Evaluation Of Total Antioxidant Capacity Research Articles

Flavonoids in Selected Mediterranean Fruits: Extraction, Electrochemical Detection and Total Antioxidant Capacity Evaluation

AbstractFlavonoids are natural phenolic derivatives that, in low concentration, can provide health benefits by preventing biomolecules (proteins, nucleic acids, lipids, sugars) oxidative damage through free radical mediated reactions. The flavonoids, in selected Mediterranean seasonal fruits: apricot, sour cherry, plum, pomegranate, date, prickly pear (cactus fruit), and nectarine, by RP‐HPLC, coupled with photodiode array and electrochemical detectors, after microwave‐ultrasound assisted extraction, using flavonoid standards, were detected. The total antioxidant capacity in the lyophilized fruit extracts, by differential pulse voltammetry, (electrochemical index‐EI), integrated peak area, and chronoamperometry, was evaluated. In the lyophilized fruit extracts, and the catechin standard, the free radical scavenger efficient concentration (EC50), using DPPH. assay, was determined.

Flavonoids electrochemical detection in fruit extracts and total antioxidant capacity evaluation

Phenolic compounds detection in fruit extracts from: açai, bacuri, buriti, blackberry, black mulberry, blueberry, juçara, physalis, raspberry, and tamarillo, have been performed by reverse-phase high performance liquid chromatography with electrochemical detection (RP-HPLC-EC), using two detectors in series: a wall-jet detector flow cell with a glassy carbon electrode, and a thin-layer flow cell detector with a boron doped diamond electrode. This methodology, in gradient elution mode, was successfully used to detect seventeen phenolic compounds in the fruit extracts. The total antioxidant capacity of the fruit extracts by the electrochemical quantitative index (EI) and the method of capture of diphenilpicrilhydrazil (DPPH●) free radical “efficient concentration” (EC50), was evaluated. A very good correlation between EI and EC50 assays has been obtained, the fruit with the highest total antioxidant capacity being blackberry, while physalis exhibited the lowest antioxidant power.

Free radical scavenger screening of total antioxidant capacity in herb and beverage using graphene/PEDOT: PSS-modified electrochemical sensor

This work describes the development of a novel nanocomposite- graphene/poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) modified screen-printed carbon electrode (G/PEDOT:PSS/SPCE) for the evaluation of total antioxidant capacity (TAC) based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Droplet-like nanostructures of G/PEDOT: PSS were fabricated on the SPCE surface via electrospraying. The electrochemical behaviors of both unmodified SPCE and G/PEDOT: PSS modified SPCE were investigated by cyclic voltammetry (CV) using a standard ferri/ferrocyanide [Fe(CN)6]3/4-. Interestingly, electrosprayed G/PEDOT: PSS can enhance the current response due to simple increase of the SPCE surface area. Compared to an unmodified SPCE, the peak potential difference (ΔEp) between anodic and cathodic peak potential of G/PEDOT: PSS modified SPCE substantially decreased, indicating the faster electron transfer kinetics. Moreover, our system can be used for quantitation of TAC by chronoamperometric detection of residual non-reacted DPPH level at the interference free cathodic region. With addition of standard Trolox antioxidant, the cathodic DPPH current decreased. The calibration curve of Trolox antioxidant was found in a range of 5–30μM with a limit of detection (S/N=3) of 0.59μM and a limit of quantification (S/N=10) of 1.97μM. Finally, this novel electrochemical sensor was successfully applied for TAC evaluation in Thai herb and herbal beverage. The results showed a good agreement with the conventional UV–visible spectrophotometric results.

DNA-based sensor against nitrite oxide radical: Evaluation of total antioxidant capacity in beverages

Reactive nitrogen and oxygen species are produced in cells and play an important role in the oxidative metabolism; when in abnormal concentrations, they are able to induce oxidative damage on biomolecules, namely in DNA. In this paper it is described, an electrochemical DNA-based sensor against NO radical developed for total antioxidant capacity (TAC) evaluation. The sensor consisted on dA20 (adenine-rich oligonucleotide) physically adsorbed into carbon paste electrode (CPE). When this dA20-CPE was damaged, by immersion in a freshly generated NO radical, a protective effect onto dA20 was observed in the presence of antioxidants (ascorbic, gallic, caffeic, p-coumaric acids). Electrochemical studies were performed through square wave voltammetry. The construction of the sensor is simple, fast and the results indicated that the DNA-based sensor is suitable, accurate, and can be used to the assessment of TAC in commercial samples of juices.

Evaluation of Total Antioxidant Capacity of Saliva in High School Students.

