Cupric Ion Reducing Antioxidant Capacity Research Articles

Phytochemical Characterization of Five Edible Purple-Reddish Vegetables: Anthocyanins, Flavonoids, and Phenolic Acid Derivatives.

Vegetables comprise a significant portion of our daily diet with their high content in nutrients including fiber, vitamins, minerals, as well as phenolic compounds. Vegetable consumption has been shown to be positively associated with the prevention of several degenerative diseases thanks to their bioactive compounds. Accordingly, five selected vegetables, namely, red chicory, red onion, eggplant, purple sweet potato, and black carrot were thoroughly assessed for their phenolic content in this study. For this purpose, the total phenolic and flavonoid content of these five vegetables and their antioxidant activities that are based on three common methods ABTS radical cation decolorization assay (ABTS), Cupric Ion Reducing Antioxidant Capacity (CUPRAC), and DPPH scavenging activity assay were determined. Additionally, HPLC-PDA/Electrospray ionization coupled with mass spectrometry (HPLC-PDA/-ESI+-MS)-based identification and quantification of the members belonging to polyphenols present in each vegetable were determined. Statistical correlations between antioxidant activities and the specific type of phenolic compounds, such as anthocyanins, flavonoids, anthocyanins, and phenolic acids were further elucidated. Phenolic acids (chlorogenic and syringic acids) were found to be the most abundant compounds that are present in all samples. Among the anthocyanins, cyaniding derivatives were present in all vegetables. In terms of their antioxidant activities, the analyzed vegetables were ranked as red chicory > purple sweet potato > black carrot > eggplant > red onion, in descending order. Superior antioxidant activities exhibited by red chicory and purple sweet potato were attributed to the high content of phenolic compounds, especially flavonols (quercetin-3,4-O-diglucoside) in red chicory and anthocyanins (peonidin-3-caffeoyl p-hydroxybenzoylsophoroside-5-glucoside) in purple sweet potato.

Optimization of Maceration Conditions for Improving the Extraction of Phenolic Compounds and Antioxidant Effects of Momordica Charantia L. Leaves Through Response Surface Methodology (RSM) and Artificial Neural Networks (ANNs)

The main goals of this research were the chemical and biological characterization of the bitter melon (Momordica charantia) isolate obtained by traditional (maceration) extraction, as well as optimization of this process using response surface methodology (RSM) and artificial neural networks (ANNs). Experiments were performed using Box–Behnken experimental design on three levels and three variables: extraction temperature (20 °C, 40 °C, and 60 °C), solvent concentration (30%, 50%, and 70%) and extraction time (30, 60, and 90 min). The measurements consisted of 15 randomized runs with 3 replicates in a central point. The antioxidant activity of obtained extracts was determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH), cupric ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) assays while chemical characterization was done in terms of the total phenolic content (TPC). The methodology shows positive influence of solvent concentration on all four observed outputs, while temperature showed a negative impact. RSM showed that the optimal extraction conditions were 20 °C, 70% methanol, and an extraction time of 52.2 min. Under these conditions, the TPCs were 20.66 milligrams of gallic acid equivalents (mg GAE/g extract), DPPH 30.22 milligrams of trolox equivalents (mg TE/g extract), CUPRAC 67.78 milligrams of trolox equivalents (mg TE/g extract), and FRAP 45.48 milligrams of trolox equivalents (mg TE/g extract). The neural network coupled with genetic algorithms (ANN-GA) was also used to optimize the conditions for each of the outputs separately. It is anticipated that results reported herein will establish baseline data and also demonstrate that that the present model can be applied in the food and pharmaceutical industries.

