthy volunteers. At a concentration of 1 muM, quercetin caused a 23% reduction. The in vitro lipopolysaccharide-induced interleukin-10 production remained unaffected by quercetin. A 4-wk quercetin intervention resulted in a significant increase in plasma quercetin concentration. The supplementation also increased total plasma antioxidant status but did not affect glutathione, vitamin C, and uric acid plasma concentrations. Basal and ex vivo lipopolysaccharide-induced tumor necrosis factor-alpha levels were not altered by the intervention. CONCLUSION: The present study shows that quercetin increases antioxidant capacity in vivo and displays anti-inflammatory effects in vitro, but not in vivo or ex vivo, in the blood of healthy volunteers. This lack of effect is probably due to their low cytokine and high antioxidant levels at baseline, indicating that neither inflammation nor oxidative stress is present. Only in people with increased levels of inflammation and oxidative stress, e.g., patients with a disease of which the pathology is associated with these two processes, might antioxidant supplementation be fruitful.     

液相色谱法测定植物样品中槲皮素和山萘酚

目的:建立HPLC法测定桑叶等植物中槲皮素和山奈酚含量的方法.方法:用甲醇和盐酸混合液水解植物样本中的黄酬类成分为槲皮素和山奈酚,用NaOH调水解液的pH至2～3,用HPLC法测定样本中的槲皮素和山奈酚含量.结论:此法可用于植物中的槲皮素和山奈酚的分离及测定,且方法简单,重现性好.     

Effects of safflower seed extract supplementation on oxidation and cardiovascular risk markers in healthy human volunteers

We previously demonstrated that safflower seed extract (SSE) and its major antioxidant constituents, serotonin hydroxycinnamic acid amides, suppressed LDL oxidation in vitro, decreased plasma autoantibody titres to oxidized LDL and attenuated atherosclerotic lesion formation in apoE-deficient mice. In this report, we examined whether SSE, rich in serotonin derivatives, could affect markers of oxidative stress, inflammation and aortic stiffness in healthy human subjects. Twenty Japanese male volunteers were studied at baseline, after 2.1 g SSE supplementation daily (providing 290 mg serotonin derivatives/d) for 4 weeks, and after a 4-week washout period. Significant reductions in circulating oxidized LDL, autoantibody titres to malondialdehyde-modified LDL, the soluble form of vascular cell adhesion molecule-1 (sVCAM-1), and urinary 8-isoprostane were observed after a 4-week intervention. Although there were no statistically significant differences in blood pressure or brachial-ankle pulse wave velocity (baPWV), an index of arterial stiffness, baPWV was lower than baseline in eleven of twenty subjects and was accompanied by a reduction in blood pressure. Statistically significant negative correlations were observed between the extent of initial cardiovascular risk markers (autoantibody titres, 8-isoprostane, sVCAM-1 and baPWV) and the effect of intervention. This suggested that individuals with elevated oxidative stress, inflammation, and/or arterial stiffness may receive more benefit from SSE supplementation.     

Effect of dietary quercetin on oxidative DNA damage in healthy human subjects

The effect of dietary intake of flavonols (predominantly quercetin) on oxidative DNA damage was studied in thirty-six healthy human subjects (sixteen men, twenty women). The study was a randomised crossover study, comprising two 14 d treatments of either a low-flavonol (LF) or high-flavonol (HF) diet with a 14 d wash-out period between treatments. Subjects were asked to avoid foods containing flavonols, flavones and flavanols during the LF dietary treatment period and to consume one 150 g onion (Allium cepa) cake (containing 89.7 mg quercetin) and one 300 ml cup of black tea (containing 1.4 mg quercetin) daily during the HF dietary treatment. A 7 d food diary was kept during each dietary period and blood samples were taken after each dietary treatment. Products of oxidative damage to DNA bases were measured in DNA from leucocytes. The study had more than 95% power to detect a change of 20% in DNA damage products Plasma vitamin C and plasma quercetin concentrations were also measured. No significant differences in intake of macronutrients or assessed micronutrients, measured DNA base damage products, or plasma vitamin C were found between the HF and LF dietary treatments. The plasma quercetin concentration was significantly higher after the HF dietary treatment period (228.5 (SEM 34.7) nmol/l) than after the LF dietary treatment period (less than the limit of detection, i.e. <66.2 nmol/l). These findings do not support the hypothesis that dietary quercetin intake substantially affects oxidative DNA damage in leucocytes.     

