Changes in bioactive compounds and antioxidant activity of three Amaranthus L. genotypes from a model to household processing

Amaranthus L. leaves are consumed as vegetables and are a rich source of secondary plant metabolites. The phenolic profiles of the three analyzed genotypes by LC-Q-TOF-MS/MS and HPLC-DAD were characterized by high amounts of hydroxycinnamic glucaric and -isocitric acids. 'Gartenfuchsschwanz' (A. hybridus L.) and 'Red Callaloo' (A. tricolor L.) had similar profiles. 'Gemüse-Amaranth' (A. tricolor L.) had a high amount of caffeoylglucaric acid 4, which was isolated, and afterward identified by NMR. Its antioxidant activity, measured by TEAC, DPPH, and TPC, was similar to 5-caffeoylquinic acid, common in many plant species. The antioxidant activity of Amaranthus L. can be explained rather by their different phenolic- and ascorbic acid concentrations than by their species. Household cooking reduces antioxidant activity due to oxidation processes while leaching into cooking water could be neglected. Amaranthus L. baked into a wheat-dough-matrix showed lower phenolic concentrations, presumably due to the formation of phenol-protein-bounds and thermal degradation.

Chemoinformatic modelling of the antioxidant activity of phenolic compounds

BACKGROUND

Antioxidants are chemicals used to protect foods from deterioration by neutralizing free radicals and inhibiting the oxidative process. One approach to investigate the antioxidant activity is to develop quantitative structure-activity relationships (QSARs).

RESULTS

A curated database of 165 structurally heterogeneous phenolic compounds with the Trolox equivalent antioxidant capacity (TEAC) was developed. Molecular geometries were optimized by means of the GFN2-xTB semiempirical method and diverse molecular descriptors were obtained afterwards. For model development, V-WSP unsupervised variable reduction was used before performing the genetic algorithms-variable subset selection (GAs-VSS) to construct the best five-descriptor multiple linear regression model. The coefficient of determination and the root mean square error were used to measure the performance in calibration (R²  = 0.789 and RMSEC = 0.381), and test set prediction (Q²  = 0.748 and RMSEP = 0.416), along several cross-validation criteria. To thoroughly understand the TEAC prediction, a fully explained mechanism of action of the descriptors is provided. In addition, the applicability domain of the model defined a theoretical chemical space for reliable predictions of new phenolic compounds.

CONCLUSION

This in silico model conforms to the five principles stated by the Organisation for Economic Co-operation and Development. The model might be useful for virtual screening of the antioxidant chemical space and for identifying the most potent molecules related to an experimental measurement of TEAC activity. In addition, the model could assist chemists working on computer-aided drug design for the synthesis of new targets with improved activity and potential uses in food science. © 2023 Society of Chemical Industry.

LC-MS- and 1H NMR-Based Metabolomics to Highlight the Impact of Extraction Solvents on Chemical Profile and Antioxidant Activity of Daikon Sprouts (Raphanus sativus L.)

Currently, the interest of consumers towards functional foods as source of bioactive compounds is increasing. The sprouts of Raphanus sativus var longipinnatus (Brassicaceae) are "microgreens" popular, especially in gourmet cuisine, for their appealing aspect and piquant flavour. They represent a functional food due to their high nutritional value and health-promoting effects. Herein, the sprouts of daikon were extracted by different solvent mixtures to highlight how this process can affect the chemical profile and the antioxidant activity. An in-depth investigation based on a preliminary LC-ESI/LTQOrbitrap/MS profiling was carried out, leading to the identification of nineteen compounds, including glucosinolates and hydroxycinnamic acid derivatives. An undescribed compound, 1-O-feruloyl-2-O-sinapoyl-β-D-glucopyranoside, was isolated, and its structure was elucidated by NMR spectroscopy. The phenolic content and radical scavenging activity (DPPH and TEAC assays), along with the ability to activate Nrf2 (Nrf2-mediated luciferase reporter gene assay) of polar extracts, were evaluated. The results showed the highest antioxidant activity for the 70% EtOH/H2O extract with a TEAC value of 1.95 mM and IC50 = 93.97 µg/mL in the DPPH assay. Some 50% and 70% EtOH/H2O extracts showed a pronounced concentration-dependent induction of Nrf2 activity. The extracts of daikon sprouts were submitted to 1H NMR experiments and then analyzed by untargeted and targeted approaches of multivariate data analysis to highlight differences related to extraction solvents.

Chemical Composition, Antioxidant Properties, and Antibacterial Activity of Essential Oils of Satureja macrostema (Moc. and Sessé ex Benth.) Briq

Satureja macrostema is a plant that is located in various regions of Mexico and is used in a traditional way against illness. Essential oils (EOs) were obtained from leaves Satureja macrostema and the chemical composition was evaluated by gas chromatography-mass spectrometry (GC-MS). The antioxidant effect of the oil was assayed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and by Trolox Equivalent Antioxidant Capacity (TEAC). In vitro antibacterial activity against Escherichia coli and Staphylococcus aureus was determined using a broth microdilution assay and thin layer chromatography-direct bioautography (TLC-DB) to identify active antibacterial compounds. The EOs analysis showed 21 compounds, 99% terpenes, and 96% oxygenated monoterpenes, with trans-piperitone epoxide (46%), cis-piperitone epoxide (22%), and piperitenone oxide (11%) as more abundant compounds. Likewise, S. macrostema EOs showed an antioxidant activity of DPPH = 82%, with 50% free radical scavenging (IC₅₀) = 7 mg/mL and TEAC = 0.005, an antibacterial effect against E. coli of 73% inhibition, and 81% over S. aureus at dose of 100 µL of undiluted crude oil. The TLC-DB assay showed that the most active compounds were derived from piperitone. The comparison with other studies on S. macrostema shows variability in the compounds and their abundances, which can be attributed to climatic factors and the maturity of plants with similar antioxidant and antibacterial activities.

Effect of Instant Controlled Pressure Drop (DIC) on Polyphenols, Flavonoids and Antioxidant Capacity of Green Lentils (Lens culinaris)

Instant controlled pressure drop (DIC) is one of the emerging technologies in food processing; it can be used for drying, freezing and the extraction of bioactive molecules without damaging their properties. Legumes, such as lentils, are one of the most consumed foods in the world; however, they are mainly cooked by boiling, which causes the loss of antioxidant compounds. This work evaluated the effect of 13 different DIC treatments (with pressure ranges of 0.1-0.7 MPa and times of 30-240 s) on the content of polyphenols (Folin-Ciocalteu and High Performance Liquid Chromatography HPLC) and flavonoids (2-aminoethyl diphenylborinate) as well as the antioxidant activity (DPPH and TEAC) of green lentils. The DIC 11 treatment (0.1 MPa, 135 s) obtained the best release of polyphenols, which in turn are related to antioxidant capacity. The abiotic stress generated by DIC could lead to the breakdown of the cell wall structure, which favors the availability of antioxidant compounds. Finally, the most efficient conditions for DIC to promote the release of phenolic compounds and maintain antioxidant capacity were found under low pressures (<0.1 MPa) and short times (<160 s).