Determination of Cobalt(II)-Hydrogen Peroxide-Induced DNA Oxidative Damage and Preventive Antioxidant Activity by CUPRAC Colorimetry

The classical Fenton system composed of Fe(II) and H2O2 uses harsh oxidative conditions and cannot realistically simulate physiological oxidations which are less severe. Here, reactive oxygen species (ROS) were generated with a combination of CoSO4 and H2O2 to provide milder conditions. DNA was used as a biologically meaningful probe for monitoring the oxidative conversion. Oxidative hazard on DNA was accomplished in ammonia/ammonium chloride buffer at 37 °C, and the Fenton reaction was stopped with trichloroacetic acid (TCA). A suitable aliquot of this solution was added to cupric ion reducing antioxidant capacity (CUPRAC) reaction mixture, and the absorbance at 450 nm was recorded. The oxidized species derived from DNA were CUPRAC-reactive while intact DNA was not. The protective effects of antioxidants (AOxs), known to have radical scavenging effects, were tested; green tea and a synthetic fetal bovine serum (FBS) were also successfully used as real ROS scavengers. Although the classical iron-based Fenton procedure applied in ethanol medium generated CUPRAC-responsive products, the proposed system was perfectly ethanol-tolerant, enabling the CUPRAC measurement of DNA oxidation products against an unaffected reagent blank. The protective effects of phenolic antioxidants, perfectly solubilized in ethanol, could also be measured.

Human Semen Samples with High Antioxidant Reservoir May Exhibit Lower Post-Cryopreservation Recovery of Sperm Motility.

Cryopreservation-thawing of human semen was found to reduce the level of antioxidant activity surrounding the sperm, which may negatively affect post-cryopreservation (post-thaw) recovery of sperm motility. Therefore, the current manufactured cryoprotectant media have been supplemented with certain antioxidants to preserve the loss in seminal antioxidant activity. In this study, we aimed to explore the correlation between total antioxidant capacity (TAC) of human semen samples before cryopreservation and the post-thaw recovery of sperm motility. Normal semen specimens (n = 77) were recruited in this study. Sperm motility was measured for each semen sample before and after cryopreservation and the post-thaw recovery of sperm motility was calculated. Seminal TAC was measured spectrophotometrically before cryopreservation for each semen sample using the sensitive cupric ion-reducing antioxidant capacity (CUPRAC) method. The results from this study showed that the post-thaw recovery of sperm motility is negatively correlated (p = 0.0404, p = 0.0402) with the absorbance at 450 nm and the values of seminal TAC in terms of µM Trolox equivalents, as evaluated by CUPRAC, respectively. In conclusion, the total antioxidant reservoir in each ejaculated semen specimen could be a factor in determining the post-thaw recovery of sperm motility toward lower recovery for semen specimens of high antioxidant content.

Cobalt+Salt-Stressed Salvia officinalis: ROS Scavenging Capacity and Antioxidant Potency

Salvia officinalis L. (Lamiaceae) is one of the most widespread herbal species used in the food processing industry and for culinary and medicinal purposes. This work aimed to investigate changes in plant growth, water content, lipid peroxidation, H2O2, proline, and enzymes related to reactive oxygen species (ROS) detoxification including superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). Phenolic contents and antioxidant capacity values such as ferric ion reducing antioxidant power (FRAP), cupric ion reducing antioxidant capacity (CUPRAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging were studied under stress conditions of salt, cobalt and a combination of the two. No significant differences were found in relative water content and chlorophyll fluorescence under salt, cobalt and their combination. However, the osmotic potential and relative growth rate were enhanced with salt+cobalt compared to salt-treated plants. Salt and cobalt individually stimulated high antioxidant activity. High APX and GR activities were associated with the high proline accumulation in the sage plants under the combined effect of salt+cobalt. The combination decreased lipid peroxidation (TBARS), while H2O2 content was increased. This increase with the combined salt+cobalt effect may be associated with the decrease in CAT activity. Moreover, a strong correlation was found between TPC and TF content and antioxidant capacity measured via FRAP, CUPRAC and DPPH. The TPC, TF and antioxidant capacity values also increased under the salt+cobalt combination, suggesting an increase in antioxidant content in the sage leaves. Therefore, the combination of salt and cobalt improved the stress tolerance of S. officinalis.

