Total phenolics and antioxidant capacity of indigenous vegetables in the southeast United States: Alabama Collaboration for Cardiovascular Equality Project

Collard greens, mustard greens, kale, okra, green onion, butter beans, butter peas, purple hull peas, rutabagas, and eggplant are frequently consumed by African Americans in the southeast United States. Sweet potato greens and purslane are two novel vegetables in this region. The objective of this study was to analyze total phenolics and antioxidant capacity in these indigenous vegetables. The total phenolic content was analyzed using the Folin-Ciocalteu method and ranged from 7.4 to 53.5 mg gallic acid equivalents per gram of dried sample. The antioxidant capacity was analyzed using the radical DPPH(?) scavenging capacity assay and oxygen radical absorbance capacity assay (ORAC). At a concentration of 10.0 mg dried vegetable equivalent/ml, the extract of these vegetables was able to quench 13.2-88.5% DPPH(?) radical in 30 min. The ORAC value ranged from 2.5 to 100.7 μmoles of trolox equivalents per gram of dried sample. The antioxidant capacity of the vegetable samples was highly related to their total phenolic content. The results suggest that these indigenous vegetables consumed by African Americans in the southeastern United States are good sources of the phenolic compounds, which might provide anti-oxidative protection against free radicals in the human body. Consumption of these vegetables might reduce the risk of chronic diseases.     

Increasing antioxidant intake from fruits and vegetables: practical strategies for the Scottish population

Background Increasing intakes of dietary antioxidants may help to reduce oxidative damage caused by free radicals and provide protection against the progression of a number of chronic diseases. The present study aimed to estimate the antioxidant intake from fruits and vegetables in the UK and Scottish population and to examine consumption models to identify potential strategies to optimize antioxidant intake from these foods. Methods This was a retrospective study of cross‐sectional data on fruit and vegetable intake in relation to antioxidant intake. Antioxidant capacity of individual fruits and vegetables was determined by the ferric reducing antioxidant power assay and data on quantity and frequency of consumption of fruits and vegetables determined from National Diet and Nutrition Survey 2000–2001. Results Mean antioxidant intake in UK population from fruits and vegetables varied by region. In the Scottish sample (n = 123), mean antioxidant intake was estimated at 680 ± 689 μmol day^?1 with 92% subjects consuming <400 g of fruits and vegetables per day. Consumption data showed that strawberries, apples, orange citrus fruits, purple broccoli and cauliflower were the top five sources of antioxidants from fruits and vegetables in the Scottish population. Conclusions Appropriate selection of fruits and vegetables would help to achieve a higher antioxidant intake with the potential to produce significant health benefits.     

苯对大鼠总抗氧化能力的影响

目的 探讨苯对大鼠总抗氧化能力（Total antioxidant capacity,TAC）的影响。方法 应用化学比色法检测大鼠血清中TAC含量,同时利用直接计数法计数大鼠全血白细胞（WBC）总数。结果 苯使染毒大鼠血清TAC含量明显降低,与WBC计数结果一致。结论 TAC水平的改变可能是苯毒性作用的重要方面。     

Effect of different cooking methods on the polyphenol concentration and antioxidant capacity of selected vegetables

The objective of this study was to evaluate the effect of different methods of cooking on the concentration of polyphenols and antioxidant capacity found in vegetables. Squash, broccoli, carrots, kale, cabbage, green beans, and tomato were submitted to different cooking methods and then compared with their fresh form. Heat treatment was shown to have a significant effect on the antioxidant capacity and soluble and hydrolysable polyphenolic content of most vegetables analyzed, either increasing or decreasing the concentration of these compounds. The results suggest that the best cooking method for increasing the concentration of polyphenols and antioxidants was steaming, while microwave cooking was the least recommended method.     