Red wine consumption prevents vascular oxidative stress induced by a high-fat meal in healthy volunteers

In order to investigate the effect of red wine on plasma lipid and oxidative stress parameters after a high-fat meal, fifteen healthy volunteers were studied: three days after a high-fat meal with 250 mL of water, they received the same meal with 250 mL of red wine. During both periods, serial blood samples were drawn before and 2, 4, and 8 hours after the meal to evaluate plasma lipids (cholesterol and triglycerides; retinyl palmitate), oxidative stress (D-ROM, and malondialdehyde) and antioxidant (total plasma antioxidant levels and uric acid) parameters. During the meal without wine, plasma lipid parameters increased significantly, whereas plasma total plasma antioxidant levels decreased, and a trend toward reduction of uric acid levels was seen). A similar trend in lipid parameters was observed after the meal with wine; no significant difference in individual lipid parameter trends after a meal with and without wine was observed. Wine ingestion induced higher total plasma antioxidant levels and uric acid; malondialdehyde levels remained constant after wine ingestion. Plasma D-ROM showed a significant postprandial increase in both experiments, but it was significantly lowered after wine ingestion. Our results give evidence of oxidative stress following a fat-rich meal in healthy subjects, suggesting that ingestion of red wine during a high-fat meal significantly reduces oxidative stress without inducing any significant modification in postprandial lipemia.     

Effects of Mediterranean diets with low and high proportions of phytate-rich foods on the urinary phytate excretion

Background  

Important health benefits have been reported recently to phytate intake. This includes the prevention of pathological calcifications such as renal calculi, dental calculi and cardiovascular calcification, due its action as crystallization inhibitor of calcium salts, and as preventive of cancer.     

Content of ascorbic acid,quercetin, kaempferol and total phenolics in commercial broccoli

A total of 80 commercial broccoli samples were collected over a two-year period to determine seasonal variation in the levels of ascorbic acid (AA), vitamin C (the sum of AA and dehydroascorbic acid [DHAA]), the predominant flavonoids quercetin and kaempferol, and total phenolics at the consumer level. Levels of AA and vitamin C varied between 13.37–110.30 and 57.35–131.35 mg/100 g fresh weight (FW), respectively. The levels of quercetin and kaempferol ranged from 0.03 to 10.85 and 0.24 to 13.20 mg/100 g FW, respectively. Total phenolic activity ranged from 48.15 to 157.77 mg/100 g FW. Significant seasonal variation and year-to-year variability were observed in the content of all phytochemicals examined. Total phenolic levels correlated positively with levels of vitamin C, quercetin, and kaempferol. Based upon the USDA/ERS 2007 database for consumption based upon sales, and the data reported herein, the daily availability of vitamin C from broccoli was estimated at 8.99 mg; accounting for 15% of Reference Daily Intake (RDI). The average daily availability of quercetin, kaempferol and total phenolics from broccoli was estimated as 0.23, 0.32 and 5.50 mg, respectively.     

槲皮素固体分散体对小鼠四氯化碳急性肝损伤氧化应激的影响

目的 研究槲皮素固体分散体对小鼠四氯化碳(CCl4)急性肝损伤氧化应激的影响.方法 槲皮素固体分散体给予小鼠连续灌胃7d,通过腹腔注射CCl4诱导小鼠急性肝损伤,计算肝指数,测定小鼠血清中谷丙转氨酶(GPT)、谷草转氨酶(GOT)水平及肝匀浆中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性和丙二醛(MDA)含量,观察肝组织病理学变化.结果 槲皮素固体分散体能降低CCl4致肝损伤小鼠肝指数,降低血清中GPT和GOT水平,提高肝组织中SOD和GSH-Px活性,降低MDA含量,明显改善肝组织损伤程度.结论 槲皮素固体分散体对小鼠CCl4急性肝损伤具有保护作用,并能减轻小鼠肝损伤氧化应激反应.     