Oxovanadium(IV) and ruthenium(II) carbonyl complexes of ONS‐donor ligands derived from dehydroacetic acid and dithiocarbazate: Synthesis, characterization, antioxidant activity, DNA binding and in vitro cytotoxicity

A series of new complexes of oxovanadium(IV) [VO(L)(B)] and ruthenium(II) [Ru(CO)(PPh3)2(L)] (1.1- 1.3, 2.1–2.3) (H2L = dehydroacetic acid Schiff base of S‐methyldithiocarbazate, H2smdha (1) or S‐benzyldithiocarbazate, H2sbdha (2); B = 2,2′‐bipyridine (bpy) or 1,10‐phenanthroline (phen)) have been synthesized. The structure of these complexes was authenticated using elemental analyses and spectroscopic techniques, and their magnetic properties and electrochemical behaviour were studied. The molecular structures of oxovanadium(IV) complexes [VO(smdha)(bpy)]⋅CH2Cl2 (1.1) and [VO(sbdha)(phen)]⋅2H2O (2.2) were confirmed using single‐crystal X‐ray crystallography. Analytical data showed that the ligands 1 and 2 are chelated to the metal centres in a bi‐negative tridentate fashion through azomethine N, thiol S and deprotonated hydroxyl group. The antioxidant activity of the synthesized compounds was tested against 2,2‐diphenyl‐1‐picrylhydrazyl) radical, which showed that the complexes demonstrate a better scavenging activity than their corresponding ligands. The cupric ion reducing antioxidant capacity method was also employed and the total equivalent antioxidant capacity values were found to be higher for the oxovandium(IV) complexes. DNA binding affinity of the compounds was determined using UV–visible and fluorescence spectra, revealing an intercalation binding mode. Higher cytotoxicity for the complexes compared to their ligands was found against human liver hepatocellular carcinoma (HepG2) and breast adenocarcinoma (MCF7) cell lines using MTT assay.

Hydroxytyrosol: The Phytochemical Responsible for Bioactivity of Traditionally used Olive Pits.

The fruits of Olea europaea L. is widely consumed as food, and olive pits are utilized in folk medicine to relieve gastric disturbances. In the present study, the possible anti-inflammatory, analgesic and antioxidant activities of aqueous extracts of black (BP) and green olive (GP) pit prepared at gastric fed state pH were evaluated in vitro. Moreover, the bioactive compound, hydroxytyrosol (HT), was isolated from the extracts for the first time. According to results, GP extract (62.5 to 1000 μg/mL) showed significant anti-inflammatory activity in a dose-dependent manner and HT displayed significant nitrite inhibition at 100 μM with slight analgesic activity. Extracts and HT showed a significant antioxidant activity according to Total Antioxidant Capacity (TOAC), cupric ion reducing antioxidant capacity (CUPRAC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. As a conclusion, a proper formulation containing HT might be a potential remedy to relieve gastric disturbances and olive pits, can be utilized as a valuable industrial tool for the low-cost production of HT.How to cite this article: Reis R, Sipahi H, Zeybekoglu G, Celik N, Kirmizibekmez H, Kaklikkaya N, Aydin A. Hydroxytyrosol: The Factor Responsible for Bioactivity of Traditionally used Olive Pits. Euroasian J Hepatogastroenterol, 2018;8(2):126-132.

Phenolic profiling and in vitro biological properties of two Lamiaceae species (Salvia modesta and Thymus argaeus): A comprehensive evaluation

The genus Salvia and Thymus have gained much popularity as an alternative therapy in Turkish folk medicine for abdominal pain, cold, nausea, among others. Nonetheless, some species are yet to be further explored for their bioactivities. We investigated the biological activities of 3 extracts (dichloromethane, methanol, and water (decoction)) of Salvia modesta Boiss. and Thymus argaeus (Fisch. & C.A.Mey.) Boiss. & Balansa. based on antioxidant and enzyme inhibition along with the determination of polyphenolic content. Antioxidant potential was assessed using six assays namely: 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), cupric ion reducing antioxidant capacity, ferric reducing antioxidant power, phosphomolybdenum, and metal chelating. Moreover, enzyme inhibition activities of the extracts were studied against acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase. Results revealed that the decoction of both plants was the strongest antioxidants. The methanol extracts displayed the highest tyrosinase inhibition while the dichloromethane extracts of both plants were the most effective butyrylcholinesterase and α-glucosidase inhibitors. In addition, the total phenolic and total flavonoid content was highest in the decoction and methanolic extract of Thymus argaeus, respectively. The most abundant phenolic compound was rosmarinic acid (6574 μg/g and 5390 μg/g in T. argaeus and S. modesta methanolic extracts, respectively). PASS prediction analysis revealed that chlorogenic acid showed the highest Pa value for antioxidant activity (0.809) including the mechanism of free radical scavenging (0.856), while rosmarinic acid showed the highest Pa value (0.798) for antidiabetic activity. To conclude, both Salvia modesta and Thymus argaeus can be regarded as new sources of antioxidants and enzyme inhibitors to manage oxidative stress and their complications.