Polymer Encapsulated Liposomes for Oral Co-Delivery of Curcumin and Hydroxytyrosol

Curcumin (Cur) is a hydrophobic polyphenol from the rhizome of Curcuma spp., while hydroxytyrosol (HT) is a water-soluble polyphenol from Olea europaea. Both show outstanding antioxidant properties but suffer from scarce bioavailability and low stability in biological fluids. In this work, the co-encapsulation of Cur and HT into liposomes was realized, and the liposomal formulation was improved using polymers to increase their survival in the gastrointestinal tract. Liposomes with different compositions were formulated: Type 1, composed of phospholipids and cholesterol; Type 2, also with a PEG coating; and Type 3 providing an additional shell of Eudragit^® S100, a gastro-resistant polymer. Samples were characterized in terms of size, morphology, ζ-potential, encapsulation efficiency, and loading capacity. All samples were subjected to a simulated in vitro digestion and their stability was investigated. The Eudragit^®S100 coating demonstrated prevention of early releases of HT in the mouth and gastric phases, while the PEG shell reduced bile salts and pancreatin effects during the intestinal digestion. In vitro antioxidant activity showed a cumulative effect for Cur and HT loaded in vesicles. Finally, liposomes with HT concentrations up to 40 μM and Cur up to 4.7 μM, alone or in combination, did not show cytotoxicity against Caco-2 cells.

Hybrid Classification/Regression Approach to QSAR Modeling of Stoichiometric Antiradical Capacity Assays' Endpoints

Quantitative structure-activity relationships (QSAR) are a widely used methodology allowing not only a better understanding of the mechanisms of chemical reactions, including radical scavenging, but also to predict the relevant properties of chemical compounds without their synthesis, isolation and experimental testing. Unlike the QSAR modeling of the kinetic antioxidant assays, modeling of the assays with stoichiometric endpoints depends strongly on the number of hydroxyl groups in the antioxidant molecule, as well as on some integral molecular descriptors characterizing the proportion of OH-groups able to enter and complete the radical scavenging reaction. In this work, we tested the feasibility of a "hybrid" classification/regression approach, consisting of explicit classification of individual OH-groups as involved in radical scavenging reactions, and using further the number of these OH-groups as a descriptor in simple-regression QSAR models of antiradical capacity assays with stoichiometric endpoints. A simple threshold classification based on the sum of trolox-equivalent antiradical capacity values was used, selecting OH-groups with specific radical stability- and reactivity-related electronic parameters or their combination as "active" or "inactive". We showed that this classification/regression modeling approach provides a substantial improvement of the simple-regression QSAR models over those built on the number of total phenolic OH-groups only, and yields a statistical performance similar to that of the best reported multiple-regression QSARs for antiradical capacity assays with stoichiometric endpoints.

Quantification of Total Phenols and Antioxidants in Coffee Samples of Different Origins and Evaluation of the Effect of Degree of Roasting on Their Levels

Phenolic and antioxidant compounds have received considerable attention due to their beneficial effects on human health. The aim of this study is to determine the content of total phenols and antioxidants in fifty-two coffee samples of different origins, purchased from the Jordanian local market, and investigate the effect of the degree of roasting on the levels of these compounds. The coffee samples were extracted using the hot water extraction method, while Folin−Ciocalteu (FC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay methods were used to analyze these compounds. The results showed that the highest content of total phenol (16.55 mg/g equivalent to GAE) was found in the medium roasted coffee, and the highest content of antioxidants (1.07 mg/g equivalent to TEAC) content was found in the green coffee. Only light and medium roasted coffee showed a significant correlation (p < 0.05, R2 > 0.95) between the average of total phenolic and antioxidant content. A negative correlation between the antioxidant content and the degree of roasting (p < 0.05, R2 > 0.95) were shown, while it did not correlate with phenolic contents. Previously, a positive correlation between antioxidant and chlorogenic acids content was observed, with no correlation between the origin of coffee samples nor heavy metal content, which was previously determined for the same coffee samples. These findings suggest that the antioxidant content for coffee extracts is largely determined by its chlorogenic acid content, rather than the coffee origin or total phenolic and heavy metals content.

Impact of Cultivar Selection and Thermal Processing by Air Drying, Air Frying, and Deep Frying on the Carotenoid Content and Stability and Antioxidant Capacity in Carrots (Daucus carota L.)

Epidemiological data suggest that consuming diets rich in carotenoids can reduce the risk of developing several non-communicable diseases. Thus, we investigated the extent to which carotenoid contents of foods can be increased by the choice of food matrices with naturally high carotenoid contents and thermal processing methods that maintain their stability. For this purpose, carotenoids of 15 carrot (Daucus carota L.) cultivars of different colors were assessed with UHPLC-DAD-ToF-MS. Additionally, the processing effects of air drying, air frying, and deep frying on carotenoid stability were applied. Cultivar selection accounted for up to 12.9-fold differences in total carotenoid content in differently colored carrots and a 2.2-fold difference between orange carrot cultivars. Air frying for 18 and 25 min and deep frying for 10 min led to a significant decrease in total carotenoid contents. TEAC assay of lipophilic extracts showed a correlation between carotenoid content and antioxidant capacity in untreated carrots.

Gallic Acid Mitigates 5-Hydroxymethylfurfural Formation while Enhancing or Preserving Browning and Antioxidant Activity Development in Glucose/Arginine and Sucrose/Arginine Maillard Model Systems

The current trend of lowering 5-hydroxymethylfurfural (5-HMF) dietary exposure is challenging since its formation is parallel with the development of food color, flavor and aroma. We aimed to investigate the effect of gallic acid (GA) addition on 5-HMF formation, color development and antioxidant activity (AA) in a series of Maillard Reaction (MR) model systems. The effects of GA addition on browning and AA development were not uniform for all model systems, but always occurred in the same direction, indicating that these phenomena were interconnected. GA mitigated 5-HMF development in four of the nine tested systems, possibly by preventing the oxidation of MR intermediates. Correlation analysis indicated that when GA addition mitigated 5-HMF formation, browning was either promoted or not affected. The proposed strategy was effective for glucose/arginine and sucrose/arginine systems, since GA mitigated 5-HMF formation (49% and 54%, respectively) in addition to increasing color development and antioxidant activity.

Verification of the Conditions for Determination of Antioxidant Activity by ABTS and DPPH Assays-A Practical Approach

The ABTS and DPPH methods are among the most popular assays of antioxidant activity determination. Attempts to adapt them to different analytes and the search for the highest values of antioxidant activity has resulted in a large variety of assay conditions to be presented in the literature, including the way the measurement is made. This makes it difficult to relate the results to real oxidation systems, and often makes it impossible to compare them. Such a comparison is limited in advance by the use of stable radicals that do not exist in nature and that react differently from those generated in food or in vivo. Therefore, it is important to introduce measures aimed at standardizing the conditions of the activity assay, including reaction time and several reaction environments suitable for testing different groups of compounds. In this study, we used natural antioxidants of various structures: phenolic acids, flavonoids, peptides and corresponding amino acids, ascorbic acid and α-tocopherol, and also synthetic analogues of selected compounds. The curves of dependence of the measured absorbance on the concentration of antioxidants were described, the ranges of linearity were determined, and the value of the error made when reading in various ranges of dependencies was estimated. We also determined and compared the activity values using two popular methods (IC₅₀ and TEAC), taking into account different environments and reaction times. Based on the collected data, recommendations were formulated regarding the reaction conditions adapted to the studies of individual groups of antioxidants, and unified reaction times were proposed. Taking into account the state before reaching the equilibrium of antioxidants reacting in a complex manner, this approach may introduce a simplified reference to the competing reaction that occurs in reality.