Influence of cultivation sites on sterol,nitrate, total phenolic contents and antioxidant activity in endive and stem chicory edible products

Chicories produce a wide range of vegetables with important nutritional value. We determined the variation of sterol, total polyphenol, nitrate contents and antioxidant capacity (SC, TPC, NC, AC) in endive leaves and stem-chicory novel vegetables, cultivated in two Italian regions. Within a given area, the SC was similar in smooth- and curly leafed endives (106.3–176.0?mg/kg FW); sitosterol and stigmasterol were major fractions (45–56 versus 38–43%). The stem SC was independent of landrace (101.5–118.6?mg/kg FW); sitosterol prevailed on stigmasterol and fucosterol (73–76 versus 12–14% versus 8–9%); the latter reached 15.7?mg/kg FW, conferring value as potential antidiabetes food. The planting site affected the AC and TPC of endives (893.1–1571.4 μmTE/100?g FW, 30.8–76.1 GAE100/g FW) and chicory stems (729.8–1152.5 μmTE/100?g FW; 56.2–124.4 GAE100/g FW), while the NC was recurrently below dangerous thresholds. PCA showed that environment was the major cause of variation, though it modestly affected these parameters.     

Total antioxidant capacity of the Korean diet

BACKGROUND/OBJECTIVES

The objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet.

MATERIALS/METHODS

Eighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC).

RESULTS

Total phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 µmol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each.

CONCLUSIONS

The content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables.     

Exogenously applied abscisic acid to Yan73 (V. vinifera) grapes enhances phenolic content and antioxidant capacity of its wine

Yan73 is a ‘teinturier’ red wine variety cultivated in China and widely used in winemaking to strengthen red wine colour. The objective of this study was to evaluate the effect of exogenous abscisic acid (ABA) applied to the grapevine cluster on the antioxidant capacity and phenolic content of the wine made from Yan73. Two hundred mg/l ABA was applied on Yan73 grapevine cluster during veraison. As they mature, these ABA-treated and untreated grape berries were transformed into wines, respectively, and the phenolic content and antioxidant capacity of these wines were compared. The results showed that phenolic content (total phenolics, tannins, flavonoids and anthocyanins) and antioxidant capacity were higher in the wine produced with ABA-treated Yan73 grapes than those in the wine from untreated grapes. Compared to Cabernet Sauvignon wine, Yan73 wine had higher phenolic content and stronger antioxidant capacity. These strongly suggest that exogenously applied ABA to Yan73 grapes can enhance phenolic content and antioxidant capacity of its wine, and Yan73 wine has the higher utilization value and potential for development.     

The use of total antioxidant capacity as surrogate marker for food quality and its effect on health is to be discouraged

Attempts have been made to use non-compositional parameters, such as total antioxidant capacity (TAC), determined by assays such as oxygen radical absorbance capacity, ferric-reducing ability of plasma, and trolox-equivalent antioxidant capacity, as surrogate markers for food quality and for monitoring food-related changes in human plasma in dietary intervention studies. Increased TAC of plasma is often indiscriminately, and therefore incorrectly, interpreted as being favorable to human health. Whether or not dietary compounds may indeed exert health effects depends on factors other than mere presence in food or body fluids. Many phytochemicals, for example, are poorly absorbed and rapidly metabolized into molecules with altered physicochemical, and therefore biological, properties. Consequently, the use of TAC assays for the in vitro assessment of antioxidant quality of food, which often is employed as a marketing argument or for the assessment of the “wholesomeness” of food, is to be discouraged.     

Dietary total antioxidant capacity and obesity in children and adolescents

Background Dietary antioxidant intake has been suggested to protect against oxidative damage and related clinical complications. The aim of the present study was to assess the potential relationships between the dietary total antioxidant capacity (TAC) and obesity-related features in children and adolescents.

Materials and methods Anthropometric variables from 369 children and adolescents were measured (184 obese and 185 control). A validated food-frequency questionnaire was used to calculate the TAC and the daily nutrient and energy intake.

Results Dietary TAC showed positive associations with fiber, folic acid, magnesium, and vitamins A, C and E. The body mass index, standard deviation score of body mass index and total body fat were inversely associated with dietary TAC only in obese subjects.

Conclusion These data suggest that dietary TAC may be a potential indicator of the risk to develop obesity-related features and could be considered a useful method in assessing antioxidant intake.     