In vitro therapeutic correlative studies of Pandanus odoratissimus flowers against diabetic foot ulcer-causing bacterial pathogens

Background: Diabetic foot ulcer (DFU) is a major secondary complication that arouses subsequently due to careless of patient in poor therapeutic management of chronic diabetes. This may sometimes lead to amputation of foot which creates mental stress and societal empathy among diabetic patients. Hence, the aim of the present investigation is formulated to evaluate and correlate the in vitro antioxidant efficacy, in vitro invertase inhibitory activity and in vitro antibacterial activity of Pandanus odoratissimus flower extracts. Materials and Methods: In vitro cupric ion reducing antioxidant capacity and 1, 1-diphenyl-2- picrylhydrazyl (DPPH) assays were performed to analyze the reducing power and radical scavenging property of P. odoratissimus flower extracts. Standard broth dilution and agar well diffusion assays were espoused for antibacterial activity. Similarly, DNS method is adopted to investigate the invertase inhibitory activity. Results and Discussion: The bacterial pattern identification studies carried out with the clinical isolates (pus and blood) of DFU patients have revealed the presence of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The methanol (12 ± 3 mm) and acetone (16 ± 4 mm) crude extracts possessed significant zone of inhibition against E. coli, and near satisfactory control was observed against S. aureus and P. aeruginosa. Significant dipicryl ion scavenging activity (DPPH) was recorded by methanolic (90.7 ± 2%) and aqueous extracts (81.4 ± 3%). Similarly, a satisfactory cupric ion reducing property was established by the methanolic (effective dosage [ED50]: 455.3 ± 8 μg/ml) and aqueous extracts (ED50: 452.14 ± 5 μg/ml). An effective in vitro invertase inhibitory activity (62.5 ± 3%) was recorded by methanolic extract. Conclusion: The studies proved a strong correlation exist between antioxidant power, invertase inhibition, and control against DFU causing bacterial pathogens recorded by P. odoratissimus flower extracts which promise it is application as a sustainable traditional medicine against DFU.

Glutathione Peroxidase Activity of Biological Samples Using A Novel Microplate-Based Method

Background: Glutathione peroxidase (GSH-Px) is one of the major enzyme in the antioxidative defense mechanism present in the cells. Methods: In the present study a novel and simple microplate-based method was developed, using the cupric neocuproine complex (Cu(Nc)2 2+) as a chromogenic oxidizing reagent, for the assessment of GSH-Px activity of biological samples for the first time. In this GSH-Px enzyme activity measurement, the GSH-Px catalyzed oxidation of Reduced Glutathione (GSH) gives rise to oxidized form of GSH (GSSG). The recommended method was based on the reduction of Cu(Nc)2 2+ to highly colored Cu(I)- neocuproine complex (Cu(Nc)2 +) by the unconsumed GSH, and measurement spectrophotometrically at 450 nm, the difference being correlated to GSH-Px activity of the analytes. Results: Under the optimum conditions, a linear calibration graph was obtained in the range of 18.5- 92.5 µM of GSH with Limit Of Detection (LOD) of 1.03 µM. Application of developed method to tissue homogenates (n = 9) provided GSH-Px activity values in agreement with those of the reference GSH-Px-5,5’-dithio-bis(2-nitrobenzoic acid) (DTNB) method. Conclusion: Cupric Ion Reducing Antioxidant Capacity (CUPRAC) antioxidant method was implemented in a microformat (96 well plates) and the reaction time of original CUPRAC method was significantly shortened from 30 to 4 min. Multi-sample can be simultaneously detected thanks to a novel microplate method. Keywords: GSH-Px activity, microplate based method, modified CUPRAC method, biological samples, neocuproine complex, reduced glutathione (GSH).

