Hydrophilic Antioxidant Capacity Research Articles

The role of antioxidants in ischaemia-reperfusion in a human DIEP flap model

A better understanding of the pathophysiology of ischaemia-reperfusion injury and a possible treatment for it, is of great importance. The deep inferior epigastric perforator (DIEP) flap is an innovative, clinical model of ischaemia-reperfusion. There has been an ongoing interest in the health benefits and medical applications of antioxidants. We hypothesised that during ischaemia-reperfusion, specific antioxidants are depleted. Seventeen DIEP flaps were performed in 15 patients undergoing breast reconstruction. In each free flap, 3-mm skin biopsies were taken from the DIEP flap at four different time points during and after surgery. In those tissue biopsies, concentrations of the antioxidants vitamin E, glutathione (GSH) and uric acid and total antioxidant capacity (TEAC) were measured. Unexpectedly, no immediate change was observed in GSH concentrations during ischaemia-reperfusion. Uric acid concentrations were significantly increased at all time points following reperfusion. Vitamin E concentrations also showed a significant incline 30min and 1h after reperfusion. However, 1h after reperfusion, a significant decrease in total hydrophilic antioxidant capacity (TEAC) was seen. In the next hour, this capacity recovered. During ischaemia-reperfusion, a deficiency in hydrophilic antioxidant capacity develops. This is a potential cause for the development of ischaemia-reperfusion injury by reactive oxygen species. This clinical trial is registered on Clinical Trials: http://www.clinicaltrials.gov/. Trial registry name: The DIEP-flap as a model of ischaemia-reperfusion. Registration identification number (NCT): 00482469.

DNA damage in peripheral blood mononuclear cells of patients undergoing anti-tuberculosis treatment

Tuberculosis (TB), a chronic infectious disease, is a major cause of morbidity and mortality worldwide. Expression of iNOS and consequent production of NO during the inflammatory process is an important defense mechanism against TB bacteria. We have tested whether pulmonary TB patients undergoing anti-tuberculosis treatment present DNA damage, and whether this damage is related to oxidative stress, by evaluating total hydrophilic antioxidant capacity and iNOS expression. DNA damage in peripheral blood mononuclear cells from patients and healthy tuberculin test (PPD) positive controls was evaluated by single-cell gel electrophoresis (comet assay), and iNOS expression was measured by qPCR. We also evaluated total hydrophilic antioxidant capacity in plasma from patients and controls. Compared to controls, pulmonary TB patients under treatment presented increased DNA damage, which diminished during treatment. Also, the antioxidant capacity of these individuals was increased at the start of treatment, and reduced during treatment. TB patients showed lower iNOS expression, but expression tended to increase during treatment. Our results indicate that pulmonary TB patients under anti-TB treatment exhibit elevated DNA damage in peripheral blood mononuclear cells. This damage was not related to nitric oxide but may be due to other free radicals.

Antioxidant capacity of tomato paste is stable during growing season and shelf‐life

Few data exist regarding the effect of growing season and shelf life on the stability of the antioxidant capacity of foods. To assess these factors in commercially available tomato paste, the sum of lipophilic and hydrophilic antioxidant capacity [oxygen radical absorbance capacity (ORAC), Brunswick Laboratories, Norton, MA] was measured in composite samples comprised of production lots prepared from tomatoes harvested during early, middle, and late growing season periods early in their shelf life (± 6 months) and at 12 and 18 months post‐production. All composites comprised 12 individual consumer units from the same production lot and where measured in duplicate. ORAC for tomato paste produced from early growing season tomatoes was 1341 (μmole Trolox equivalents/100 g). Values for composites made from tomatoes from middle and late growing season harvest were 109% and 118% greater, respectively. Compared to composites measured within 6 months post‐production, ORAC values were 105% and 109% greater at 12 and 18 months post‐production, respectively. These data demonstrate neither within season growing period, nor storage time, adversely affects the antioxidant capacity of tomato paste.Supported by ConAgra Foods

