Dietary intake of natural antioxidants: vitamins and polyphenols

Nutritional Solutions to Reduce Risks of Negative Health Impacts of Air Pollution

Air pollution worldwide has been associated with cardiovascular and respiratory morbidity and mortality, particularly in urban settings with elevated concentrations of primary pollutants. Air pollution is a very complex mixture of primary and secondary gases and particles, and its potential to cause harm can depend on multiple factors—including physical and chemical characteristics of pollutants, which varies with fine-scale location (e.g., by proximity to local emission sources)—as well as local meteorology, topography, and population susceptibility. It has been hypothesized that the intake of anti-oxidant and anti-inflammatory nutrients may ameliorate various respiratory and cardiovascular effects of air pollution through reductions in oxidative stress and inflammation. To date, several studies have suggested that some harmful effects of air pollution may be modified by intake of essential micronutrients (such as B vitamins, and vitamins C, D, and E) and long-chain polyunsaturated fatty acids. Here, we review the existing literature related to the potential for nutrition to modify the health impacts of air pollution, and offer a framework for examining these interactions.

Estimated Dietary Polyphenol Intake and Major Food and Beverage Sources among Elderly Japanese

Estimating polyphenol intake contributes to the understanding of polyphenols' health benefits. However, information about human polyphenol intake is scarce, especially in the elderly. This study aimed to estimate the dietary intake and major sources of polyphenols and to determine whether there is any relationship between polyphenol intake and micronutrient intake in healthy elderly Japanese. First, 610 subjects (569 men, 41 women; aged 67.3 ± 6.1 years) completed food frequency questionnaires. We then calculated their total polyphenol intake using our polyphenol content database. Their average total polyphenol intake was 1492 ± 665 mg/day, the greatest part of which was provided by beverages (79.1%). The daily polyphenol intake differed largely among individuals (183-4854 mg/day), also attributable mostly to beverage consumption. Coffee (43.2%) and green tea (26.6%) were the major sources of total polyphenol; the top 20 food items accounted for >90%. The polyphenol intake did not strongly correlate with the intake of any micronutrient, suggesting that polyphenols may exert health benefits independently of nutritional intake. The polyphenol intake in this elderly population was slightly higher than previous data in Japanese adults, and beverages such as coffee and green tea contributed highly to the intake.

An exploration of the antioxidant effects of garlic saponins in mouse-derived C2C12 myoblasts

In this study, we aimed to confirm the protective effects of garlic saponins against oxidative stress-induced cellular damage and to further elucidate the underlying mechanisms in mouse-derived C2C12 myoblasts. Relative cell viability was determined by 3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide assay. Comet assay was used to measure DNA damage and oxidative stress was determined using 2',7'-dichlorofluorescein diacetate to measure intracellular reactive oxygen species (ROS) generation. Western blot analysis and small interfering RNA (siRNA)-based knockdown were used in order to investigate the possible molecular mechanisms. Our results revealed that garlic saponins prevented hydrogen peroxide (H2O2)-induced growth inhibition and exhibited scavenging activity against intracellular ROS. We also observed that garlic saponins prevented H2O2-induced comet tail formation and decreased the phosphorylation levels of γH2AX expression, suggesting that they can prevent H2O2-induced DNA damage. In addition, garlic saponins increased the levels of heme oxygenase-1 (HO-1), a potent antioxidant enzyme associated with the induction and phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the translocation of Nrf2 from the cytosol into the nucleus. However, the protective effects of garlic saponins on H2O2-induced ROS generation and growth inhibition were significantly reduced by zinc protoporphyrin Ⅸ, an HO-1 competitive inhibitor. In addition, the potential of garlic saponins to mediate HO-1 induction and protect against H2O2‑mediated growth inhibition was adversely affected by transient transfection with Nrf2-specific siRNA. Garlic saponins activated extracellular signal‑regulated kinase (ERK) signaling, whereas a specific ERK inhibitor was able to inhibit HO-1 upregulation, as well as Nrf2 induction and phosphorylation. Taken together, the findings of our study suggest that garlic saponins activate the Nrf2/HO-1 pathway by enabling ERK to contribute to the induction of phase Ⅱ antioxidant and detoxifying enzymes, including HO-1 in C2C12 cells.