Antioxidant activities of major tryptophyllin L peptides: A joint investigation of Gaussian-based 3D-QSAR and radical scavenging experiments

The red tree frog Litoria rubella from Australia has been studied for several decades showing that their dorsal skin glands secrete a number of small peptides containing a Pro-Trp sequence, known as tryptophyllin L peptides. Although peptides from many genera of Australian frogs have been reported to possess a variety of biological activities, the bioactivities of this peptide family have remained to be discovered. In this study, we investigated the antioxidant potency of a number of tryptophyllin L peptides for the first time using a joint statistical and experimental approach in which predictions based on Gaussian three-dimensional quantitative structure-activity relationship (3D-QSAR) models were employed to guide an in vitro experimental investigation. Two tryptophyllin tripeptides P-W-L (OH) and P-W-L (NH₂ ) were predicted to have the Trolox equivalent antioxidant capacity (TEAC) values of 0.80 and 0.87 μM Trolox/μM peptide, respectively. With those promising results, antioxidant capabilities of five tryptophyllin L peptides with the common core Pro-Trp-Leu were synthesized and subjected to 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing ability of plasma (FRAP) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS˙⁺ ) radical scavenging assays. The tests indicated that all the tested tryptophyllin L peptides, noticeably S-P-W-L (OH) and F-P-W-L (NH₂ ), are strong ABTS˙⁺ radical scavengers and moderate scavengers in the other two assays. The results, thus, suggested that the tryptophyllin L peptides are likely to be a part of the skin antioxidant system helping the frog to cope with drastic change in oxygen exposure and humidity, as they inhabit over a large area of Australia with a wide climate variation.

Effects of Production Region, Production Systems and Grape Type/Variety on Nutritional Quality Parameters of Table Grapes; Results from a UK Retail Survey

Grapes contain high concentrations of secondary metabolites and antioxidants that have been linked to a reduction of several chronic diseases. Here, we report results of a UK retail survey, which investigated the effect of the production region (Mediterranean vs. South Africa), grape type (white vs. red vs. black) and variety, and production system (organic vs. conventional) on antioxidant activity and concentrations of phenolic compounds in table grapes. Black grapes had ~180% total antioxidant activity (TAA), ~60% higher total phenolic content (TPC) and ~40 times higher anthocyanin concentrations (TAC) than white grapes, while red grapes had intermediate levels of TAA, TPC and TAC. The effects of season and production system and differences between varieties of the same grape type were substantially smaller. Grapes imported from Mediterranean countries in summer had a 14% higher TPC and ~20% higher TAA than grapes imported from South Africa in winter, and organic grapes had a 16% higher TPC and 22% higher TAA, but ~30% lower TAC than conventional grapes. Significant differences in TPC, TAA and/or TAC between organic and conventional grapes could only be detected for specific grape types, varieties and/or sampling years.

A simple one-pot determination of both total phenolic content and antioxidant activity of honey by polymer chemosensors

We have developed a new method for the rapid (2 h) and inexpensive (materials cost < 0.02 €/sample) "2-in-1" determination of the total phenolic content (TPC) and the antioxidant activity (AOX) in honey samples. The method is based on hydrophilic colorimetric films with diazonium groups, which react with phenols rendering highly colored azo groups. The TPC of the sample is correlated to its trolox equivalent antioxidant capacity (TEAC). The intensity of the color allows us to determine both TPC and TEAC of the sample by the analysis of a picture taken with a smartphone that is analysed by the use of the color-definition-parameters (RGB). The controlled light conditions and the systematic use of the same camera avoid the periodical calibration of the system improving the efficiency of the method. Thus, it is a simple method carried out by non-specialized personnel and it involves much lower money and time investment compared to traditional methods.

Influence of a Selenium Biofortification on Antioxidant Properties and Phenolic Compounds of Apples (Malus domestica)

Biofortified apples seem to be a suitable produce. In this study, different selenium forms and application levels were applied to the two apple varieties ‘Golden Delicious’ and ‘Jonagold’, grown in the years 2017 and 2018 in order to increase the selenium uptake within a typical Western diet. It was shown that the biofortification, which was performed as a foliar application implemented in usual calcium fertilization, led to significantly increased selenium contents in the fruits. Furthermore, biofortification affected the total phenolic content (TPC), the polyphenol oxidase activity (PPO), as well as the antioxidant activity (AOA), the latter measured with the two well-known assays Trolox Equivalent Antioxidant Capacity Assay (TEAC) and Oxygen Radical Absorbance Capacity Assays (ORAC). The varying selenium forms and application levels showed a differing influence on the parameters mentioned before. Higher fertilizer levels resulted in higher selenium accumulation. It was found that PPO activity fluctuates less in biofortified apples. With regard to TPC, selenate led to higher amounts when compared to the untreated controls and selenite resulted in lower TPC. AOA analysis showed no clear tendencies as a result of the selenium biofortification. In the case of ‘Jonagold’, a higher AOA was generally measured when being biofortified, whereas, in the case of ‘Golden Delicious’, only one form of application led to higher AOA. Additionally, differences in the amount of major phenolic compounds, measured with High Performance Liquid Chromatography Mass Spectrometry (HPLC-DAD-ESI-MSⁿ), were observed, depending on the conditions of the biofortification and the variety.

ABTS/PP Decolorization Assay of Antioxidant Capacity Reaction Pathways

The 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^•+) radical cation-based assays are among the most abundant antioxidant capacity assays, together with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-based assays according to the Scopus citation rates. The main objective of this review was to elucidate the reaction pathways that underlie the ABTS/potassium persulfate decolorization assay of antioxidant capacity. Comparative analysis of the literature data showed that there are two principal reaction pathways. Some antioxidants, at least of phenolic nature, can form coupling adducts with ABTS^•+, whereas others can undergo oxidation without coupling, thus the coupling is a specific reaction for certain antioxidants. These coupling adducts can undergo further oxidative degradation, leading to hydrazindyilidene-like and/or imine-like adducts with 3-ethyl-2-oxo-1,3-benzothiazoline-6-sulfonate and 3-ethyl-2-imino-1,3-benzothiazoline-6-sulfonate as marker compounds, respectively. The extent to which the coupling reaction contributes to the total antioxidant capacity, as well as the specificity and relevance of oxidation products, requires further in-depth elucidation. Undoubtedly, there are questions as to the overall application of this assay and this review adds to them, as specific reactions such as coupling might bias a comparison between antioxidants. Nevertheless, ABTS-based assays can still be recommended with certain reservations, particularly for tracking changes in the same antioxidant system during storage and processing.

Quantitative analysis of the relationship between structure and antioxidant activity of tripeptides

Peptides from enzymatic hydrolysates of food proteins exhibit significant antioxidant activity. Several studies have attempted to determine the factors contributing to the antioxidant activity of peptides; however, the physicochemical properties and factors essential for the antioxidant activity of peptides are still unclear. In this study, in order to clarify the factors important for peptide antioxidant activity based on the properties of component amino acids, 55 tripeptides were synthesized from 20 natural amino acids and their antioxidant activity was measured using the Trolox equivalent antioxidant capacity (TEAC) assay system. The tripeptides were divided into two data sets: a training set comprising 50 compounds and a validated set comprising five compounds. The structure-activity relationship of the training set was then analyzed using classical quantitative structure-activity relationship (QSAR) analysis. The study findings demonstrate that the presence of a cysteine residue at any position, an aromatic amino acid at the C-terminus, higher hydrophobicity of the N-terminal residue, and smaller HOMO-LUMO energy gap of the middle residue can significantly enhance the antioxidant activity. The activities of the five validated compounds were predicted using the constructed QSAR model, and a good correlation between measured and predicted activities was observed. The information obtained from the QSAR model could be useful for effective production of antioxidant peptides from food proteins such as egg white proteins.