Low energy and carbohydrate intake associated with higher total antioxidant capacity in apparently healthy adults

ObjectivesThe aim of this study was to investigate the associations between plasma total antioxidant capacity (TAC) and anthropometric, biochemical, clinical, and dietary measurements in young and apparently healthy individuals.MethodsWe evaluated 156 individuals (91 women and 65 men; ages 23.1 ± 3.5 y; body mass index 22 ± 2.9 kg/m²) for anthropometrics, biochemical markers, clinical, dietary, and some components of the antioxidant defense system, including the plasma TAC. Statistical analyses were performed to detect differences between individuals with TAC higher and lower than the mean value and to screen the associations between TAC and variables of interest. A linear regression model was fitted to identify TAC predictors.ResultsDaily caloric intake and macronutrient consumption were lower in individuals who exhibited the highest TAC values (P < 0.05). Linear regression analysis showed that daily calories and carbohydrate intake was a possible negative TAC predictor (P < 0.05). Nevertheless, there was no difference in the values of oxidized low-density lipoprotein in the individuals separated by means of TAC. In contrast, individuals whose plasma TAC values were above the mean showed higher low-density lipoprotein cholesterol concentrations, total cholesterol/high-density lipoprotein cholesterol values, and selenium in nails (P < 0.05).ConclusionsIn physiological conditions, the caloric intake level seems to be an important factor to act in the modulation of plasma TAC, before establishing anthropometric impairments of body or metabolic composition, or both. Additionally, the plasma TAC increase may be able to act as a compensatory mechanism.     

Effect of fruit and vegetable antioxidants on total antioxidant capacity of blood plasma

For a long time, the increased consumption of fruits and vegetables was considered critical in protecting humans against a number of diseases, such as cancer, diabetes, neurodegenerative diseases, and heart and brain vascular diseases. Presently, it is thought that the protective properties of these foods result from the presence of low-molecular antioxidants that protect the cells and their structures against oxidative damage. The alleged effect of reducing the risk for many diseases is not only due to the effect of individual antioxidants, such as α-tocopherol, ascorbic acid, or β-carotene, but also may be the result of antioxidant compounds not yet known or synergy of several different antioxidants present in fruits and vegetables. Studies on macromolecules (DNA, nucleotides, proteins) free-radical–related damage showed that diets enriched with extra servings of fruits and vegetables rich in β-carotene, tocopherols, and ascorbic acid had only limited effect on the inhibition of oxidation processes. A number of studies have shown, however, that consuming less common fruits and vegetables contribute much more to the reduction of free-radical processes, most likely because they contain a large amount of non-vitamin antioxidants, such as polyphenols and anthocyanins.     

From seed to cooked pasta: influence of traditional and non-conventional transformation processes on total antioxidant capacity and phenolic acid content

The aim of this work was to compare the traditional with a non-conventional (i.e. kernel micronisation) durum wheat milling process by monitoring the content of bound, conjugated and free phenolic acids (PAs) and the level of the total antioxidant capacity (TAC) occurring in the durum wheat pasta production chain, from seed to cooked pasta. The traditional transformation processes negatively influenced TAC and PA content (40% and 89% decrease from seed to cooked pasta, respectively), mainly during the milling process (25% and 84% decrease of TAC and PA, respectively), which has been related to the removal of external layers of kernels. Conversely, the micronisation applied on durum wheat kernels allowed to obtain whole-wheat pasta that preserved the seed endowment of antioxidant compounds even in cooked pasta. These results indicate the micronisation as a valuable approach to produce pasta with improved nutritional value and potential health-promoting effects compared to the traditional pasta.     