Comparison of antioxidant activity between green and roasted coffee beans using molecular methods

Coffee is one of the most popular and widely consumed beverages worldwide due to its pleasant taste and aroma. A number of studies have been performed to elucidate the possible beneficial effects of coffee consumption on human health and have shown that coffee exhibits potent antioxidant activity, which may be attributed mainly to its polyphenolic content. However, there is also evidence to suggest that coffee roasting (the procedure which turns green coffee beans to the dark, roasted ones from which the beverage derives) may alter the polyphenolic profile of the beans (e.g., via the Maillard reaction) and, concomitantly, their antioxidant activity. In the present study, the antioxidant activity of 13 coffee varieties was examined in both green and roasted coffee bean extracts using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-eth-ylbenzothiazoline-6-sulfonic acid) (ABTS^•+) radical scavenging assays. In addition, 5 selected varieties were also examined for their protective effects against peroxyl and hydroxyl radical-induced DNA strand cleavage. Finally, C2C12 murine myoblasts were treated with non-cytotoxic concentrations of the most potent extract in order to examine its effects on the cellular redox status by measuring the glutathione (GSH) and reactive oxygen species (ROS) levels by flow cytometry. Our results revealed that, in 8 out of the 13 coffee varieties, roasting increased free radical scavenging activity as shown by DPPH and ABTS^•+ assays. Moreover, we found that when one coffee variety was roasted for different amounts of time, the increase in the antioxidant activity depended on the roasting time. By contrast, in 5 varieties, roasting reduced the antioxidant activity. Similar differences between the roasted and green beans were also observed in the free radical-induced DNA strand cleavage assay. The observed differences in the antioxidant activity between the different coffee varieties may be attributed to their varying polyphenolic content and composition, as well as to the different molecules produced during roasting. In addition, in the cell culture assay, the tested coffee extract led to increased GSH levels in a dose-dependent manner, indicating the enhancement of cellular antioxidant mechanisms.

Normal or High Polyphenol Concentration in Orange Juice Affects Antioxidant Activity, Blood Pressure, and Body Weight in Obese or Overweight Adults

BACKGROUND

The consumption of orange juice may lead to reduced oxidative stress and may enhance the antioxidant defense system.

OBJECTIVE

The aim was to evaluate the effects of the intake of orange juice containing either normal (NPJ) or high (HPJ) concentrations of polyphenols (299 and 745 mg/d, respectively) on the antioxidant defense system, oxidative stress biomarkers, and clinical signs of metabolic syndrome in 100 nonsmoking subjects who were either overweight or obese.

METHODS

A randomized, double-blind crossover study was conducted over two 12-wk periods with a 7-wk washout period. The effects on enzymatic and nonenzymatic blood antioxidant defense systems, urinary and plasma oxidative stress biomarkers, and clinical signs of metabolic syndrome were evaluated before and after an intervention with both of the orange juices. Paired t tests and linear mixed-effects models were used to evaluate the effects of juice, time, and interactions.

RESULTS

The intake of either NPJ or HPJ led to a decrease in urinary 8-hydroxy-2'-deoxyguanosine (NPJ: 935 ± 134 to 298 ± 19 ng/mg creatinine; HPJ: 749 ± 84 to 285 ± 17 ng/mg creatinine), 8-iso-prostaglandin F2α (NPJ: 437 ± 68 to 156 ± 14 ng/mg creatinine; HPJ: 347 ± 43 to 154 ± 13 ng/mg creatinine), erythrocyte catalase, and glutathione reductase activities. A decrease was also observed in body mass index, waist circumference, and leptin (all P < 0.05). The NPJ intervention decreased systolic and diastolic blood pressures (systolic blood pressure: 128 ± 1 to 124 ± 2 mm Hg; diastolic blood pressure: 79 ± 1 to 76 ± 1 mm Hg), whereas the HPJ intervention increased erythrocyte superoxide dismutase (SOD) activity (17.7 ± 1.5 to 23.1 ± 1.7 U/mg hemoglobin).

CONCLUSIONS

Our results show that the consumption of either NPJ or HPJ protected against DNA damage and lipid peroxidation, modified several antioxidant enzymes, and reduced body weight in overweight or obese nonsmoking adults. Only blood pressure and SOD activity were influenced differently by the different flavanone supplementations. This trial was registered at clinicaltrials.gov as NCT01290250.

Antioxidant vitamin intake and mortality in three Central and Eastern European urban populations: the HAPIEE study

PURPOSE

The aim of the study was to assess the relationships between individual-level dietary intakes of antioxidant vitamins C, E and beta-carotene with all-cause and cause-specific mortality in three Central and Eastern European (CEE) populations.