Comparison of Oxidative Status of Human Milk, Human Milk Fortifiers and Preterm Infant Formulas

Preterm and low birth weight infants require specific nutrition to overcome the accumulated growth deficit, and to prevent morbidities related to postnatal growth failure. In order to guarantee an adequate nutrient-intake, mother’s own milk, when available, or donor human milk, are usually fortified with additional nutrients, in particular proteins. Fortification with processed ingredients may result in additional intake in oxidative compounds, deriving from extensive heat treatments, that are applied during processing. The aim of the present work was to compare the in vitro antioxidant activity and oxidative compound content conveyed by different preterm infant foods and fortifiers, namely raw and pasteurized human milk, two different preterm infant formulas, three bovine milk-based fortifiers and two experimental donkey milk-based fortifiers. Univariate and multivariate statistical analyses revealed significant differences between the different products. The use of human milk minimizes the intake of dietary oxidative compound in comparison to infant formulas, irrespective of pasteurization or fortification, especially as far as malondialdehyde content is concerned. The addition of fortifiers to human milk increases its antioxidant capacity, and the choice of the protein source (hydrolysed vs. whole proteins) differently impacted the resulting total antioxidant capacity of the diet.

Dietary Total Antioxidant Capacity and Risk of Gastrointestinal Cancers: A Systematic Review and Meta-analysis of Observational Studies

BACKGROUND

Gastrointestinal (GI) cancers are common types of cancers. Among different factors that affect the etiology of GI cancers, diet has an important contribution. Dietary antioxidants decrease oxidative stress which plays a pivotal role in carcinogenesis. Several studies assessed the relation between dietary total antioxidant capacity (TAC) and risk of GI cancers. Dietary TAC was measured by three indices including FRAP (ferric ion reducing antioxidant power), TRAP (total radical-trapping antioxidant parameter), and TEAC (trolox equivalent antioxidant capacity). We performed a systematic review and meta-analysis of published studies to determine the association between dietary TAC and GI cancers risk.

METHODS

Eligible studies were selected from PubMed, ISI Web of Science and Scopus databases from inception until May 2018. Case-control and cohort studies that reported GI cancer risk estimates for dietary TAC were included. We ignored the distinction between case-control and cohort studies. We applied random-effects to estimate pooled relative risks. Subgroup analysis was done based on study design.

RESULTS

Among the seven observational studies that were included, four were cohort studies and three were case-control studies. Dietary FRAP, TRAP, and TEAC reduced GI cancer risk: FRAP; 0.71; 95% CI: 0.58-0.85, TRAP; 0.65; 95% CI: 0.57-0.75, TEAC; 0.70; 95% CI: 0.59-0.83, respectively.

CONCLUSION

This study indicated that dietary TAC significantly decreased the risk of GI cancers. Nevertheless, further prospective studies are required to clarify the association between dietary TAC and risk of GI cancers.

Assessment of Antioxidant Capacity and Putative Healthy Effects of Natural Plant Products Using Soybean Lipoxygenase-Based Methods. An Overview

In the last decades, increasing demand of antioxidant-rich foods and growing interest in their putative role in prevention of degenerative diseases have promoted development of methods for measuring Antioxidant Capacity (AC). Nevertheless, most of these assays use radicals and experimental conditions far from the physiological ones, and are able to estimate only one or a few antioxidant mechanisms. On the other hand, the novel LOX/RNO and LOX⁻FL methods, based on secondary reactions between the soybean lipoxygenase (LOX)-1 isoenzyme and either 4-nitroso-N,N-dimethylaniline (RNO) or fluorescein (FL), may provide a more comprehensive AC evaluation. In fact, they are able to detect simultaneously many antioxidant functions (scavenging of some physiological radical species, iron ion reducing and chelating activities, inhibition of the pro-oxidant apoenzyme) and to highlight synergism among phytochemicals. They are applied to dissect antioxidant properties of several natural plant products: food-grade antioxidants, cereal and pseudocereal grains, grain-derived products, fruits. Recently, LOX⁻FL has been used for ex vivo AC measurements of human blood samples after short- and long-term intakes of some of these foods, and the effectiveness in improving serum antioxidant status was evaluated using the novel Antioxidant/Oxidant Balance (AOB) parameter, calculated as an AC/Peroxide Level ratio. An overview of data is presented.

The structure-antioxidant activity relationship of dehydrodiferulates

In this study, 11 dehydrodiferulic acids (DFAs) and 8 diethyl dehydrodiferulates (DEFs) were synthesized and evaluated by Trolox equivalent antioxidant capacity (TEAC) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) assays for their antioxidant properties to understand the Structure-Antioxidant Activity Relationship (SAR) of these dehydrodiferulates. In both assays, the order of antioxidant activity for all tested ferulic acid dimers were consistent except for 3-(4-Hydroxy-3-methoxy-benzylidene)-5-(4-hydroxy-3-methoxy-phenyl)-3H-furan-2-one (2, 8-8-lactone DC DFA, not occurred naturally) being the best antioxidant by TEAC test. The order of antioxidant activity of diferulic acid ethyl esters, evaluated by both assays, was not consistent; however, TEAC and DPPH assays provided consistent results for certain set of ethyl diferulates. In this study most of dimeric ferulates, with three exceptions, showed higher radical-scavenging efficacy than the monomers. Comparing the antioxidant activities of the tested diferulates suggested that the phenolic hydroxyl group, electron donating methoxyl group, and stable conjugated transient structures dictate the antioxidant activity of diferulates.

Encapsulation of Curcumin-Loaded Liposomes for Colonic Drug Delivery in a pH-Responsive Polymer Cluster Using a pH-Driven and Organic Solvent-Free Process

The present study aimed to develop and optimize liposome formulation for the colonic delivery of biologically active compounds. A strategy to facilitate such targeting is to formulate liposomes with a polymer coating sensitive to the pH shifts in the gastrointestinal tract. To this end, liposomes encapsulating curcumin-chosen as the biologically active compound model-and coated with the pH-responsive polymer Eudragit S100 were prepared and characterized. Curcumin was encapsulated into small unilamellar vesicles (SUVs) by the micelle-to-vesicle transition method (MVT) in a simple and organic solvent-free way. Curcumin-loaded liposomes were coated with Eudragit S100 by a fast and easily scalable pH-driven method. The prepared liposomes were evaluated for size, surface morphology, entrapment efficiency, stability, in vitro drug release, and curcumin antioxidant activity. In particular, curcumin-loaded liposomes displayed size lower than 100 nm, encapsulation efficiency of 98%, high stability at both 4 °C and 25 °C, high in vitro antioxidant activity, and a cumulative release that was completed within 200 min. A good Eudragit S100 coating which did not alter the properties of the curcumin-loaded liposomes was obtained. The present work therefore provides a fast and solvent-free method to prepare pH-responsive polymer-coated liposomes for the colonic delivery of biologically active compounds.

Polyphenolic Compounds Analysis of Old and New Apple Cultivars and Contribution of Polyphenolic Profile to the In Vitro Antioxidant Capacity

Polyphenols are antioxidant ingredients in apples and are related to human health because of their free radical scavenging activities. The polyphenolic profiles of old and new apple cultivars (n = 15) were analysed using high-performance liquid chromatography (HPLC) with diode array detection (DAD). The in vitro antioxidant capacity was determined by total phenolic content (TPC) assay, hydrophilic trolox equivalent antioxidant capacity (H-TEAC) assay and hydrophilic oxygen radical absorbance (H-ORAC) assay. Twenty polyphenolic compounds were identified in all investigated apples by HPLC analysis. Quercetin glycosides (203 ± 108 mg/100 g) were the main polyphenols in the peel and phenolic acids (10 ± 5 mg/100 g) in the flesh. The calculated relative contribution of single compounds indicated flavonols (peel) and vitamin C (flesh) as the major contributors to the antioxidant capacity, in all cultivars investigated. The polyphenolic content (HPLC data) of the flesh differed significantly between old (29 ± 7 mg/100 g) and new (13 ± 4 mg/100 g) cultivars, and the antioxidant capacity of old apple cultivars was up to 30% stronger compared to new ones.