HPLC Analysis of Phenolic Compounds from Gypsophila aucheri Boiss. and Investigation of Antioxidant and Cytotoxic Activity of Gypsophila aucheri Boiss. exracts

This study was designed to investigate the antioxidant and antiproliferative activities of Gypsophila aucheri Boiss. extracts as well as phenolic content by RP-HPLC technique. Antioxidant activity potentials of the extracts were evaluated by four different methods namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity tests, cupric ion reducing antioxidant capacity (CUPRAC) method, and metal chelating assay. Antiproliferative activities of the extracts were tested against breast carcinoma (MCF-7), colorectal carcinoma (HT-29), and hepatocellular carcinoma (HepG2) cells. RP-HPLC analysis revealed the presence of eight phenolic compounds in eighteen phenolics scanned. Antioxidant activity results showed that methanol extract of Gypsophila aucheri displayed more pronounced antioxidant activity than water extract according to DPPH and ABTS tests, whereas water extract was superior than methanol extract for CUPRAC and metal chelating activity tests. Cytotoxicity tests demostrated the promising antiproliferative activity of methanol extract against all the tested cancer cell lines with its lower IC50 values. However, both extracts were observed to display moderate biological activity compared to positive controls. The obtained data suggest that Gypsophila aucheri could be evaluated as a promising source for food and nutraceutical industries due to its striking antioxidant and moderate antiproliferative potentials together with high phytochemical profile

In vitro evaluation of antioxidant and anti-proliferative activities of Gypsophila sphaerocephala (Caryophyllaceae) extracts together with their phenolic profiles

This study was designed to investigate the antioxidant and antiproliferative activities of water and methanol extracts of endemic plant Gypsophila sphaerocephala subsp cappadocica in conjuction with phenolic profiles. Individual phenolics of the extracts were identified and quantified by RP-HPLC analysis. Antioxidant potentials of the extracts were evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS [2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging capacity tests, cupric ion reducing antioxidant capacity (CUPRAC) method and Fe2+ chelating assay. Antiproliferative activities of the extracts were tested against MCF-7 (breast adenocarcinoma), HT-29 (colorectal adenocarcinoma) and HepG2 (hepatocellular carcinoma) cell lines. RP-HPLC analysis showed that methanol extract was richer than water extract in terms of phenolic content. In parallel to the phenolic contents, methanol extract showed higher antioxidant activity than water extract by DPPH, CUPRAC and Fe2+ chelating tests while water extract exhibited higher activity by ABTS method. Moreover, methanol extract displayed 1.8-fold, 4.3-fold and 2.6-fold more antiproliferative activity than water extract against MCF-7 cells, HepG2 cells and HT-29 cells, respectively. However, both extracts were found to show moderate antioxidant and antiproliferative activity compared to positive controls. These results suggest that Gypsophila sphaerocephala may be used as a promising source for food and nutraceutical industries due to its considerable antioxidant and antiproliferative potentials together with its rich phenolic content.

Origanum vulgare ssp. vulgare: Chemical Composition and Biological Studies.

The biological properties and main phenolic compounds of the O. vulgare L. ssp. vulgare extract are described in the present paper. The polyphenolic compounds were analyzed by chromatographic and spectrophotometric techniques. The antioxidant potential was evaluated using several methods: CUPRAC (cupric ion reducing antioxidant capacity), FRAP (ferric reducing ability of plasma), inhibition of lipid peroxidation catalyzed by cytochrome c, and superoxide (SO) scavenging assays. The antimicrobial activity of the oregano extract was evaluated by means of agar-well diffusion assay. The hepatoprotective effect of the O. vulgare extract on CCl4-induced hepatotoxicity was evaluated in rats. Liver injury was estimated by determination of alanine aminotransaminase (ALT), aspartate aminotransaminase (AST), gamma-glutamyl transferase GGT, total protein and albumin concentrations, glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA). These values were improved by the administration of oregano extract. A specific phenolic profile was evidenced by these data, with large amounts of rosmarinic and chlorogenic acids. The oregano extract showed very strong antioxidant activity in good agreement with the phenolic content. Antimicrobial activity was good, especially against Salmonella enteritidis and Aspergillus niger strains. The high hepatoprotective, antioxidant and antimicrobial activity, along with polyphenol-rich content, can support the use of O. vulgare in therapy. We also expect our results to open new research directions for designing important new drug products, using indigenous plant material.