Variety-based variation in the antimutagenic potential of various vegetables and lack of its correlation with their antioxidant capacity

As mutation causes many life-threatening diseases including cancer, a diet enriched with specific vegetables having potential to reduce mutagenesis possesses immense significance. In this study, 41 commonly used vegetables from diverse botanical taxa were evaluated and compared for their relative antimutagenic potential using standard assays [Escherichia coli RNA polymerase β (rpoB)-based Rif^S → Rif^R assay and Ames test] against known mutagens (UV, gamma radiation, 4-nitroquinoline-N-oxide and ethylmethanesulphonate). Significant differences in antimutagenicity were observed even among the cultivars within the same species, as well as at other phylogenetic levels such as genus or family. The effect of cooking in terms of boiling (aquathermal treatment), on the antimutagenicity of these vegetables, was also investigated. In majority of the cases, aquathermal treatment did not affect the antimutagenic potential. The antimutagenicity of these vegetables was not found to correlate well with their antioxidant properties.     

几种生物活性物质体外抗氧化能力评价技术的研究

目的研究生物活性物质体外抗氧化能力评价方法,应用体外理化环境下建立起来的评价方法对受试物进行初步抗氧化能力评估。方法联合应用2,2’-连氮-双-(3-乙基苯并噻唑-6-磺酸)二铵盐(ABTS)法与铁离子还原/抗氧化能力测定法(FRAP)法用于生物活性物质体外抗氧化能力研究,在ABTS法中,使用紫外可见分光光度计734nm波长下测定以槲皮素、姜黄素、DL-α-生育酚和原花青素等为代表的生物活性物质;在FRAP法中,运用酶标仪,595nm波长处测定同样受试物的抗氧化能力。结果ABTS法:槲皮素和姜黄素的抗氧化活性TEAC值分别约为2.02和0.50;而1gDL-α-生育酚、原花青素清除自由基的能力相当于2.06mmol、2.897mmol的Trolox清除自由基的能力;FRAP法:抗氧化活性以1.0mmol/L FeSO4为参考标准,槲皮素、姜黄素和Trolox摩尔当量约为5.73、1.18和2.09;而DL-α-生育酚和原花青素抗氧化活性分别是207.7mg、156.36mg。结论ABTS法与FRAP法联合应用,操作简便、结果可靠,尤其适宜作为生物活性物质体外抗氧化能力的评价方法。     

Analysis of phytochemical contributors to antioxidant capacity of the peel of Chinese mandarin and orange varieties

Abstract

The phytochemicals in the peel of six oranges and ten mandarins including seven wild varieties and three cultivars were systematically characterised using UHPLC-Q-TOF-MS, and the correlation analysis was performed between phytochemicals and antioxidant capacity in order to investigate the phytochemical contributors to antioxidant capacity. The gradient elution was completed within 16?min and 92 compounds were undoubtedly or tentatively identified. Furthermore, the antioxidant capacities were determined using ABTS, DPPH and FRAP methods. The number of compounds, their contents and the antioxidant capacities were sequenced in the same order of the wild mandarins?>?cultivated mandarins?>?oranges. The correlation analysis that showed five compounds were significantly correlated with the antioxidant capacity and can act as main contributors to the citrus varieties with high antioxidant capacities. This study is systematic for the metabolites identification of mandarins and oranges and provides valuable information for effective utilisation of citrus peel and their bioactive compounds.     

In vitro studies of polyphenol compounds,total antioxidant capacity and other dietary indices in a mixture of plants (Prolipid)

The best health and nutrition results can be achieved not only from the consumption of fruits and vegetables with high antioxidant capacities, but also from medicinal plants and herbs. Therefore, in the present investigation, the bioactive compounds (polyphenols and flavonoids) and the radical scavenging capacities of Prolipid, a mixture of herbs, were studied. Water extracts showed relatively high capacity of about 61.5% inhibition with the β-carotene–linoleic acid assay. In order to support the data obtained with β-carotene–linoleic acid assay, three different antioxidant assays were used: ferric-reducing/antioxidant power, trolox equivalent antioxidant capacity, and 1,1-diphenyl-2-picrylhydrazyl radical with prolonged time of their reactions. It was found that the amounts of polyphenols in water and methanol extracts were 22.849±2.267 and 3.241±0.325 mg gallic acid equivalent/g dry weight, and the antioxidant capacities in same extracts as determined by the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) test after 120min were 275.81±27.58 and 62.25±6.11 micromole Trolox equivalents (µMTE) dry weight, respectively. The correlation coefficients between polyphenols and antioxidant capacities of Prolipid with 1,1-diphenyl-2-picrylhydrazyl radical and β-carotene–linoleic acid assay were about 0.97 and 0.98. In conclusion, the bioactivity of Prolipid was high and the total polyphenols were the main contributors to the overall antioxidant capacity. The results of our investigation in vitro are comparable with other medicinal plants and fruits widely used in the treatment of humans without known side effects. Prolipid, a mixture of herbs, can therefore be used as a supplement for nutritional and healthy purposes.     