On-Line Screening, Isolation and Identification of Antioxidant Compounds of Helianthemum ruficomum

Many Helianthemum species (Cistaceae) are recognized for their various medicinal virtues. Helianthemum ruficomum is an endemic species to the septentrional Sahara on which no report is available so far. The purpose of this work was to investigate the chemical composition and the radical scavenging capacity of this species and its isolated components. Collected from Mougheul (south-west of Algeria), the aerial parts were macerated with 80% EtOH/H₂O, after evaporation, the remaining extract was diluted with H₂O and extracted with petroleum ether, chloroform, ethyl acetate and n-butanol. EtOAc and n-BuOH extracts were evaluated for their free radical scavenging capacity by on-line HPLC-ABTS^•+ assay. The obtained data which were confirmed by TEAC and ORAC assays, allowed guiding the fractionation of these extracts by CC, TLC and reverse phase HPLC. Among the components, 14 were isolated and identified by spectroscopic analyses: protocatechuic acid (1), trans-tiliroside (2), cis-tiliroside (3), astragalin (4), picein (7), vanillic acid 4-O-β-d-glucopyranoside (8), lavandoside (9), 4-hydroxybenzoic acid 4-O-β-d-glucopyranoside (10), nicotiflorin (11), rutin (12), vicenin-2 (13), narcissin (14) and stigmasterol (5) and β-sitosterol (6) as a mixture (71% and 29%, respectively). Compounds 5, 7, 8, 9, 10 and 14 were new for the genus Helianthemum. The antioxidant power of all the isolated compounds was also evaluated by HPLC-ABTS^•+, TEAC and ORAC assays. The results clearly indicated high antioxidant potential of the extracts and tested compounds of this species especially, compounds 1, 4, 8, 9, 10 and 12.

Bioactive components of Prunus avium L. black gold (red cherry) and Prunus avium L. stark gold (white cherry) juices, wines and vinegars

Cherries are one of the most popular fruits, characterized by attractive colour, firmness, appearance and delicious tastes. Cherries are consumed fresh as well as in jams, wine, dried, candy and other processed products. Cherries vary in antioxidant properties and phenolic substances. The aim of the study was to determine the effects of ethanol and acetic acid fermentation on total antioxidant activities and phenolic substances of cherry juice. Total investigation of solids, pH, soluble solids, phenolic substances, ORAC and TEAC of Prunus avium L. cherry juices, macerated cherries wine, and vinegars were analyzed. All samples had 300.1-854.79 mg GAE/L of total phenolic contents, and 6.62-17.97 µmol/mL of ORAC values, and 1.5-5.5 mmol/mL of TEAC. Chlorogenic acid was present in the highest amount P. avium L. black gold vinegar.

Examination of secondary metabolites and antioxidant capacity of Anthyllis vulneraria, Fuchsia sp., Galium mollugo and Veronica beccabunga

Anthyllis vulneraria L., Fuchsia sp., Galium mollugo L., and Veronica beccabunga L. were selected to analyse the phenolic content and the antioxidant activity by ferric ion reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. The highest polyphenol, tannin, and flavonoid contents were measured in Fuchsia species (7.40 ± 0.8, 5.62 ± 0.7 and 0.72 ± 0.1 g/100 g dry weight), while the lowest values were detected in Anthyllis vulneraria (0.68 ± 0.02, 0.17 ± 0.03 and 0.45 ± 0.01 g/100 g dry weight) and Galium mollugo (1.77 ± 0.05, 0.49 ± 0.04 and 0.16 ± 0.06 g/100 g dry weight). The leaf extract of Fuchsia sp. had the highest, while the herb of A. vulneraria had the lowest antioxidant effect measured by both methods, which is probably related to total polyphenol, tannin, and flavonoid contents.

Different effectiveness of two pastas supplemented with either lipophilic or hydrophilic/phenolic antioxidants in affecting serum as evaluated by the novel Antioxidant/Oxidant Balance approach

Effectiveness in improving serum antioxidant status of two functional pastas was evaluated by the novel Antioxidant/Oxidant Balance (AOB) parameter, calculated as Antioxidant Capacity (AC)/Peroxide Level ratio, assessed here for the first time. In particular, Bran Oleoresin (BO) and Bran Water (BW) pastas, enriched respectively with either lipophilic (tocochromanols, carotenoids) or hydrophilic/phenolic antioxidants extracted from durum wheat bran, were studied. Notably, BO pasta was able to improve significantly (+65%) serum AOB during four hours after intake similarly to Lisosan G, a wheat antioxidant-rich dietary supplement. Contrarily, BW pasta had oxidative effect on serum so as conventional pasta and glucose, thus suggesting greater effectiveness of lipophilic than hydrophilic/phenolic antioxidants under our experimental conditions. Interestingly, no clear differences between the two pastas were observed, when AC measurements of either serum after pasta intake or pasta extracts by in vitro assays were considered, thus strengthening effectiveness and reliability of AOB approach.

Kinetics of ABTS derived radical cation scavenging by bucillamine, cysteine, and glutathione. Catalytic effect of Cu(2+) ions

Kinetics of reduction of the stable radical cation derived from 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) in reaction with the anti-rheumatic drug bucillamine (BUC) and two reference thiols - cysteine (Cys) and glutathione (GSH) was followed spectrophotometrically in acidic medium with 10-fold molar excess of the reductant. Decay of the radical is governed by pseudo-first order kinetics with small deviation in the case of GSH. H(+) ions displayed second order inhibition of the reaction with all the studied compounds. The reaction of BUC exhibits zero order kinetics to the radical at lower acidities with a moderate acceleration of the reaction rate by H(+) ions. A significant catalytic effect of Cu(2+) ions on the reactions with all the reductants was observed. The most sensitive to Cu(2+)-catalysis was the reaction of BUC with the radical cation, while Cu(2+) ions showed much lower effect on the reaction with GSH. The presence of EDTA strongly inhibited the reactions and equalized the reaction rates for all the reductants. A Cu(I) selective chelator bathocuproine disulfonate reduced the reaction rate with Cys, but accelerated the reaction with BUC at the lower acidities. The experimental results were rationalized in the framework of the mechanism of reductive chelation. The conclusions may have important consequences for interpretation of antioxidant capacity assays, such as TEAC, utilizing the ABTS derived radical cation.

Relationship between antioxidant status and oxidative stability in lamb meat reinforced with dietary rosemary diterpenes

The relationship between the antioxidant status of fresh meat and oxidative stability of chilled-packed meat obtained from lambs fed on a diet supplemented with two different doses of a rosemary extract containing carnosic acid and carnosol was studied. The incorporation of rosemary extract in the lamb diet led to the deposition of functional levels of the diterpenic metabolite C19H22O3 in meat, which improved its stability against oxidation. The antioxidant status could be assessed through both the radical scavenging capacity (DPPH and TEAC) and the ferric reducing antioxidant power (FRAP). In general, antioxidant status values correlated better (P < 0.05) with the changes in CIELAB colour, malondialdehyde and sensory scoring than with the changes in hexanal and protein carboxylation measured in the lamb cuts kept under protective atmosphere for up to 14 days. The FRAP and DPPH assays were more suitable than the TEAC assay for predicting meat oxidation and any resulting discolouration and rancidity.

[Behavior of antioxidant parameters in young cattle during the course of the year]

OBJECTIVE

To analyze the behavior of antioxidant parameters in young cattle over 1 year and to detect possible health-related deficits during certain periods.