METHODS

Data from the Health, Alcohol and Psychosocial factors in Eastern Europe cohort study were used. At the baseline survey, between 2002 and 2005, 28,945 men and women aged 45-69 years were examined in Novosibirsk (Russia), Krakow (Poland) and seven Czech towns. Deaths in the cohorts were identified through mortality registers. Cox regression was used to estimate the association between vitamin consumption and all-cause, cardiovascular (CVD) disease and cancer mortality.

RESULTS

In multivariable-adjusted analyses, there were no clear inverse associations between antioxidant vitamin intakes and mortality, although in some groups, several hazard ratios (HRs) were significant. For example, in men, compared with the lowest quintile of vitamin C intake, all-cause mortality in the third and fourth quintiles was lower by 28 % (HR 0.72; 95 % CI 0.61-0.85) and by 20 % (HR 0.80; 95 % CI 0.68-0.95), respectively. CVD mortality was lower by 35 % (HR 0.65; 95 % CI 0.50-0.84) and by 23 % (HR 0.77; 95 % CI 0.59-0.99) in third and fourth quintile of vitamin C intake, respectively. In women, the third and fourth quintiles of dietary intake of vitamin E were associated with reduced risk of all-cause death by 33 % (HR 0.67; 95 % CI 0.53-0.84) and by 23 % (HR 0.77; 95 % CI 0.61-0.97), respectively. Consumption of vitamin C, vitamin E and beta-carotene was not related to CVD mortality in women and to cancer mortality in either gender.

CONCLUSION

This large prospective cohort study in CEE populations with low prevalence of vitamin supplementation did not find a strong, dose-response evidence for protective effects of antioxidant vitamin intake.

Effects of GSTM1/GSTT1 gene polymorphism and fruit & vegetable consumption on antioxidant biomarkers and cognitive function in the elderly: a community based cross-sectional study

Background

It was reported that Glutathione S-transferase (GST) gene polymorphism and fruit and vegetable (FV) intake were associated with body antioxidant capacity. The oxidative/anti-oxidative imbalance played an important role in the pathogenesis of AD. However, the association of GST genotype, dietary FV consumption with body antioxidant biomarkers and cognitive function in the elderly is not clear.

Objective

The aim of the present study was to determine the association of GST genotype, and dietary FV intake, with antioxidant biomarkers and cognitive function in the elderly.

Methods

Food frequency questionnaire was used to collect data of dietary FV intakes in 504 community dwelling elderly aged from 55 to 75 years old. GSTM1 and GSTT1 genotypes were determined by using multiple-PCR method. Plasma and erythrocyte antioxidant biomarkers were measured. Cognitive function was measured by using Montreal Cognitive Assessment. Statistical analysis was applied for exploring the association of GST genotype and FV intake with antioxidant biomarkers level and cognitive function in the elderly.

Results

Individual GSTM1 or GSTT1 gene deletion affects body antioxidant biomarkers levels, including erythrocyte GST activity, plasma total antioxidant capacity, and glutathione levels. GSTM1and/or GSTT1 gene deletion have no effects on cognitive function in the surveyed participants. The effect of GST genotype on antioxidant biomarkers are FV intake dependent. There is interaction of FV intake and GST genotype on cognitive function in the elderly.

Conclusion

GST genotype or daily FV consumption impact body antioxidant biomarkers, but not cognitive function in the elderly. There were combined effects of GST genotype and FV consumption on cognitive function in the elderly population. Large scale perspective population study is required to explore the association of GST genetic polymorphism, FV consumption and antioxidant biomarkers and cognitive function in the elderly.

Protection of Clitoria ternatea flower petal extract against free radical-induced hemolysis and oxidative damage in canine erythrocytes

The present study assessed the antioxidant activity and protective ability of Clitoria ternatea flower petal extract (CTE) against in vitro 2,2'-azobis-2-methyl-propanimidamide dihydrochloride (AAPH)-induced hemolysis and oxidative damage of canine erythrocytes. From the phytochemical analysis, CTE contained phenolic compounds, flavonoids, and anthocyanins. In addition, CTE showed antioxidant activity as measured by oxygen radical absorbance capacity (ORAC) method and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. CTE (400 µg/ml) remarkably protected erythrocytes against AAPH-induced hemolysis at 4 h of incubation. Moreover, CTE (400 µg/ml) reduced membrane lipid peroxidation and protein carbonyl group formation and prevented the reduction of glutathione concentration in AAPH-induced oxidation of erythrocytes. The AAPH-induced morphological alteration of erythrocytes from a smooth discoid to an echinocytic form was effectively protected by CTE. The present results contribute important insights that CTE may have the potential to act as a natural antioxidant to prevent free radical-induced hemolysis, protein oxidation and lipid peroxidation in erythrocytes.