Background and Objective:Imbalance between oxidative stress and saliva antioxidants plays a major role in initiation and spread of dental caries. The aim of this study was to evaluate the total antioxidant capacity (TAC) of saliva in dental caries.Methods:In this case-control study which employed high school students (14-18 years), the un-stimulated saliva samples of 60 students without dental caries (control group) and 60 students with dental caries (with at least 5 teeth levels of dental caries) were gathered. Each group comprised of males (half of cases) and females (half of cases). TAC of saliva was measured by Zellbio® (Netherlands) in terms of micmol/L. The data were analyzed using the SPSS software (ver. 17.0) and t-test with considering significance level at 0.05.Results:TAC of saliva was significantly lower in cases with dental caries (0.256±0.106) compared to those without dental caries (0.396±0.077); P< 0.001. There was no statistically significant difference of TAC of saliva between males (0.319±0.119) and females (0.333±0.113) irrespective of dental caries (P=0.507).Conclusion:The results of the study indicated that there was a reverse association between dental caries and TAC of saliva.

Evaluation of Total Antioxidant Capacity (TAS) by Using Fuzzy Logic

Evaluation of Total Antioxidant Capacity (TAS) by Using Fuzzy Logic

Nutraceutical value of yellow- and red-fleshed South African plums (Prunus salicina Lindl.): evaluation of total antioxidant capacity and phenolic composition.

Ten South African plum cultivars and selections, including yellow- and red-fleshed plums from two harvest seasons were evaluated in terms of nutraceutical value (phenolic composition, total polyphenol content (TPC) and total antioxidant capacity (TAC)) and fruit attributes (colour, fruit mass, etc.). Plums were evaluated at two maturity stages, i.e., directly after harvest (unripe) and after a commercial cold storage and ripening regime (ripe). The phenolic composition of South African plums varied greatly, both qualitatively and quantitatively, between cultivars and selections. Neochlorogenic acid, cyanidin-3-O-glucoside and quercetin-3-O-glucoside were the predominant hydroxycinnamic acid, anthocyanin and flavonol, respectively, although not present in all plums. The flavan-3-ols, (+)-catechin, (−)-epicatechin and procyanidins B1 and B2, were present in all plums. Red-fleshed plums tended to display higher TAC and TPC than yellow-fleshed plums. The flavan-3-ol content was highly correlated with TAC. The effect of harvest season was cultivar-dependent, but cultivar differences were not obscured. In terms of maturity stage, the ripe fruits tended to contain higher levels of anthocyanins and some flavonol compounds, although the TPC and TAC were not affected in most cases. South African plums, especially the red-fleshed selections PR04-32 and PR04-35, were shown to provide generally high TAC and TPC compared to literature values.

Lab-on-valve combined with a kinetic-matching approach for fast evaluation of total antioxidant capacity in wines

The ABTS˙+ assay, based on reduction of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical cation, has been automated using flow injection based methods, but biased results are often obtained because the scavenging reaction is not complete upon detection, providing underestimated antioxidant values for samples containing slow reacting compounds. In this work a mesofluidic lab-on-valve (LOV) system was developed to provide fast determination of total antioxidant capacity in a miniaturized fashion. The sample volume was downscaled to 1 μl, with consumption of 97 μl of ABTS (6.8 nmol) per assay. Total antioxidant capacity values for red wines were attained in <1 min by application of the kinetic matching approach, using tannic acid as standard. Calibration curves were linear between 2.5 and 12.5 μM of tannic acid, with a determination throughput of 36 h−1. No statistical difference was found for Trolox equivalent antioxidant capacity (TEAC) values obtained using either an end-point batch-wise microplate method (reaction time of 300 min) or the proposed LOV method.

The protective effect of Aloysia triphylla aqueous extracts against brain lipid-peroxidation

In a normal diet, the use of herbs may contribute significantly to the total intake of plant antioxidants and even be a better source of dietary antioxidants than many other food groups. Therefore, the aims of this study were to evaluate the protective effect of aqueous extracts of Aloysia triphylla (infusion and decoction) against lipid-peroxidation of brain homogenates and to determine changes in the prooxidant/antioxidant balance when the plant material is added. In order to elucidate a possible antioxidant mechanism in vitro evaluation of total antioxidant capacity, oxygen species scavenging ability and reducing power (RP) were studied. Tested extracts had shown a strong inhibition of lipid-peroxidation measured as thiobarbituric acid-reactive products of lipid-peroxidation (TBARS) and chemiluminescence. Furthermore, infusion and decoction exhibited free radical trapping ability, expressed by the capacity to scavenge superoxide and hydrogen peroxide. Additionally, both aqueous extracts presented antioxidant activity measured as total reactive antioxidant potential (TRAP), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS) scavenging activity and RP. These results suggest that the lipid-peroxidation inhibition mechanism proposed is that the antioxidants present in Aloysia triphylla could act as strong scavengers of reactive oxygen species not only at the initiation of the lipid-peroxidation chain reaction, but also at the propagation step. Therefore, they could be used as prophylactic and therapeutic agents for those diseases where the occurrence of oxidative stress and lipid-peroxidation contributes to the progression of damage.