MATERIALS AND METHODS

Every 2 months over the course of 1 year, six healthy 12-month-old Holstein Friesian/German black and white heifers underwent a clinical examination and blood samples were obtained. The 36 animals were kept in tie-stalls during September, November, January, March and July, and solely at pasture in May. The antioxidant parameters superoxide dismutase (SOD), glutathione peroxidase (GPX) and the Trolox equivalent antioxidant capacity (TEAC), hematocrit and the metabolic parameters β-hydroxybutyrate, bilirubin, cholesterol, protein, albumin, urea, haptoglobin, calcium, inorganic phosphate, iron, alkaline phosphatase, aspartate transaminase, glutamate dehydrogenase and creatine kinase were determined.

RESULTS

The GPX activities in September and January were significantly lower than those from March till July. The TEAC concentrations were in particular lower in January and significantly lower in March than in September and November. Differing SOD activities were not statistically significant. The correlation between SOD and GPX during the entire period was significant as well as between SOD and TEAC throughout the year except in January, whereas GPX and the TEAC only significantly correlated in November and from March till July. Albumin significantly correlated with the TEAC. The metabolic parameters were within the physiological range at all times, except urea in November and July and phosphate in May.

CONCLUSION

The young cattle showed significantly reduced GPX activities from September to January, and reduced TEAC concentrations particularly in January and March. Decreased GPX activity is indicative of a low selenium supply. Among other disadvantages, this is unfavorable for the development of heifers. A reduced provision with antioxidant agents, particularly vitamin E and β-carotene, is indicated by the TEAC and has negative effects that are comparable to those caused by a lack of selenium. In terms of health prophylaxis, particularly during winter, specific attention should be given to the supply of sufficient trace elements and good quality silage.

Stability and quality of herb (Pueraria Tuberosa)-milk model system

The medicinal benefits of herbs could be conveyed via certain foods as carriers. Milk is one of the important carrier which has been effectively used to deliver phytochemicals presents in herbs (mainly polyphenols) for targeted health benefits in the traditional Indian system of medical science. The present study was conducted to evaluate the effect of herb components (Pueraria tuberosa) on properties of Pueraria tuberosa-milk model system. The herb was added into cow milk on the basis of sensory evaluation (0.4 %) by using 9-point hedonic scale. The physical and chemical changes were evaluated after various processing treatments viz. pasteurization (72 °C, 15 s), sterilization (121 °C, 15 min), separation etc. These changes were determined using viscosity, hydroxy methyl furfural (HMF) value, ethanol stability, colour characteristics and trolox equivalent antioxidant capacity (TEAC). It was observed that addition of Pueraria tuberosa to milk resulted in decreased HMF content, ethanol stability and lightness whereas antioxidant activity, redness and yellowness increased as compared to control. It can be concluded that addition of Pueraria tuberosa to milk at 0.4 % concentration altered the functional properties of milk and Pueraira tuberosa could be suitable for preparation of low heat treated functional dairy food products.

Evaluation of antioxidant capacity of Chinese five-spice ingredients

Phenolic compounds in spices were reportedly found to possess high antioxidant capacities (AOCs), which may prevent or reduce risk of human diseases such as cardiovascular disease, cancer and diabetes. The potential AOC of Chinese five-spice powder (consist of Szechuan pepper, fennel seed, cinnamon, star anise and clove) with varying proportion of individual spice ingredients was investigated through four standard methods. Our results suggest that clove is the major contributor to the AOC of the five-spice powder whereas the other four ingredients contribute to the flavour. For example, the total phenolic content as well as ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) values increased linearly with the clove percentage in five-spice powder. This observation opens the door to use clove in other spice mixtures to increase their AOC and flavour. Moreover, linear relationships were also observed between AOC and the total phenolic content of the 32 tested spice samples.

[Age-related changes in antioxidant parameters in healthy calves between the first day of life and the 18th month taking into consideration selected metabolic parameters]

OBJECTIVE

To follow the age-dependent development of anti-oxidative metabolic parameters in healthy cattle from birth until 18 months of age.

MATERIAL AND METHODS

Blood samples from healthy female cattle were collected at days 1 and 7 post natum (p. n.) and during the 1st, 3rd, 6th, 9th, 12th and 18th month p. n. The antioxidant parameters superoxide dismutase (SOD), glutathione peroxidase (GPX) and Trolox equivalent antioxidative capacity (TEAC), haematocrit (Hct) and the metabolic parameters total protein, albumin, bilirubin, calcium, inorganic phosphate, iron, urea, cholesterol, β-hydroxybutyrate, alkaline phosphatase, aspartate transaminase, glutamate dehydrogenase, creatine kinase and haptoglobin were determined.

RESULTS

All three antioxidant parameters displayed a comparable time-course, with a maximum at 6 months p. n. With the exception of the 9th month p. n., significantly positive correlations were found constantly. GPX activity increased continuously from 50-80 U/ml Hct on day 1 p. n. to 100-190 U/ml Hct in the 6th month p. n. The significantly lowest activities were found on the 1st and 7th day p. n. SOD activity at the 1st (4500-5600 U/g haemoglobin [Hb]) and 7th day p. n. were significantly lower than in the 1st and 3rd month p. n. Activi- ties at 12 and 18 months displayed significantly lower values com- pared to the 1st, 3rd and 6th (5000-9100 U/g Hb) month p. n. The increase in the TEAC concentration from 220-290 µmol/l on day 1 to 260-340 µmol/l in the 6th month p. n. was non-significant. Thereafter, a significant decrease in the concentrations (p>0.05) was found.

CONCLUSION

Parallel trends for SOD, GPX and TEAC found in this study indicate a fully functioning antioxidant defence system in the calf, which is well adjusted to and able to compensate the inevitable oxidative stress of birth, onset of respiration, haemoglobin remodelling, forestomach development and other physiological processes.

Influence of the leaf content and herbal particle size on the presence and extractability of quantitated phenolic compounds in Cistus incanus herbal teas

A variety of Cistus incanus products and thereof a majority of herbal teas are offered by manufacturers despite a classification as Novel Food. For a re-evaluation of this legal status, a characterization of bioactive ingredients will provide data. These teas consist of various compositions of plant parts and particle sizes. Whereas some include high leaf contents with a small particle size, others mainly consist of woody stem parts. For the consumer it is of interest which product yields the highest concentrations of bioactive phenolic compounds in the final infusions. In this study, four commercially available samples were divided into leaves and stems. Additionally, one sample was reconstituted in three mixtures of these plant parts. The amount of wood was determined by cellulose concentration. The aim was to estimate the influence of the plant parts on the concentration of phenolic compounds, which were identified by LC-DAD-ESI-MS/MS and quantitated by LC-DAD. Furthermore, one herbal tea was separated into six fractions with different particle sizes to investigate the influence of particle size on the extractability of phenolic compounds. On basis of the results, the highest concentrations of bioactive compounds in the infusions were yielded when leafy parts with a small particle size were used for brewing.