Preparation of organogel with tea polyphenols complex for enhancing the antioxidation properties of edible oil

Food-grade organogels are semisolid systems with immobilized liquid edible oil in a three-dimensional network of self-assembled gelators, and they are supposed to have a broad range of potential applications in food industries. In this work, an edible organogel with tea polyphenols was developed, which possesses a highly effective antioxidative function. To enhance the dispersibility of the tea polyphenols in the oil phase, a solid lipid-surfactant-tea polyphenols complex (organogel complex) was first prepared according to a novel method. Then, a food-grade organogel was prepared by mixing this organogel complex with fresh peanut oil. Compared with adding free tea polyphenols, the organogel complex could be more homogeneously distributed in the prepared organogel system, especially under heating condition. Furthermore, the organogel loading of tea polyphenols performed a 2.5-fold higher antioxidation compared with other chemically synthesized antioxidants (butylated hydroxytoluene and propyl gallate) by evaluating the peroxide value of the fresh peanut oil based organogel in accelerated oxidation conditions.

Analysis of oxidative stress in zebrafish embryos

High levels of reactive oxygen species (ROS) may cause a change of cellular redox state towards oxidative stress condition. This situation causes oxidation of molecules (lipid, DNA, protein) and leads to cell death. Oxidative stress also impacts the progression of several pathological conditions such as diabetes, retinopathies, neurodegeneration, and cancer. Thus, it is important to define tools to investigate oxidative stress conditions not only at the level of single cells but also in the context of whole organisms. Here, we consider the zebrafish embryo as a useful in vivo system to perform such studies and present a protocol to measure in vivo oxidative stress. Taking advantage of fluorescent ROS probes and zebrafish transgenic fluorescent lines, we develop two different methods to measure oxidative stress in vivo: i) a "whole embryo ROS-detection method" for qualitative measurement of oxidative stress and ii) a "single-cell ROS detection method" for quantitative measurements of oxidative stress. Herein, we demonstrate the efficacy of these procedures by increasing oxidative stress in tissues by oxidant agents and physiological or genetic methods. This protocol is amenable for forward genetic screens and it will help address cause-effect relationships of ROS in animal models of oxidative stress-related pathologies such as neurological disorders and cancer.

Release of antioxidant capacity from five plant foods during a multistep enzymatic digestion protocol

This study aimed at elucidating the influence of food matrix on the release of antioxidant activity from five plant foods (apple, spinach, walnut, red bean, and whole wheat). To this purpose a protocol based on sequential enzymatic digestion was adopted. The total antioxidant capacity (TAC) of both solubilized and insoluble materials was measured at each step. Results showed that the overall TAC obtained by enzyme treatments was usually higher than that obtained by chemical extraction-based methods. In apple most of the TAC was released upon water washing and after pepsin treatment, whereas in spinach, beans, and whole wheat the TAC released by treatments with bacterial enzymes was prominent. Walnut had the highest TAC value, which was mainly released after pancreatin treatment. Therefore, the enzyme treatment is fundamental to estimate the overall potential TAC of foods having a high amount of polyphenols bound to dietary fiber or entrapped in the food matrix.

Effect of hydrothermal processing on total polyphenolics and antioxidant potential of underutilized leafy vegetables, Boerhaavia diffusa and Portulaca oleracea

OBJECTIVE

To investigate the effect of different processing methods on antioxidant properties of acetone extract of aerial parts from Boerhaavia diffusa and Portulaca oleracea.

METHODS

The total phenolic and flavonoid contents were determined by Folin-Ciocalteau and aluminum chloride method, respectively. FRAP, metal chelating activity, DPPH, ABTS, nitric oxide, hydroxyl and superoxide radical scavenging activities, carotene/linoleic acid bleaching activity were used for the determination of antioxidant capacity.