Polyphenolic content and antioxidant activity of leaf extracts from Quercus durifolia, Quercus eduardii, Quercus sideroxyla and Quercus resinosa

The phenolic content and antioxidant activities of extracts from Quercus durifolia, Quercus resinosa, Quercus eduardii and Quercus sideroxyla leaves were studied. Extracts were obtained by successive extraction with aqueous acetone (70%) followed by methanol (50%). Antioxidant activities were determined using a single electron transfer (SET) and hydrogen atom transfer (HAT) based assays. For SET-based the assays performed were, 2,2-diphenyl-1-picryl hydrazine (DPPH) inhibition expressed as IC50, redox potential, as mV, inhibition of the low density lipoprotein (LDL) oxidation, as % of inhibition. For HAT-based assay, crocin bleaching technique was applied; a kinetics approach was used for the evaluation of total antioxidant capacity and the results presented in terms of equivalence by weight of a reference antioxidant. Acetone extracts (PFQA) from leaves of all Quercus species showed the best antioxidant capacity. Q. resinosa (PFQr) exhibited the best antioxidant capacity among the Quercus species analyzed either in acetone or methanol extracts (PFQM). Distinctive results are: DPPH IC50, PFQrA = 78.3 µg/g, PFQrM = 250.7 µg/g; In Redox potential, PFQrA = 147.0 mV, PFQrM = 201.6 mV; In LDL oxidation inhibition: 98.2% and in inhibition of crocin bleaching, PFQrA = 1.08 g, PFQrM = 0.98 g. In conclusion, Quercusleaves might be used as potential source of polyphenolic antioxidants. Key words: Quercus sp., SET-based assay, HAT-based assay, phenolic compounds, antioxidant activity.

Direct measurement of total antioxidant capacity of cereals: QUENCHER-CUPRAC method

Polyphenols in cereal samples are distributed as free, soluble-esterified, and insoluble-bound forms either esterified or etherified to cell wall constituents. In the evaluation of total antioxidant capacity (TAC) of cereals, rather difficult and time-consuming acid, alkaline and enzymatic treatments of residue have been applied to complete the extraction of bound phenolic compounds. Thus, this work is aimed to measure the TAC of cereals (i.e. barley, wheat, rye, oat) by the ‘QUENCHER procedure’ (involving forced solubilization of bound phenolics by oxidizing TAC reagents) with the direct use of copper(II)–neocuproine (Cu(II)–Nc) reagent of the CUPric Reducing Antioxidant Capacity (CUPRAC) assay. In this novel ‘QUENCHER-CUPRAC’ method, reaction time and solvent composition parameters were optimized, and the method was applied to cereal samples with CUPRAC reagent dissolved in 1:1 (v/v) ethanol–water mixture. The antioxidant capacities of soluble and insoluble fractions were simultaneously measured to give a hierarchic TAC order of cereals as: barley>rye>oat>wheat. The TAC values of cereals measured by QUENCHER-CUPRAC were higher than those of original QUENCHER method using ABTS•+ and DPPH reagents. Polyphenolic mixtures in a cellulose matrix gave additive TAC values with QUENCHER-CUPRAC. The proposed method correlated linearly with QUENCHER-ABTS•+ (r=0.956) and QUENCHER-DPPH (r=0.976).

Evaluation of total antioxidant capacity of saliva and serum in caries-free and caries-active adults: An in-vivo study

Oxidative stress is defined as an imbalance between the production of reactive oxygen species and antioxidant defense systems which are widely recognized as an important feature of many diseases including dental caries, suggesting that total antioxidant status may be of importance in determining the progression of caries. The aim of this study was to estimate the total antioxidant capacity (TAC) in saliva and serum of caries-free and caries-active adults and to correlate the TAC level with DMFT index (D = decayed, M = missing, F = filled, T = teeth). The present study included 100 healthy adults who were divided into four groups: Control, group I, group II, and group III, with a DMFT index 0, <3, <10, and >10, respectively. Saliva and serum samples were collected from all the four groups. The TAC of saliva and serum was estimated by phosphomolybdenum method. One-way analysis of variance (ANOVA) was used to compare the TAC of saliva and serum. Only differences with "P" < 0.05 were considered statistically significant. The mean TAC level of both saliva and serum increased significantly (P < 0.001) with the DMFT index. Total antioxidant capacity of saliva has a linear relation with caries, i.e., as the severity of caries increases, the TAC level also increases.