Effects of Pulsed Electric Fields on the Bioactive Compound Content and Antioxidant Capacity of Tomato Fruit

The effect of moderate intensity pulsed electric fields (MIPEF) on the bioactive compounds (total polyphenol, lycopene, and vitamin C content) as well as on the antioxidant capacity of tomato fruit was studied. The MIPEF treatment conditions were optimized to obtain tomato fruit with a high content of bioactive compounds. Tomato fruits were subjected to different electric field strengths (from 0.4 to 2.0 kV/cm) and number of pulses (from 5 to 30) and then immediately refrigerated at 4 °C for 24 h. A concentration of bioactive compounds higher than that of untreated tomatoes was obtained in MIPEF-treated tomatoes. A 44% increase in total polyphenol content was achieved under 30 pulses at 1.2 kV/cm. The hydrophilic antioxidant capacity was also enhanced by 44% applying 18 pulses at 1.2 kV/cm, and the lipophilic antioxidant capacity was increased by 37% under 5 pulses at 1.2 kV/cm. The maximum overall level of bioactive compounds and antioxidant capacity in the treated tomatoes was obtained under 16 pulses at 1 kV/cm. Therefore, MIPEF treatments could be considered an effective method to enhance the bioactive compound content and antioxidant potential of tomatoes.

Stability of the Phenolic and Carotenoid Profile of Gazpachos during Storage

Gazpacho is a ready-to-use vegetable soup containing tomato, cucumber, pepper, olive oil, and other minor constituents such as onion, garlic, wine vinegar, sea salt, and water. In this work, changes in individual phenolic and carotenoid compounds of commercial gazpachos, as well as in their hydrophilic and lipophilic antioxidant capacities (measured through ABTS+ and DPPH radicals), were assessed for 3 months at 4 °C. The storage of gazpachos at 4 °C for 3 months results in a slight decrease in their polyphenol and carotenoid content and also in the hydrophilic and lipophilic antioxidant capacities, but the levels achieved could not be construed as a nutritional drawback. The main degradation was quercetin oxidation because the hydroxy function at the C-ring of the flavonoid is not blocked by a sugar moiety as it is in the case of rutin and kaempferol-3-O-rutinoside and glycosylated caffeic and ferulic acids. Lycopene underwent significant losses throughout storage as 11 conjugated double bonds are present in its structure and should be more reactive than trans-lutein and trans-β-carotene. cis-Lycopene isomers slightly decreased. However, 5-cis-lycopene underwent a slight increase. This phenomenon could be explained by cis-isomerization increasing the proportion of cis-isomers.

Effect of tomato industrial processing on phenolic profile and hydrophilic antioxidant capacity

Industrial processing of tomatoes involves juice addition and heat treatment that may affect (increase or decrease) the levels of phenolic compounds. In this work, we evaluated the effect of each processing step in the paste-making process. Four technological processes were investigated on an industrial scale: Hot Break 28/30, Hot Break 22/24, Cold Break 28/30 and Passata 10/12; and four stages were monitored in each process: (1) fresh tomatoes; (2) juice after scalders and cream addition; (3) tomato paste from evaporators and (4) final paste. The effect of each processing stage was evaluated by different analyses: first, hydrophilic antioxidant capacity was evaluated using ABTS+ and DPPH assays and total phenolics using Folin–Ciocalteau method; then, individual polyphenols were quantified using HPLC-ESI-MS/MS. This multifaceted approach has revealed that each processing stage induces different changes in the antioxidant and phenolic profile. The results of this study indicated that cream addition increases the hydrophilic antioxidant capacity and the amount of phenolic compounds positively, while heat treatment and, to a lesser extent, the sterilization stage during the paste-making process affect these compounds negatively.