RSM based optimized enzyme-assisted extraction of antioxidant phenolics from underutilized watermelon (Citrullus lanatus Thunb.) rind

Enzyme assisted solvent extraction (EASE) of phenolic compounds from watermelon (C. lanatus) rind (WMR) was optimized using Response Surface Methodology (RSM) with Rotatable Central Composite Design (RCCD). Four variables each at five levels i.e. enzyme concentration (EC) 0.5-6.5 %, pH 6-9, temperature (T) 25-75 °C and treatment time (t) 30-90 min, were augmented to get optimal yield of polyphenols with maximum retained antioxidant potential. The polyphenol extracts obtained under optimum conditions were evaluated for their in-vitro antioxidant activities and characterized for individual phenolic profile by RP-HPLC-DAD. The results obtained indicated that optimized EASE enhanced the liberation of antioxidant phenolics up to 3 folds on fresh weight basis (FW) as compared to conventional solvent extraction (CSE), with substantial level of total phenolics (173.70 mg GAE/g FW), TEAC 279.96 mg TE/g FW and DPPH radical scavenging ability (IC50) 112.27 mg/mL. Chlorogenic acid (115.60-1611.04), Vanillic acid (26.13-2317.01) and Sinapic acid (113.01-241.12 μg/g) were major phenolic acid found in EASEx of WMR. Overall, it was concluded that EASE might be efficient and green technique to revalorize under-utilized WMR into potent antioxidant phenolic for their further application in food and nutraceutical industries.

Antioxidant activity, total phenolic and flavonoid contents of some medicinal and aromatic plants used as herbal teas and condiments in Iran

Total phenolic and flavonoid contents and antioxidant activity of four Iranian herbs (Lamiaceae) were investigated. The antioxidant activity of methanol extracts of thyme (Thymus daenensis Celak.), Bakhtiari savory (Satureja bachtiarica Bung.), dragonhead (Dracocephalum multicaule Montbr & Auch), and woundwort (Stachys lavandulifolia Vahl.) was evaluated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP), and trolox equivalent antioxidant capacity (TEAC). A comparison of all plant extracts in the DPPH assay indicated that dragonhead and thyme were the most effective free radical scavenging agents. Thyme demonstrated a relatively strong antioxidant activity in both the FRAP and TEAC assays. The total phenolic content of all the extracts ranged from 99 to 208 mg TAE/g extract with thyme exhibiting the highest phenolic content. The flavonoid content of the extracts, which ranged from 10.1 to 22.2 rutin equivalents/g of extract, was highest in dragonhead. A positive correlation was noted between the total phenolic content and antioxidant activity in both the FRAP and TEAC assays, while no significant correlation was observed between the DPPH, TEAC, and FRAP assay and total flavonoid, suggesting that the level of antioxidant activity in these plants varies greatly, but the total phenolic in the plant extracts provided a substantial antioxidant activity. Experimental results indicate that thyme and dragonhead extracts could be an important dietary source of phenolic compounds with high antioxidant capacity.

Estimating the yin-yang nature of Western herbs: a potential tool based on antioxidation-oxidation theory

BACKGROUND

One of the biggest obstacles to progress in traditional Chinese medicine (TCM) development in Western countries is the difficulty of applying the traditional concepts to the Western medicinal plants, which are not traditionally described in ancient literature. During recent years, new advances in the field of understanding Yin/Yang aspects from a modern bioscientific point of view have led to the conclusion that antioxidationoxidation concepts might mirror a Yin-Yang relationship.

METHODS

This study was intended to integrate the Yin-Yang theory of the traditional Chinese medicine with modern antioxidation-oxidation theory, and to propose a biochemical tool based on redox parameters (e.g. antioxidant capacity, chemiluminescence-CL signal inducing capacity), usable for the classification of Western medicinal plants from Yin/Yang perspective. Trolox equivalent antioxidant capacity (TEAC) of six vegetal aqueous extracts (Symphitum officinalae (radix)-SYM, Inula helenium (radix)-INU, Calendula officinalis (flores)-CAL, Angelica arhanghelica (folium)ANG(F), Angelica arhanghelica (radix)-ANG(R), Ecbalium Elaterium (fruits)-ECB) and luminol-enhanced chemiluminescence of PMNL on addition of these vegetal extracts were measured. Percentages from the maximal or minimal values obtained were calculated for each extract (TEAC%, PMNL stimulation%, PMNL inhibition%, relative speed of action% (RSA%%)), specific Yin-Yang significance was assigned to each relative parameter. In the end, an integration of all the relative values was done, in order to find a global "Yin" or a "Yang" trait of each vegetal extract.

RESULTS

TEAC decreased in the following order: SYM > INU > CAL >ANG(F) > ANG(R > ECB. Three vegetal extracts (SYM > INU > ECB) decreased the luminol-enhanced chemiluminescence of PMNL, two (ANG(R) > ANG(F)) increased it, while one (CAL) had a dual effect. After the integration of the percentages, CAL was found to have a global "Yang" trait, while the rest of the plants had a global "Yin" trait.

CONCLUSIONS

TEAC% and PMNL inhibition% appears to correlate with the Yin properties of herbs, while PMNL stimulation% and RSA% might correlate with Yang aspects within the formal TCM classification system, and may be useful criteria in describing the Western herbs from a TCM point of view.

Differential induction of antioxidant stilbenoids in hairy roots of Vitis rotundifolia treated with methyl jasmonate and hydrogen peroxide

Stilbenoids are polyphenolic phytoalexins that exhibit potential health applications in humans. Hairy root cultures of muscadine grape (Vitis rotundifolia Michx.) were used to study the biochemical and molecular regulation of stilbenoid biosynthesis upon treatment with 100 μM methyl jasmonate (MeJA) or 10 mM hydrogen peroxide (H2O2) over a 96-h period. Resveratrol, piceid, and ε-viniferin were identified in higher concentrations in the tissue whereas resveratrol was the most abundant stilbenoid in the medium under either treatment. An earlier increase in resveratrol accumulation was observed for the MeJA-treated group showing a maximum at 12 h in the tissue and 18 h in the medium. Furthermore, the antioxidant capacity of extracts from the tissue and medium was determined by the 2,2'-azinobis[3-ethylbenzthiazoline sulfonic acid] (ABTS) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays showing correlation with the stilbenoid content. Fourteen candidate reference genes for qPCR were tested under the described experimental conditions and resulted in the selection of 5 reference genes. Quantitative analyses of transcripts for phenylalanine ammonia-lyase (PAL), resveratrol synthase (RS), and two stilbene synthases (STS and STS2) showed the highest RNA level induction at 3 h for both treatments with a higher induction for the MeJA treatment. In contrast, the flavonoid-related chalcone synthase (CHS) transcripts showed induction and a decrease in expression for MeJA and H2O2 treatments, respectively. The observed responses could be related to an oxidative burst triggered by the exposure to abiotic stressor compounds with signaling function such as MeJA and H2O2 which have been previously related to the synthesis of secondary metabolites.

Influence of βS allele in the lipid peroxidation and antioxidant capacity parameters

INTRODUCTION

The oxidative process plays a fundamental role in the pathophysiology of sickle cell anemia (SCA), and population and environmental characteristics may influence redox balance. The aim of this study was to evaluate lipid peroxidation and antioxidant capacity in Brazilian Hb S carriers undergoing different therapies.

METHODS

Blood samples from 270 individuals were analyzed (Hb SS, n = 68; Hb AS, n = 53, and Hb AA, n = 149). Hemoglobin genotypes were assessed through cytological, electrophoretic, chromatographic, and molecular methods. Plasma lipid peroxidation and antioxidant capacity were measured by spectrophotometric methods.

RESULTS

Patients with SCA who used iron-chelating drugs combined with hydroxyurea, associated with regular transfusions, showed lower levels of TBARS (P ≤ 0.05), higher levels of TEAC (P ≤ 0.01), and lower TBARS/TEAC ratio (R = 255.8). The redox profile of Hb AS subjects was not statistically different (P > 0.05) from that of Hb AA subjects.

CONCLUSION

The data suggest that oxidative stress is lower in the patients with SCA who received regular blood transfusions associated with the combined use of HU and iron chelators than the group received only HU. The redox system of the Hb AS carriers is compatible with the control group.