Evaluation of total antioxidant capacity of saliva in type 2 diabetic patients with and without periodontal disease: A case-control study

Background:Diabetes mellitus (DM) has been linked with oxidative stress and decreased antioxidant defense. A connection has been established between diabetes and periodontal disease.Aim:The aim of present study was to compare salivary total antioxidant capacity of type 2 DM patients and healthy subjects with and without periodontal disease.Materials and Methods:A total of 120 subjects consisting of 30 type 2 DM patients with periodontal disease; 30 type 2 DM patients without periodontal disease; 30 healthy subjects with periodontal disease; 30 healthy subjects without periodontal disease were included in the study. After clinical measurement and samplings, total antioxidant capacity in saliva of type 2 diabetic and healthy subjects were determined, and the data were tested by non-parametric tests. Total antioxidant capacity of the clinical samples was determined spectrophotometrically.Results:The mean salivary total antioxidant capacity was lowest in diabetic patients with periodontitis.Conclusion:Total antioxidant capacity is inversely proportional to the severity of inflammation and can be used as an useful marker of periodontitis in healthy and diabetic patients.

An estimation and evaluation of total antioxidant capacity of saliva in children with severe early childhood caries

BACKGROUND. The available evidence implicating the involvement of oxidative stress in the caries process suggests that local antioxidant status may be of importance in determining the susceptibility to the caries process. AIM. The aim of this study was to estimate the total antioxidant capacity (TAC) in unstimulated saliva of healthy children with and without severe early childhood caries (S-ECC) and to correlate the individual TAC level with dmft (d = decayed, m = missing, f = filled, t = teeth) score and age. MATERIAL AND METHODS. The TAC of saliva was investigated in 100 healthy children in the age range of 3-5 years divided in two groups, control and study group based on the absence or presence of caries, respectively. The antioxidant capacity of saliva was estimated by an adaptation of ABTS [2, 2'-Azino-di-(3-ethylbenzthiazoline sulphonate)] assay. RESULTS. The mean TAC level in the saliva of the children in study group was found to be significantly increased (P < 0.001), and a significantly linear regression was seen between the TAC and dmft score (P < 0.001) whereas it was insignificant between the TAC and age (P = 0.078). CONCLUSION. The results indicated that TAC of saliva increased significantly in children with S-ECC and increasing prevalence of dental caries predisposes to the increase in TAC of saliva.

Sequential injection analysis with electrochemical detection as a tool for economic and rapid evaluation of total antioxidant capacity

This work presents a new flow-based coupled electrochemical technique for evaluation of “total antioxidant capacity (TAC)”. A sequential injection (SI) with amperometric detection was applied to the TAC analysis of commercial instant ginger infusion beverages using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. Besides having chromogenic properties, the ABTS reagent behaves as an electroactive species at the glassy carbon electrode in phosphate buffer pH 7.0, the decrease of the cathodic current signal of the ABTS+ radical after reaction with antioxidants can be monitored. The SI system, furnished with an in-house electrochemical detection cell (ECD), was optimized with respect to the applied potential, sample and reagent volume, and flow rate to the detector. Gallic acid was used as the standard antioxidant and the capacity was reported as gallic acid equivalent (GAE) unit. TAC measurements of ginger infusions at the optimum condition were performed using the proposed technique and also with the classical batch spectrophotometric ABTS assay. TAC values obtained from our method and the standard method are in good agreement (r2=0.956). The SI-amperometric technique provided satisfactory precision (4.11% RSD) with rapid sample throughput (40samplesh−1). Also using this method, the consumption of the expensive ABTS reagent was greatly reduced.

Electrochemical DNA-sensor for evaluation of total antioxidant capacity of flavours and flavoured waters using superoxide radical damage

In this paper, a biosensor based on a glassy carbon electrode (GCE) was used for the evaluation of the total antioxidant capacity (TAC) of flavours and flavoured waters. This biosensor was constructed by immobilising purine bases, guanine and adenine, on a GCE. Square wave voltammetry (SWV) was selected for the development of this methodology. Damage caused by the reactive oxygen species (ROS), superoxide radical (O 2· −), generated by the xanthine/xanthine oxidase (XOD) system on the DNA-biosensor was evaluated. DNA-biosensor encountered with oxidative lesion when it was in contact with the O 2· −. There was less oxidative damage when reactive antioxidants were added. The antioxidants used in this work were ascorbic acid, gallic acid, caffeic acid, coumaric acid and resveratrol. These antioxidants are capable of scavenging the superoxide radical and therefore protect the purine bases immobilized on the GCE surface. The results demonstrated that the DNA-based biosensor is suitable for the rapid assess of TAC in beverages.