Changes in Phenolic Content of Tomato Products during Storage

The effect of storage on the total polyphenol content and individual phenolic compounds as well as on the hydrophilic antioxidant capacity of ketchups and tomato juices was studied. The total polyphenol content was determined using the Folin-Ciocalteu assay, and the antioxidant capacity of the hydrophilic fraction was determined using DPPH and ABTS(+) assays. Individual polyphenols were identified and quantified using liquid chromatography/electrospray ionization tandem mass spectrometry on a triple quadrupole. All analyses were carried out for ketchups and tomato juices after storage for 3, 6, and 9 months. The total polyphenol content and antioxidant capacity of the hydrophilic fraction decreased during storage of ketchups and tomato juices. Ketchups, in general, showed a slightly greater stability during storage than tomato juices. The most significant decrease was observed for quercetin followed by caffeic and ferulic acids, whereas glycosilated polyphenols showed greater stability during storage.

Is there any difference between the phenolic content of organic and conventional tomato juices?

The present study aims to compare the phenolic and hydrophilic antioxidant profiles of organically and conventionally produced tomato juices. Comparisons of analyses of archived samples from conventional and organic production systems demonstrated statistically higher levels (P<0.05) of phenolic compounds in organic tomato juices. This increase corresponds not only with increasing amounts of soil organic matter accumulating in organic plots but also with reduced manure application rates once soils in the organic systems had reached equilibrium levels of organic matter. Using principal component analysis, results show that phenolic compounds and hydrophilic antioxidant capacity were responsible for the differentiation between organic and conventional tomato juices. Thus, there appear to be genuine differences in the bioactive components of organic and conventional tomato juices not previously reported.

Phenolic Profile and Hydrophilic Antioxidant Capacity as Chemotaxonomic Markers of Tomato Varieties

Tomatoes (Solanum lycopersicum L.), the second most important vegetable crop worldwide, are a key component in the so-called "Mediterranean diet", which is strongly associated with a reduced risk of chronic degenerative diseases. In this work, we evaluate the differences in the total and individual polyphenol content and hydrophilic antioxidant capacity of seven varieties of tomato cultivated in Vegas Bajas del Guadiana, Badajoz (Spain), which were collected from two consecutive harvests (2008-2009). Hydrophilic antioxidant capacity was evaluated using the TEAC assay, while the Folin-Ciocalteau assay with a previous cleanup was used to establish total polyphenol content. The method was optimized and validated. Individual polyphenols were quantified using liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) on a triple quadrupole. All compounds were found to be significantly different when analysis of variance was performed. Results from the principal component analysis show that phenolic compounds and hydrophilic antioxidant capacity were responsible for the differences among tomato samples according to variety.

HPLC profiling of phenolics in diverse potato genotypes

Potatoes from over fifty genotypes representing cultivars, breeding lines, primitive germplasm and wild species were analysed for phenolic content and hydrophilic antioxidant capacity. Genotypes with markedly higher amounts than the most commonly consumed potatoes were identified. Chlorogenic acid was the most abundant phenolic and ranged from 22 to 473mg/100gdryweight. Rutin and kaempferol-3-rutinose were the most abundant flavonols. Total phenolics ranged from 1.8 to 11mg/gDW and antioxidant capacity ranged from 27 to 219μmolTE/gDW. Total phenolics and antioxidants in these high-phytonutrient potatoes compared favourably to 15 other analysed vegetables. With the high per capita consumption of potatoes, widespread adoption of high-phytonutrient cultivars could significantly increase dietary intake of phytonutrients.

Hydrophilic and lipophilic antioxidant capacity of commonly consumed South African fruits, vegetables, grains, legumes, fats/oils and beverages

The antioxidant capacity of commonly consumed South African foods was determined using the fluorescein (FL)-based oxygen radical absorbance capacity (ORAC FL) assay. The hydrophilic (H)-ORAC FL of these foods ranged from 15 to 4202 μmole Trolox equivalents (TE)/100 g, and the lipophilic (L)-ORAC FL from 11 to 109 μmole TE/100 g. The L-ORAC FL of all the items analyzed contributed less than 5% of the total antioxidant capacity (TAC), except for sunflower oil (42%). Cultivar and seasonal availability influenced the H-ORAC FL of some, but not all, fruits. The Golden Delicious apple cultivar has a lower ( P < 0.05) H-ORAC FL (with peel and peeled) compared to the other apple cultivars analyzed. Household thermal processing decreased the H-ORAC FL of cabbage, brown onion and baby marrow (zucchini) ( P < 0.05) and the L-ORAC FL of potato and green beans ( P < 0.05). Although the H-ORAC FL of refined grains (e.g. maize porridge) is among the lowest, such foods make a substantial contribution to the daily dietary intake of the South African population.