Antioxidant Potential of Indian Eggplant: Comparison Among White, Purple and Green Genotypes Using Chemometrics

Twenty-six eggplant genotypes of different colours were evaluated for their variations in total phenolics, total flavonoids, total monomeric anthocyanin and antioxidant activity. Antioxidant potentiality was determined using two in vitro assays, viz. cupric ion reducing antioxidant capacity and 2, 2-diphenyl-1-picrylhydrazyl (DPPH). Additionally, five colour attributes were evaluated. Among the eggplant genotypes, significant differences (p < 0.05) were observed with respect to antioxidant composition and antioxidant activity. Total phenolics and total flavonoids varied from 13.00 to 49.29 mg/100 g fresh weight (FW) and 5.30 to 28.70 mg/100 g FW, respectively. Chemometric tools such as principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were used to understand the possible classification of Indian eggplant genotypes based on their colour properties, antioxidant composition and antioxidant potentiality. PCA revealed that the first two components represented 80.68% of the total variability in the total variation. AHC classified genotypes into three main groups on the basis of the measured parameters. A white-coloured genotype was found to be the richer source of phenolics and flavonoids with high antioxidant activity.

Antioxidant Capacity and Physicochemical Characteristics of Carbonated Erica Arborea Tea Beverage

The current study was aimed to generate an innovative tea beverage which has water infusion of Erica arborea. Dehydrated Erica arborea leaves were extracted in boiling water and the solution was brix value-balanced to 8° with sucrose, acid, natural lemon flavor, and antimicrobial agents. Following the blending of additives, carbonation was applied. Besides some physicochemical parameters, total phenolics, bioaccessibility of total phenols, antioxidant capacity, and bioaccessible antioxidants with 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and cupric ion reducing antioxidant capacity assay (CUPRAC) methods were also investigated. The green- and yellow-tinted beverage was especially rich in potassium and calcium. The total phenolics and bioaccessible phenolics of the beverage were identified as 174.06 ± 24.53 mg Gallic Acid Equivalent (GAE) 100 mL−1 and 96.07 ± 3.96 mg GAE 100 mL−1, correspondingly. Antioxidant capacity was 27.20 ± 1.09 μmol trolox mL−1, and the bioaccessible antioxidant capacity was 0.17 ± 0.02 μmol trolox mL−1 in DPPH. Measured antioxidant capacity and bioaccessible antioxidant capacity with other assays were 22.41 ± 2.49 and 3.09 ± 0.44 μmol trolox mL−1 for FRAP; 21.09 ± 1.65 and 0.02 ± 0.00 μmol trolox mL−1 for CUPRAC. In addition to its nutritional and functional features, Erica arborea tea beverage is preferred in accordance with the panelists’ sensorial decision.

Screening of the most consumed beverages and spices for their bioactive non-nutrient contents

The present research emphasizes on the bioactive non-nutrient components of the frequently consumed food products daily. The most popular beverages (instant, filter and Turkish coffee, green, black, sage, apple, rosehip, linden and fennel tea infusions) and herbal spices (cinnamon thyme, cumin, mint, sweet pepper, chili pepper, sumac, black pepper and clove) were investigated to evaluate the antioxidant capacities of the samples. Amount of total biophenols (TB) and total flavonoids (TF) were measured by Folin–Ciocalteu and Aluminum chloride colorimetric methods, respectively. CUPRAC (The cupric ion reducing antioxidant capacity) assay and DPPH (α, α-diphenyl-β-picrylhydrazyl) free radical scavenging method were applied to determine the antioxidant activity (AA) of the products. Antimicrobial analyses of the samples were also conducted based on in vitro study. Furthermore, the main biophenol of each sample was identified through high performance liquid chromatography (HPLC). The outcome of the present study will be a useful guidance for the researchers looking for the health benefits of these daily consumed food products.

Evaluation of antioxidant capacity of endemic plant Marrubium astracanicum subsp. macrodon: Identification of its phenolic contents by using HPLC-MS/MS

Antioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both cupric ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the composition and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentrations of quinic acid, p-coumaric acid and malic acid were determined.