Effects of fish oil- and olive oil-rich diets on iron metabolism and oxidative stress in the rat

The objective of the present study was to examine the effects of fish oil (FO)- and olive oil (OO)-rich diets on Fe metabolism and oxidative stress. Rats were fed for 16 weeks with diets containing 50 g lipids/kg; either OO, maize oil (MO) or FO. OO or MO diets contained a standard amount (100 mg/kg) of all-rac-alpha-tocopheryl acetate. FO diets were supplemented with 0, 100 or 200 mg all-rac-alpha-tocopheryl acetate/kg (FO-0, FO-1 or FO-2 diets, respectively). At the end of the feeding period, we measured non-haem Fe stores in liver and spleen, and erythrocyte and reticulocyte count. We also determined antioxidants and products derived from lipid peroxidation in plasma and erythrocytes. Our results showed reduced non-haem Fe stores in rats fed any of the FO diets. Reticulocyte percentage was higher in the rats fed FO-0 and FO-1. Plasma alpha-tocopherol was very low in rats fed the FO-0 diet. Rats fed the FO-1 and FO-2 diets showed higher alpha-tocopherol in plasma than the FO-0 group but lower than the MO or OO groups. We did not observe such differences in the alpha-tocopherol content in erythrocyte membranes. Superoxide dismutase and glutathione peroxidase activities were lower in the erythrocytes of rats fed the FO-0 diet. The products derived from lipid peroxidation were also higher in the FO groups. The administration of FO-rich diets increased lipid peroxidation and affected Fe metabolism. On the other hand, the OO-rich diet did not increase oxidative stress and did not alter Fe metabolism. Based on these results, we conclude that FO supplementation should be advised carefully.     

Effects of creatine supplementation on oxidative stress and inflammatory markers after repeated-sprint exercise in humans

ObjectiveThe goal of this study was to evaluate the effects of creatine (Cr) supplementation on oxidative stress and inflammation markers after acute repeated-sprint exercise in humans.MethodsTwenty-five players under age 20 y were randomly assigned to two groups: Cr supplemented and placebo. Double-blind controlled supplementation was performed using Cr (0.3 g/kg) or placebo tablets for 7 d. Before and after 7 d of supplementation, the athletes performed two consecutive Running-based Anaerobic Sprint Tests (RAST). RAST consisted of six 35-m sprint runs at maximum speed with 10 sec rest between them. Blood samples were collected just prior to start of test (pre), just after the completion (0 h), and 1 h after completion.ResultsAverage, maximum, and minimum power values were greater in the Cr-supplemented group compared with placebo (P < 0.05). There were significant increases (P < 0.05) in plasma tumor necrosis factor alpha (TNF-α) and C-reactive protein (CRP) up to 1 h after acute sprint exercise in the placebo-supplemented group. Malondialdehyde, lactate dehydrogenase (LDH), catalase, and superoxide dismutase enzymes also were increased after exercise in both groups. Red blood cell glutathione was lower after exercise in both groups. Cr supplementation reversed the increase in TNF-α and CRP as well as LDH induced by acute exercise. Controversially, Cr supplementation did not inhibit the rise in oxidative stress markers. Also, antioxidant enzyme activity was not different between placebo and Cr-supplemented groups.ConclusionCr supplementation inhibited the increase of inflammation markers TNF-α and CRP, but not oxidative stress markers, due to acute exercise.     