Antioxidant capacity and hydrophilic phytochemicals in commercially grown native Australian fruits

Hydrophilic phytochemicals and antioxidant capacities of eight commercially grown native Australian fruits were determined. Kakadu plum ( Terminalia ferdinandiana) contained a 6-fold higher level of total phenolic compounds and quandong ( Santalum acuminatum) a 1.9-fold higher level of total phenolic compounds (TP, Folin–Ciocalteu assay) than blueberry ( Vaccinum sp., cv. Biloxi). Both fruits displayed superior oxygen radical-scavenging capacity (ORAC-H assay) that was, respectively 4.1-fold and 6.5-fold of that of blueberry. The total reducing capacity (TRC; ferric reducing antioxidant power (FRAP) assay) of Kakadu plum and quandong exceeded the TRC of blueberry, respectively, 13.1- and 2.3-times. The primary sources of antioxidant capacities in the evaluated fruits were phenolic acids (benzoic and cinnamic) and flavonoids (flavonols, flavanones and anthocyanins) tentatively detected by liquid chromatography–mass spectrometry (LC–PDA–MS/MS). A high level of vitamin C was recorded for Kakadu plum and Australian citrus fruits. The major organic acids detected were citric and malic acid.

Effect of High-Oxygen Atmospheres on the Antioxidant Potential of Fresh-Cut Tomatoes

The effect of different initial in-package O2 and CO2 concentrations (2.5 kPa of O2 + 5 kPa of CO2, 10 kPa of O2 + 5 kPa of CO2, and 21, 60, and 80 kPa of O2) on the antioxidant potential of fresh-cut tomatoes was investigated. Changes in individual phenolic compounds, individual carotenoids, vitamin C, and antioxidant capacity as well as in O2, CO2, and ethylene headspace concentrations inside packages were assessed for 21 days at 4 degrees C. High-oxygen and passive atmospheres induced higher production of carotenoids and phenolic compounds. The degradation of the initial content of vitamin C was highly promoted by the presence of oxygen. Lower hydrophilic antioxidant capacity (DPPH assay) was obtained in tomato slices stored under 80 kPa of O2, whereas the antioxidant capacity of the lipophilic fraction was enhanced with oxygen availability inside headspace packages. Therefore, 2.5 kPa of O2 + 5 kPa of CO2 atmospheres not only reduced the formation of carotenoids but also maintained vitamin C in fresh-cut tomatoes.

Roast effects on the hydrophilic and lipophilic antioxidant capacities of peanut flours, blanched peanut seed and peanut skins

Hydrophilic and lipophilic oxygen radical antioxidant capacity (H&L-ORAC) of peanut flours, blanched peanut seed, and peanut skins were characterised across a range of roast intensities. H-ORAC ranged from 5910 to 7990, 3040 to 3700 and 152,290 to 209,710 μmoles Trolox/100 g for the flours, seed, and skins, respectively. H-ORAC increased linearly with darker seed colour after roasting at 166 °C from 0 to 77 min, whereas skin H-ORAC peaked after roasting for 7 min. Linear correlations with H-ORAC and total phenolic content were observed. Additionally, completely defatted peanut seed were solubilised (5% w/w) in water and H-ORAC measured. For these samples, H-ORAC decreased with roast intensity which correlated with soluble protein. L-ORAC ranged from 620 to 1120, 150 to 730 and 2150 to 6320 μmoles Trolox/100 g for peanut flours, seed, and skins, respectively. L-ORAC increased linearly with both darker seed colour and skin colour across the 77 min range. L-ORACs of roasted peanuts and ingredients are discussed in terms of tocopherol contents and Maillard reaction products.