Single Laboratory Validation of a Quantitative Core Shell-Based LC Separation for the Evaluation of Silymarin Variability and Associated Antioxidant Activity of Pakistani Ecotypes of Milk Thistle (Silybum Marianum L.)

Fruits of Silybum marianum (L.) Gaernt are the main source of taxifolin derived flavonolignans. Together, these molecules constitute a mixture called silymarin with many useful applications for cosmetic and pharmaceutic industries. Here, a validated method for the separation of the silymarin constituents has been developed to ensure precision and accuracy in their quantification. Each compound was separated with a high reproducibility. Precision and repeatability of the quantification method were validated according to the AOAC recommendations. The method was then applied to study the natural variability of wild accessions of S. marianum. Analysis of the variation in the fruits composition of these 12 accessions from Pakistan evidenced a huge natural diversity. Correlation analysis suggested a synergistic action of the different flavonolignans to reach the maximal antioxidant activity, as determined by cupric ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) assays. Principal component analysis (PCA) separated the 12 accessions into three distinct groups that were differing from their silymarin contents, whereas hierarchical clustering analysis (HCA) evidenced strong variations in their silymarin composition, leading to the identification of new silybin-rich chemotypes. These results proved that the present method allows for an efficient separation and quantification of the main flavonolignans with potent antioxidant activities.

π-π Conjugation Enhances Oligostilbene's Antioxidant Capacity: Evidence from α-Viniferin and Caraphenol A.

α-Viniferin and caraphenol A, the two oligostilbenes, have the sole difference of the presence or absence of an exocyclic double bond at the π-π conjugative site. In this study, the antioxidant capacity and relevant mechanisms for α-viniferin and caraphenol A were comparatively explored using spectrophotometry, UV-visible spectral analysis, and electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC–ESI–Q–TOF–MS/MS) analysis. The spectrophotometric results suggested that caraphenol A always gave lower IC50 values than α-viniferin in cupric ion-reducing antioxidant capacity assay, ferric-reducing antioxidant power assay, 1,1-diphenyl-2-picryl-hydrazl radical (DPPH•)-scavenging, and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical-scavenging assays. In UV-visible spectra analysis, caraphenol A was observed to show enhanced peaks at 250–350 nm when mixed with Fe2+, but α-viniferin exhibited no similar effects. UPLC–ESI–Q–TOF–MS/MS analysis revealed that α-viniferin mixed with DPPH• produced radical adduct formation (RAF) peak (m/z = 1070–1072). We conclude that the antioxidant action of α-viniferin and caraphenol A may involve both redox-mediated mechanisms (especially electron transfer and H+-transfer) and non-redox-mediated mechanisms (including Fe2+-chelating or RAF). The π-π conjugation of the exocyclic double bond in caraphenol A can greatly enhance the redox-mediated antioxidant mechanisms and partially promote the Fe2+-chelating mechanism. This makes caraphenol A far superior to α-viniferin in total antioxidant levels.

Effects of Orange Leaves Extraction Conditions on Antioxidant and Phenolic Content: Optimization Using Response Surface Methodology

ABSTRACTIn the last few years, bioactive components or their extraction techniques are gaining special interest in scientific areas. In this framework, orange leaves were used for preparation of extracts with high content of biologically active compounds. To optimize the extraction process, three levels and three variables of Box–Behnken design with response surface methodology were applied. Investigated responses were the total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, cupric ion reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP). Independent variables were methanol concentration (10–90%), temperature (20–60°C), and extraction time (60–180 min). Experimentally obtained results were fit into a second-order polynomial model with multiple regression. Analysis of variance was used to estimate model fitness and determine optimal conditions for processing. Estimated optimal conditions were 90% methanolic solution, 60°C and 180 min using these parameters; the predicted values of investigated responses were 43.19 mg GAE/g (GAE: gallic acid equivalents), 43.04 mg TE/g (TE: trolox equivalents), 139.34 and 93.76 mg TE/g for TPC, DPPH, CUPRAC, and FRAP, respectively. The obtained optimal conditions could be considered as an alternative strategy for developing novel functional products.