The correlations between oxidative stress markers and indoor volatile organic compounds among the general population in Ansan and Incheon cities, Korea

Indoor VOC and aldehydes may increase oxidative stress for home dwellers. Our study aim was to determine the correlations between oxidative stress markers in subjects and exposure to VOC and aldehydes in homes. Among ninety five control subjects in Ansan and Incheon (South Korea), blood samples were collected for evaluation of total antioxidant capacity, malondialdehyde (MDA) in plasma, protein carbonyl, and DNA damage of lymphocytes. Indoor VOC and aldehydes were measured in the homes of the subjects. A partial correlation analysis was performed to assess the association between oxidative stress markers and VOC/aldehydes with adjustment for formaldehyde levels. There were significant correlations between the total antioxidant capacity and some chemicals, including heptanes, α-pinene, β-pinene, and decanal in the young age (10–19 years) group. The many correlations between VOC/aldehydes and DNA damage expressed as the Olive tail moment showed statistically significant in the middle (20–39 years) and older age (40–59 years) groups, but not in the young age group. These correlation could not account for the exposure to specific chemicals being related to an increase in DNA damage because most VOC/aldehydes were highly correlate exac other except some chemicals. In conclusion, we found that DNA damage of T- and B-lymphocytes evaluated by the Comet assay could be sensitive oxidative stress markers to evaluate the human response to VOC/ aldehydes exposure in middle and older age groups. Our study also showed that age affected the association between VOC/aldehydes exposure and oxidative stress markers including DNA damage and antioxidants. However, further studies are needed to confirm these correlations in a larger number of subjects because of limitations of this study, including a lack of personal exposure.

Cigarette smoke effect on total salivary antioxidant capacity, salivary glutathione peroxidase and gamma‐glutamyltransferase activity

Saliva is the first biological fluid that inhaled cigarette smoke (CS) encounters. CS contains several carcinogens known to initiate and promote tumourigenesis and metastasis. One of the aims of this study was to establish if glutathione peroxidase and gamma-glutamyltranspherase (GGT) could be used as possible markers for evaluating the oral oxidative stress caused by smoking. The effect of CS on free radical generation was investigated using two methods. Using different assays, different antioxidants present in saliva may be evidenced due to the different principles on which they are based. Our results indicate that exposure to CS caused a statistically significant decrease of both salivary glutathione peroxidase (p < 0.01) and salivary GGT (p < 0.01). We also found that exposure to CS caused a statistically significant decrease of salivary total antioxidant status (p < 0.01). Such decreases may have a consistent role in the mechanisms by which the toxic effects of CS initiate oral inflammatory diseases, promote precancerous transformations, and destroy the oral cavity homeostasis. Therefore the evaluation of total antioxidant capacity of saliva is important but it must be done together with the evaluation of salivary specific markers of oxidative stress, such as uric acid, albumin and possibly, GGT.

Quality, Nutritional Value and Therapeutical Properties of Foods: Highlights in Fruit Research

Fruits possess different antioxidant properties depending on their content in antioxidants. The consumer is aware of the importance of looking for diets containing a large array of compounds that may help the organisms in the daily struggle against chronic diseases. If fruit intake is not sufficient to support the RDA for several micronutrients, an interesting help can be that of foods naturally enriched with antioxidants. The evaluation of Total Antioxidant Capacity of fruits is of pivotal importance in assessing the nutritional attributes of fruits and other horticultural products. By means of specific breeding programs it is possible to select antioxidant enriched fruit varieties. These features are susceptible to be improved through generations in order to release fruits with enhanced nutritional features. The availability of high quality and nutritionally enriched fruit at competitive costs may be a useful tool in the planning of healthy diets.

Update on fruit antioxidant capacity: a key tool for Mediterranean diet

To review and update the most relevant research dealing with the antioxidant properties of fruits which can be useful in Mediterranean and other healthy diets. Personal perspectives and late data. International. The evaluation of total antioxidant capacity of fruits is of pivotal importance in assessing the nutritional attributes of these products. By means of specific breeding programmes, it is possible to select antioxidant-enriched fruit varieties. These features are susceptible to be improved through generations in order to release fruits with enhanced nutritional features. The availability of high quality and nutritionally enriched fruit at competitive costs may be a useful tool in the planning of healthy diets.