Serum antioxidant capacity in head and neck cancer patients receiving chemoradiation therapy.

Measurements of in vivo antioxidant capacity might help to resolve a controversy about the safety of antioxidant supplements during concurrent chemoradiation therapy for cancers of the head and neck. Some data suggest that antioxidant supplements chemoradiation therapy may reduce treatment toxicities; other evidence indicates they may protect tumor cells from oxidative damage. The study defined serum antioxidant capacity before, during and after outpatient therapy. Total, hydrophilic and lipophilic oxygen radical absorbance capacity was measured in serum using the ORACFL microplate method. The procedure is based on the inhibition of peroxyl radical‐ induced oxidation initiated by thermal decomposition of azo‐compounds using fluorescein as the fluorescent probe. The median age of the subjects (n=27) was 58. Forty four percent took supplements. Most were smokers and reported smoking during therapy. Quantifying antioxidant intakes was complicated by treatment toxicities. Total (P=0.0081) and hydrophilic (P=0.0222) antioxidant capacity declined significantly between the pretreatment and end of radiation visits; no changes were detected in the lipophilic fraction. There was, however, marked interindividual variability in the temporal patterns of the lipophilic fraction. To our knowledge, this is the first report of antioxidant capacity in cancer patients receiving similar treatments.

Influence of environment and genotype on polyphenol compounds and in vitro antioxidant capacity of native Andean potatoes ( Solanum tuberosum L.)

The influence of environment and genetics on total phenolic content and hydrophilic antioxidant capacity (H-ORAC) of potato tubers was evaluated using 13 native Andean genotypes. Cultivars were grown at two highland locations in Peru: Huancayo and Huancani. Environmental conditions significantly affected the total phenolic contents and H-ORAC values in a cultivar-dependent manner. However, the potato genotype was the most determining factor of the observed variations. The effects of environment on individual phenolic compounds were also significant in terms of quantity, whereas the chemical profile remained stable across environmental conditions. To gain an insight into the observed antioxidant capacity of potato extracts, the individual and combined antioxidant effects of the main potato phenolic compounds were investigated. The ORAC values of reconstituted polyphenol mixtures reflecting the authentic phenolic composition of potato extracts were higher than expected from the summing of the ORAC values of individual phenolic compounds, indicating synergistic effects. The authentic potato extracts showed either a higher or a lower ORAC value than their reconstituted counterparts, suggesting positive or negative interactions with other compounds. Taken together, our results lead us to the following conclusions: (i) the hydrophilic antioxidant capacity observed in potato extracts is the result of various and complex interactions that could be attributed to phenolic compounds, to other non-identified molecules, and to synergistic as well as antagonistic effects between all these components and (ii) the high stability of the ranking of cultivars across environment in terms of phenolic content and antioxidant capacity indicates that the native Andean cultivars could be confidently used within breeding programs aiming at improving the health-promoting value of potato.

Cooking does not decrease hydrophilic antioxidant capacity of wild blueberries

The present study examined the effects of domestic cooking methods on the hydrophilic antioxidant activity (HAA) of wild blueberries. Baked, microwaved, simmered, and pan-fried frozen wild blueberries, and a thawed uncooked control, were analyzed for HAA using an ABTS/H2O2/HRP decoloration method. All cooking treatments were derived from recipes using wild blueberries, and were performed in triplicate. A randomized block design was used to determine whether there were statistical differences in antioxidant content after cooking and between each of the trials. There were no statistically significant decreases after cooking the thawed berries. On both a fresh weight and a dry weight basis, pan-fried blueberries had significantly higher HAA than baked, simmered, and control blueberries (P<0.05). Antioxidants in wild blueberries appear to be heat stable since cooked berries retained significant HAA. Cooked wild blueberries can be recommended as a good source of dietary antioxidants.

Modification of the Health-Promoting Value of Potato Tubers Field Grown under Drought Stress: Emphasis on Dietary Antioxidant and Glycoalkaloid Contents in Five Native Andean Cultivars (Solanum tuberosum L.)