Extraction, chemical characterization and biological activity determination of broccoli health promoting compounds

Broccoli (Brassica oleracea L. var. Italica) contains substantial amount of health-promoting compounds such as vitamins, glucosinolates, phenolic compounds, and dietary essential minerals; thus, it benefits health beyond providing just basic nutrition, and consumption of broccoli has been increasing over the years. This review gives an overview on the extraction and separation techniques, as well as the biological activity of some of the above mentioned compounds which have been published in the period January 2008 to January 2013. The work has been distributed according to the different families of health promoting compounds discussing the extraction procedures and the analytical techniques employed for their characterization. Finally, information about the different biological activities of these compounds has been also provided.

In vitro measurements and interpretation of total antioxidant capacity

BACKGROUND

One of the strategies most commonly used to assess a free radical-antioxidant balance in chemical and biological systems is the determination of the total antioxidant capacity (TAC). A large amount of research has been published using TAC. However, it remains unclear which is the significance of these investigations for understanding the biological importance of free radical reactions.

SCOPE OF REVIEW

This review discusses the relevance and limitations of TAC for the assessment of the antioxidant activities present in food and food derivatives, and in body tissues and fluids.

MAJOR CONCLUSIONS

TAC determinations are simple, inexpensive, and able to evaluate the capacity of known and unknown antioxidants and their additive, synergistic and/or antagonistic actions, in chemical and biological systems. However, different TAC assays correlate poorly with each other, since each TAC assay is sensitive to a particular combination of compounds, but exclude many others. The TAC values for foods cannot be translated to the in vivo (human) antioxidant defenses, and furthermore, to health effects provided by that food.

GENERAL SIGNIFICANCE

Up to date, conclusions that can be drawn from the extensive amount of research done using TAC of foods or populations should not be considered when used for making decisions affecting population health. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.

Antioxidant Properties of Seeds from Lines of Artichoke, Cultivated Cardoon and Wild Cardoon

The artichoke (Cynara cardunculus L. subsp. scolymus L.), the cultivated cardoon (Cynara cardunculus var. altilis DC.) and the wild cardoon (Cynara cardunculus var. sylvestris L.) are species widely distributed in the Mediterranean area. The aim of this research was to evaluate the antioxidant properties of seeds from lines of artichoke and cultivated and wild cardoon in both aqueous-organic extracts and their residues by FRAP (Ferric Reducing Antioxidant Power) and TEAC (Trolox Equivalent Antioxidant Capacity) evaluations. Both artichoke and cardoon seeds are a good source of antioxidants. Among artichoke seeds, hydrolysable polyphenols contribution to antioxidant properties ranged from 41% to 78% for FRAP values and from 17% to 37% for TEAC values. No difference between cultivated and wild cardoon in antioxidant properties are reported. Our results could provide information about the potential industrial use and application of artichoke and/or cardoon seeds.

Metabolic profile and biological activities of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco: studies on the essential oil and polar extracts

We investigated the metabolic profile and biological activities of the essential oil and polar extracts of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco collected in south Portugal. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that oxygen-containing monoterpenes was the principal group of compounds identified in the essential oil. Camphor (40.6%) and fenchone (38.0%) were found as the major constituents. High-performance liquid chromatography with diode array detection (HPLC-DAD) analysis allowed the identification of hydroxycinnamic acids (3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids) and flavones (luteolin and apigenin) in the polar extracts, with rosmarinic acid being the main compound in most of them. The bioactive compounds from L. pedunculata polar extracts were the most efficient free-radical scavengers, Fe(2+) chelators and inhibitors of malondialdehyde production, while the essential oil was the most active against acetylcholinesterase. Our results reveal that the subspecies of L. pedunculata studied is a potential source of active metabolites with a positive effect on human health.

Chemical constituents with free-radical-scavenging activities from the stem of Fissistigma polyanthum

BACKGROUND

Fissistigma polyanthum is a liane belonging to the Annonaceae family and it is one of the most important crude drugs in traditional Chinese medicine.

OBJECTIVE

The objective was to describe the structural elucidation and the free-radical-scavenging activities of the isolated compounds from Fissistigma polyanthum.

MATERIAL AND METHODS

The chemical constituents were isolated and purified by normal, reverse column chromatography and HPLC. Their structures were identified by spectroscopic methods ((1)H NMR and (13)C NMR) and by comparison with literature values, and the free-radical-scavenging activities of these two compounds were also evaluated through three in vitro model systems (DPPH, trolox equivalent antioxidant capacity (TEAC) and Co (II) EDTA-induced luminol chemiluminescence by flow injection).

RESULTS

Two known compounds, named kanakugiol (1) and teutenone A (2), were isolated from the stem of Fissistigma polyanthum for the first time, and compound 1 exhibited moderate free-radical-scavenging activity.

CONCLUSION

Fissistigma polyanthum, which has traditionally been used as an important Chinese medicine, showed a certain free-radical-scavenging activity.

Advances in the analytical methods for determining the antioxidant properties of honey: a review

Free radicals and reactive oxygen species (ROS) have been implicated in contributing to the processes of aging and disease. In an effort to combat free radical activity, scientists are studying the effects of increasing individuals' antioxidant levels through diet and dietary supplements. Honey appears to act as an antioxidant in more ways than one. In the body, honey can mop up free radicals and contribute to better health. Various antioxidant activity methods have been used to measure and compare the antioxidant activity of honey. In recent years, DPPH (Diphenyl-1-picrylhydrazyl), FRAP (Ferric Reducing Antioxidant Power), ORAC (The Oxygen Radical Absorbance Capacity), ABTS [2, 2-azinobis (3ehtylbenzothiazoline-6-sulfonic acid) diamonium salt], TEAC [6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid (Trolox)-equivalent antioxidant capacity] assays have been used to evaluate antioxidant activity of honey. The antioxidant activity of honey is also measured by ascorbic acid content and different enzyme assays like Catalase (CAT), Glutathione Peroxidase (GPO), Superoxide Dismutase (SOD). Among the different methods available, methods that have been validated, standardized and widely reported are recommended.

Determining total phenolic content and total antioxidant capacity of loquat cultivars grown in Hatay

Several fruit characteristics of five loquat (Eriobotrya japonica (Thunb.) Lindl.) cultivars/selections grown in Dörtyol, Hatay, Turkey were investigated in 2008. The cultivars/selections included 'Baduna 5', Güzelyurt 1, 'Hafif Cukurgöbek', 'Ottaviani,' and Type 1. The characteristics evaluated included fruit weight, width, length, seed number and weight, flesh/seed ratio, total soluble solids (TSS), pH, acidity, total phenolic (TP) content, and total antioxidant capacity (TAC), determined by the ferric reducing antioxidant power (FRAP) assay. The analyses were conducted by three replicates, with 30 fruits in each replicate. The results indicated that there were significant differences among the cultivars, for all the traits tested. For example, 'Hafif Cukurgöbek' and 'Ottaviani' had smaller fruits than others, although 'Hafif Cukurgöbek' had heavier seeds. The flesh/seed ratio was the highest in Type 1, while 'Hafif Cukurgöbek' had the highest pH and high soluble solids. 'Baduna 5' and 'Hafif Cukurgöbek' had the highest acidity. The TP ranged from 129 ('Baduna 5') to 578 ('Hafif Cukurgöbek') mg gallic acid equivalent (GAE)/kg fresh fruit (fw). 'Hafif Cukurgöbek' also had the highest FRAP mean (12.1 mmol Trolox Equivalent (TE)/kg fw). The results suggest that loquat cultivars have a variable range of TP content and a relatively high total antioxidant capacity, which is crucial for human health.