Bioaccessibility of flavonoids and total phenolic content in onions and its relationship with antioxidant activity

Antioxidant activity, total phenolic content, and flavonoids in onion were determined using the DPPH method, the Folin–Ciocalteu method, and high-performance liquid chromatography analysis, respectively. Myricetin was the most bioaccessible among flavonoids in both red and yellow onions after digestion. The result suggest that the antioxidant activity of yellow and red onions was stronger in the outer layer than in the inner layer and strong correlation was found between antioxidant activity and total phenolic content (r² = 0.927).     

Determination of several families of phytochemicals in different pre-cooked convenience vegetables: effect of lifetime and cooking

Phytochemicals content, including several families such as phenolic acids, isoflavones, flavones, flavonols, isothiocyanates, and glucosinolates, was determined in pre-cooked convenience vegetables by ultra high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS). It was observed that there is not a common behavior of the individual concentration of phytochemicals during the lifetime and cooking of the matrix, and compounds change their concentration without a specific trend. It was observed that neither lifetime nor cooking process have significant effects on the total content of phytochemicals except in broccoli, although some changes in the individual content of the target compounds were observed, suggesting that interconversion processes could be performed during the lifetime and/or cooking process of the product.     

Influence of storage and in vitro gastrointestinal digestion on total antioxidant capacity of fruit beverages

Eight fruit beverages containing grape, orange and apricot, with/without iron and/or zinc and with/without milk added were analyzed for total antioxidant capacity (ORAC and TEAC methods), ascorbic acid content, and total polyphenols. The influence of cold storage (2-4 °C) during the product shelf-life (135 days) and antioxidant capacity after an in vitro gastrointestinal digestion were evaluated. Antioxidant capacity for all beverages together increased significantly (p < 0.05) at the end of storage (16.4% and 12.8% for ORAC and TEAC, respectively), whereas ascorbic acid remained stable. Regarding in vitro digestion, antioxidant values of bioaccessible fractions of fruit beverages increased (p < 0.05) 59% and 20% for ORAC and TEAC, respectively, while ascorbic acid and polyphenol content fell 36% and 16%, respectively (p < 0.05). Supplementation of fruit beverages with milk and/or Fe/Zn did not modify total antioxidant capacity of samples during either cold storage or during in vitro digestion.     

Development and validation of an algorithm to establish a total antioxidant capacity database of the US diet

Abstract

Estimation of total antioxidant intake is the first step to investigate the protective effects of antioxidants on oxidative stress-mediated disease. The present study was designed to develop an algorithm to estimate total antioxidant capacity (TAC) of the US diet. TAC of individual antioxidants and 50 popular antioxidant-rich food items in the US diet were determined by 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) assay and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Theoretical TAC of foods was calculated as the sum of individual antioxidant capacities of compounds. The top 10 TAC food items in the US diet according to standard serving size were blueberry > plum > green tea > strawberry > green tea (decaffeinated) > red wine > grape juice > black tea > cherry > grape. Major contributors to TAC were the total phenolic content (r = 0.952, P < 0.001) and flavonoid content (r = 0.827, P < 0.001) of 50 foods. Theoretical TAC was positively correlated to experimental TAC of 50 foods determined by the ABTS assay (r = 0.833, P < 0.001) and the DPPH assay (r = 0.696, P < 0.001), and to TAC from the USDA database for the oxygen radical absorbance capacity (r = 0.484, P = 0.001, n = 44). The TAC database of the US diet has been established and validated. In future studies, TAC of the US diet can be linked to biomarkers of chronic disease.