The effects of drought stress on dietary antioxidant and glycoalkaloid contents in potato tubers were investigated using a selection of five native Andean cultivars. Both freshly harvested and 4 month-stored tubers were analyzed. Responses to drought stress were highly cultivar-specific. The antioxidant contents of the yellow tuber-bearing cultivars (Sipancachi and SS-2613) were weakly affected by the drought treatment, whereas the pigmented cultivars demonstrated highly cultivar-dependent variations. A drastic reduction of anthocyanins and other polyphenols was revealed in the red- (Sullu) and purple-fleshed (Guincho Negra) cultivars, whereas an increase was shown in the purple-skinned and yellow-fleshed cultivar (Huata Colorada). The hydrophilic antioxidant capacity (evaluated by Folin-Ciocalteu and H-oxygen radical absorbance capacity assays) was highly correlated with the polyphenol content and followed, therefore, the same behavior upon drought. Carotenoid contents, including beta-carotene, as well as vitamin E, tended to increase or remain stable following drought exposure, except for the cultivar Sullu, in which the level of these lipophilic antioxidants was decreased. Vitamin C contents were not affected by drought with the exception of Guincho Negra, in which the level was increased. These variations of health-promoting compounds were associated with increased or stable levels of the toxic glycoalkaloids, alpha-solanine and alpha-chaconine. Storage at 10 degrees C for 4 months tended to decrease the concentrations of all dietary antioxidants, except those of vitamin E. This storage also reduced the drought-induced variations observed in freshly harvested tubers. These results were discussed in terms of their implications for human diet and health as well as in plant stress defense mechanisms.

Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors

Dietary consumption of anthocyanins, a class of pigments produced by higher plants, has been associated with protection against a broad range of human diseases. However, anthocyanin levels in the most commonly eaten fruits and vegetables may be inadequate to confer optimal benefits. When we expressed two transcription factors from snapdragon in tomato, the fruit of the plants accumulated anthocyanins at levels substantially higher than previously reported for efforts to engineer anthocyanin accumulation in tomato and at concentrations comparable to the anthocyanin levels found in blackberries and blueberries. Expression of the two transgenes enhanced the hydrophilic antioxidant capacity of tomato fruit threefold and resulted in fruit with intense purple coloration in both peel and flesh. In a pilot test, cancer-susceptible Trp53(-/-) mice fed a diet supplemented with the high-anthocyanin tomatoes showed a significant extension of life span.

Bovine lactoferrin supplementation supports immune and antioxidant status in healthy human males

Dietary supplements of bovine lactoferrin are purported in consumer literature to enhance and support the immune system response through their antioxidant, antibacterial, and antiviral properties. Our aim was to investigate more fully the potential immune modulating properties and antioxidant activity of an oral supplementation of bovine lactoferrin in humans. Using an intraindividual repeated measure design, 8 healthy males aged 30 to 55 years, self-administered daily for 21 days, one capsule of placebo for 7 days, followed by 100 mg of lactoferrin for 7 days, followed by 200 mg of lactoferrin for 7 days. Peripheral blood lymphocyte subset counts, T-cell activation, natural killer (NK) cell cytotoxicity, serum cytokine levels (tumor necrosis factor [TNF]-alpha, interferon [IFN]-gamma, interleukin [IL]-2, IL-4, IL-6, and IL-10), and serum hydrophilic, lipophilic, and total antioxidant capacity were repeatedly measured before and after each progressive supplementation. Statistically significant increases were found between presupplementation levels and levels after 200 mg of supplementation in total T-cell activation (as measure by CD3(+)) (P < .001), helper T-cell activation (as measure by CD4(+)) (P < .001), cytotoxic T-cell activation (as measured by CD8(+)) (P < .001), and hydrophilic antioxidant capacity (P < .05). No significant changes were seen in the other parameters measured. These results support the proposal that oral supplements of bovine lactoferrin may be a useful adjunct toward modulation of immune activity, in particular T-cell activation and antioxidant status.