RESULTS

The total phenolics in Boerhaavia diffusa (82.79-162.80 mg GAE/g extract) were found to be higher when compared to that of Portulaca oleracea (22.94-10.02 mg GAE/g extract). Hydrothermal processing enhanced the level of inhibition on synthetic radicals such as DPPH (3 439-309 549 mmol TE/g extract) and ABTS (17 808-53 818 mmol TE/g extract) as well as biologically relevant radicals such as superoxide anion (70%-90%) and nitric oxide (49%-57%). In addition, boiling of the vegetables were found to be maximum capacity of FRAP (6 404.95 mmol Fe (II)/g extract) and metal chelating activity (1.53 mg EDTA/g extract) than the respective raw samples.

CONCLUSIONS

The present investigation suggests that the processing enhance the functionality and improves the availability of bioactive substances of these vegetables. In addition, they also exhibited more potent antioxidant activity. Therefore these natural weeds from the crop land ecosystem could be suggested as cost effective indigenous green vegetables for human diet and potential feed resources for animals. Further extensive studies on role and importance of those weeds in sustaining the agro biodiversity are also needed.

Association of fruits and vegetables consumption and related-vitamins with inflammatory and oxidative stress markers in prediabetic individuals

BACKGROUND

Dietary guidelines of 5 servings per day of fruits and vegetables (FV) offer a reasonable amount of vitamins to control organic processes, which may contribute to a favorable cardiometabolic profile. This study aimed at investigating whether the intake of the FV group as well as pro-vitamin A carotenoids and vitamins C and E were associated with circulating markers of oxidative stress, inflammation and insulin resistance in Brazilians individuals at cardiometabolic risk.

METHODS

This cross-sectional study included 205 individuals screened for diabetes prevention program in a healthcare center from the School of Public Health, University of São Paulo, conducted in 2008. Possible associations of consumption of FV group, as well as pro-vitamin A carotenoids and vitamins C and E, with circulating markers of oxidative stress (superoxide dismutase - SOD and oxidized LDL - oxLDL), inflammation (C reactive protein, TNF-α and adiponectin) and insulin resistance (HOMA-IR) were investigated. Pearson correlation coefficient, ANOVA and multiple linear regression were employed.

RESULTS

The sample (64.7% women) had a mean age of 54.1 ± 12.7 years and body mass index of 30.7 ± 5.7 kg/m2. Dietary, physical activity, anthropometric and laboratory data were obtained. Participants consumed a mean of 3.8 servings/day of FV; their FV intake was categorized into three groups: <2.5, 2.5-5.0 and >5.0 servings/day. Significant trends for lower waist circumference (103.4 ± 13.6 vs. 100.1 ± 12.2 vs. 98.2 ± 12.7 cm, p-trend <0.05) and higher adiponectin concentrations (10.4 ± 1.8 vs. 11.9 ± 1.9 vs. 13.6 ± 2.1 ng/mL, p-trend <0.05) were detected across categories. Associations between SOD concentrations (β 0.172 [0.110-0.688]) with FV consumption and between oxLDL concentrations with vitamins C (β -0.333 [-2.568 - -0.218]) and E (β -0.354 [-1.131- -0.110]) intakes, adjusted for age, gender, BMI, saturated fat intake, smoking and physical activity were found. Similar results were observed for the associations between oxLDL and FV intake, but significance disappeared adding adjustment for saturated fat, smoking and physical activity.

CONCLUSION

Our data suggest that the intake of FV or selected vitamins may be useful for identifying the oxidative stress and inflammation involved in the genesis of cardiometabolic diseases and for motivating at-risk patients for changing dietary habits.

Protective Effect of Alpha-Lipoic Acid on Cypermethrin-Induced Oxidative Stress in Wistar Rats

Cypermethrin (CY), a class II pyrethroid pesticide, is globally used to control insects in the household and in agriculture. Despite beneficial roles, its uncontrolled and repetitive application leads to unintended effects in non-target organisms. In light of the relevant anti-oxidant properties of alpha-lipoic acid (ALA), in the work described herein we tested the effect of a commercially available ALA formulation on cypermethrin (CY)-induced oxidative stress in Wistar rats. The rats were orally administered with 53.14 mg/kg of ALA and 35.71 mg/kg of CY for 60 days. The treatment with CY did not induce changes in either locomotor activities or in body weight. Differences were observed on superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation that were re-established by ALA treatment at similar levels of the placebo group. Furthermore, ALA formulation increased glutathione (GSH) level and glutathione peroxidase (GPx) activity. Because of the widespread use of CY, higher amounts of pesticide residues are present in food, and a diet supplementation with ALA could be an active free radical scavenger protecting against diseases associated with oxidative stress.