Effects of short-term moderate alcohol administration on oxidative stress and nutritional status in healthy males

The effects of moderate amounts of different alcoholic beverages on oxidative stress and nutritional parameters were investigated in 40 healthy subjects. Ethanol 40 g/day was administered at the two main meals for 30 days by beer (group A), wine (group B) or spirit (group C); controls (group D) maintaned abstinence. Malondyaldeide (MDA), adenosine-triphosphate (ATP), reduced-glutathione (GSH), E-vitamin and nutritional status were evaluated at the start (T0) and the end (T1) of the study. At T1 controls did not present significant changes in the assessed parameters, while a significant increase of malondyaldeide (MDA) and a significant decrease of reduced-glutathione and E-vitamin in group A, B and C and of ATP in group C were observed. Fat mass (FM) increased slightly in group A and B and decreased in group C. Ethanol decreased antioxidant parameters and increased lipoperoxidation parameters. However some of these changes appeared attenuated when ethanol was consumed in beer or wine. Finally, short-term moderate ethanol intake appeared to influence the FM, although it was not able to significantly affect nutritional or body composition.     

Effect on blood pressure of two diets differing in total fat but not in saturated and polyunsaturated fatty acids in healthy volunteers

The effects of a low-fat, carbohydrate-rich and a high-fat, olive-oil-rich diet on blood pressure were studied under strict dietary control. Forty-seven healthy normotensive men and women were fed a diet high in saturated fatty acids (20 en%) and total fat (38 en%) for 17 d. Twenty-four subjects then received a low-fat, carbohydrate-rich diet (total fat 22 en%) and the other 23 a high-fat, olive-oil-rich diet (oleic acid 24 en%, total fat 41 en%) for 36 d. Both test diets had the same level of saturated fatty acids (7-10 en%) and linoleic acid (4 en%). Systolic blood pressure fell by 2.3 and diastolic by 4.7 mm Hg in the carbohydrate group and by 2.7 and 4.4 mm Hg in the olive-oil group, respectively (differences between diets groups not significant). These results suggest that a high-fat diet rich in monounsaturated fatty acids has no deleterious effect on blood pressure in healthy normotensive subjects in comparison with a low-fat, carbohydrate-rich diet.     

Case-control study of markers of oxidative stress and metabolism of blood iron in Parkinson's disease

BACKGROUND: Increasingly growing evidence exists of the involvement of oxidative stress mechanisms in Parkinson's disease. Lower levels of GSH in the sustantia nigra, an increase in iron buildup, an increase in the byproducts of lipid peroxidation and alterations in the mitochondrial complex I have been described. However, few studies have been made of levels of antioxidants in the peripheral bloodstream and of the influence of the intake of nutrients on the development of this disease. METHODS: In a group of 79 patients afflicted with idiopathic Parkinson's disease and a control group comprised of 107 subjects, compared by age, sex and place of residence, the lowered levels in the plasma of glutathione (GSH), malon dialdehyde (MDA), uric acid, tocophenol, beta-carotene, lycopene and different iron metabolism parameters were studied. Likewise, the intake of certain antioxidants was estimated based on a dietary survey. RESULTS: Significant differences (p < or = 0.001) were found in the plasma levels of GSH between cases (0.10 mumol/ml +/- 0.06) and controls (0.29 mumol/ml +/- 0.12). Likewise, the plasma levels of uric acid were lower (p < or = 0.05) in the cases (4.96 mg/ml +/- 1.96) than in the control groups (5.39 mg/ml +/- 1.13). No significant difference was found in the plasma levels of MDA, tocopherol, beta-carotene and lycopene. With regard to iron metabolism, significantly higher ferritine and transferrin values were found in the patients with EP than in the control group, showing a lower transferrin saturation percentage (p < or = 0.05). The iron showed no significant changes between cases and control groups. CONCLUSIONS: The results of this study support the possible involvement of oxidative stress in the pathogenesis of Parkinson's disease and reveal, in turn, alterations in some peripheral blood parameters in keeping with known findings in the sustantia nigra.     

The influence of moderate red wine consumption on antioxidant status and indices of oxidative stress associated with CHD in healthy volunteers

The effects of moderate red wine consumption on the antioxidant status and indices of lipid peroxidation and oxidative stress associated with CHD were investigated. A randomised, controlled study was performed with twenty free-living healthy volunteers. Subjects in the red wine group consumed 375 ml red wine daily for 2 weeks. We measured the total concentration of phenolics and analysed the individual phenolics in the wine and plasma by HPLC with tandem MS. The antioxidant capacity of plasma was measured with electron spin resonance spectroscopy while homocysteine and fasting plasma lipids were also determined. The production of conjugated dienes and thiobarbituric acid-reactive substances (TBARS) were measured in Cu-oxidised LDL. Plasma total phenolic concentrations increased significantly after 2 weeks of daily red wine consumption (P< or =0.001) and trace levels of metabolites, mainly glucuronides and methyl glucuronides of (+)-catechin and (-)-epicatechin, were detected in the plasma of the red wine group. These flavan-3-ol metabolites were not detected in plasma from the control group. The maximum concentrations of conjugated dienes and TBARS in Cu-oxidised LDL were reduced (P< or =0.05) and HDL cholesterol concentrations increased (P< or =0.05) following red wine consumption. The findings from the present study provide some evidence for potential protective effects of moderate consumption of red wine in healthy volunteers.     

Zero effect of multiple dosage of olive leaf supplements on urinary biomarkers of oxidative stress in healthy humans

ObjectiveWe determined the effect of dietary supplementation with an olive leaf capsule or liquid extract on oxidative status of young and healthy male and female subjects.MethodsThis was a single-center, randomized, single-blinded, prospective pilot comparison of the effect of dietary supplementation with olive leaf extracts. Healthy young adult male and female subjects (n = 45) were randomized into three groups and received daily doses of control, capsule, or liquid extract of olive leaf. Urinary F_2α-isoprostane, 8-hydroxy-2′-deoxyguanosine, and Folin-Ciocalteu total reducing power were measured to assess the impact of supplementation.ResultsBaseline values (mean ± standard deviation) of the biomarkers were 0.24 ± 0.13 μg, 9.16 ± 2.94 μg, and 424.9 ± 121.4 mg of gallic acid equivalents per gram of creatinine, respectively, for the control group. Using these markers, supplementation with liquid or capsule did not alter oxidative status compared with the control group. Possible reasons for the lack of an observed correlation are presented.ConclusionDietary supplementation with olive leaf extract did not alter the oxidative status of healthy young adults.     

Vitamin C and fibre consumption from fruits and vegetables improves oxidative stress markers in healthy young adults

The aim of the present cross-sectional study was to assess the potential relationships between fruit and vegetable (FV) consumption and some oxidative stress markers in young adults, with particular emphasis on fibre and vitamin C intake. The study enrolled 246 healthy subjects (eighty-eight men and 158 women), with a mean age of 22 (sd 3) years and a mean BMI of 21·9 (sd 2·8) kg/m2. Dietary intake, anthropometry, blood pressure, lifestyle features and blood biochemical data were assessed with validated procedures. Those subjects in the highest tertile (T) of FV consumption ( ≥ 705 g/d) had statistically lower oxidised LDL (ox-LDL) concentrations as well as higher plasma total antioxidant capacity (TAC) and glutathione peroxidase (GPx) activity (P for trend <0·05), after adjusting for sex, age, energy intake, physical activity, smoking, BMI, vitamin supplement use and other confounding factors. Moreover, plasma ox-LDL concentrations showed a decreasing trend and TAC an increasing trend across tertiles of fibre (T3: ≥14 g/d) and vitamin C (T3: ≥150 mg/d) from FV intake, while GPx activity was positively associated with vitamin C intake (P for trend < 0·05). In conclusion, greater FV consumption was independently associated with reduced ox-LDL as well as increased TAC and GPx activity in healthy young adults, with dietary fibre and vitamin C from FV clearly being implicated in this beneficial relationship.