Trolox Equivalent Antioxidant Capacity Research Articles

Calafate (Berberis microphylla G. Forst) Populations from Chilean Patagonia Exhibit Similar Structuring at the Genetic and Metabolic Levels

Berberis microphylla, commonly known as calafate, is one of the most promising species of Chilean Patagonia to be domesticated, due to its anthocyanin-rich berries. The main aim of this study was to understand the genetic structure of the wild populations of B. microphylla in the main regions where it grows and its relationship with phenolic secondary metabolite profiles. Ripe berry samples and leaves were collected from the Aysén and Magallanes regions. Genetic analyses were carried out using 18 microsatellite markers. Phenolic compounds were extracted from the ripe fruits and were quantified using high-performance liquid chromatography (HPLC). Their antioxidant capacity was determined according to the Trolox equivalent antioxidant capacity (TEAC) assay. Total phenols were measured as their absorbance at a wavelength of 280 nm. Both the genetic and chemometric data were explored using unsupervised and supervised methods. The genetic markers suggest the existence of three groups, two of them corresponding to the Aysén and Magallanes samples, and the third corresponding to Chile Chico (a district in Aysén), which was the most divergent of the three. Similar results were observed in the phenolic profile obtained with chemometric analysis, with the same samples forming a separate third group. The differentiation achieved using the genetic and chemical data may be the result of intrinsic genetic differences, environmental effects on fruit maturity, or the sum of both factors. These are all points to consider in the domestication of this valuable species by selecting individuals with desirable traits and contrasting phenotypes.

Investigation into the role of carboxylic acid and phenolic hydroxyl groups in the plant biostimulant activity of a humic acid purified from an oxidized sub-bituminous coal

IntroductionHumic substances (HS) are increasingly being applied as crop plant biostimulants because they have been shown to increase plant productivity, especially under environmentally stressful conditions. There has been intense interest in elucidating the HS molecular structures responsible for eliciting the plant biostimulant response (PBR). The polar and weakly acidic carboxylic (COOH) and phenolic hydroxyl (ArOH) functional groups play major roles in the acid nature, pH dependent solubilities, conformation, and metal- and salt-binding capabilities of HS. Reports on the role played by these groups in the PBR of HS found growth parameters being both positively and negatively correlated with COOH and ArOH functionalities.Materials and methodsTo investigate the role of COOH and ArOH in HS biostimulant activity we used a humic acid (HA), purified from an oxidized sub bituminous coal to prepare HAs with COOH groups methylated (AHA), ArOH groups acetylated (OHA), and with both COOH and ArOH groups methylated (FHA). The original HA was designated (NHA). The four HAs were subjected to elemental, 13C-NMR, FTIR, and EPR analyses and their antioxidant properties were assessed using the trolox equivalents antioxidant capacity assay (TEAC). 13C-NMR and FTIR analysis revealed significant alkylation/acetylation. To determine the effects of alkylating/acetylating these functional groups on the HA elicited PBR, the HAs were evaluated in a plant bioassay on corn (Zea mays L.) seedling under nutrient and non-nutrient stressed conditions. Treatments consisted of the four HAs applied to the soil surface at a concentration of 80 mg C L−1, in 50 ml DI H2O with the control plants receiving 50ml DI H2O.ResultsThe HA-treated plants, at both fertilization rates, were almost always significantly larger than their respective control plants. However, the differences produced under nutrient stress were always much greater than those produced under nutrient sufficiency, supporting previous reports that HA can reduce the effects of stress on plant growth. In addition, for the most part, the HAs with the alkylated/acetylated groups produced plants equal to or larger than plants treated with NHA.ConclusionThese results suggests that COOH and ArOH groups play a limited or no role in the HA elicited PBR. Alternatively, the HA pro-oxidant to antioxidant ratio may play a role in the magnitude of the biostimulant response.

Antioxidant polypeptides derived from pigeon pea (Cajanus cajan (L) Mill sp.) by enzymatic hydrolysis

Pigeon pea (Cajanus cajan (L) Mill sp.) seeds are rich sources of protein in the legume family and their consumption has been associated with the prevention of noncommunicated diseases, which is attributable to their content of bioactive components. Antioxidant protein hydrolysates were produced from pigeon pea protein isolate (PPI) by enzymatic hydrolysis using pancreatin and flavourzyme. The hydrolysates were analyzed for their physicochemical, molecular weight, amino acid composition, and in vitro antioxidant activities. The molecular weights of polypeptides in the hydrolysates were 8, 20, 25 and 48 kDa, which were determined after pancreatin or flavourzyme hydrolysis of the protein isolate for 4 h. Pancreatin-hydrolyzed pigeon pea protein (PPHP) contained high hydrophobic amino acids, especially isoleucine, leucine and valine, which were related to the high content of aromatic amino acids. The hydrolysates obtained from flavourzyme hydrolysis of pigeon pea proteins (PPHF) presented significantly higher capacities to scavenge ABTS˙+ and reduce Fe3 + better than that of PPI, while the PPI exhibited strong DPPH scavenging (98.4 mg trolox equivalent antioxidant capacity). The results indicated that the partial hydrolysis for PPI provided medium to high molecular weight of peptides. Therefore, PPHF could be a promising source of bioactive peptides and a potential ingredient for the formulation of functional foods against oxidative stress

Changes in biomarkers of the redox status in whole blood and red blood cell lysates in canine hypothyroidism.

Hypothyroidism is the most commonly diagnosed endocrine disease in dogs. The objective of this study was to evaluate the changes in the redox status in canine hypothyroidism using whole blood (WB) and red blood cell (RBCs) lysates. For this purpose, a panel of five antioxidants and five oxidants biomarkers was measured in WB and RBCs lysates of 30 dogs with hypothyroidism, 26 dogs with non-thyroidal illnesses and 15 healthy dogs. The antioxidants measured were cupric reducing antioxidant capacity (CUPRAC), ferric reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), thiol and paraoxonase type-1 (PON-1). Oxidants measured include the total oxidant status (TOS), peroxide-activity (POX-Act), reactive oxygen-derived metabolites (d-ROMs), advanced oxidation protein products (AOPP) and thiobarbituric acid reactive substances (TBARS). WB showed a significant decrease of the antioxidants CUPRAC, TEAC and thiol, and also an increase in TBARS and a decrease in AOPP in dogs with hypothyroidism compared to healthy dogs. Meanwhile, RBCs lysates showed a significant increase in FRAP and PON-1 in dogs with hypothyroidism. The changes in the redox biomarkers in this study show that WB in canine hypothyroidism had a higher number of changes in biomarkers of the redox status than RBCs lysates, making it a promising sample type for the evaluation of the redox status in this disease. In addition, WB is easier and simpler to process than RBCs lysates and unlike serum, it does not have any hemolysis interference.

Physicochemical, Antioxidant, Antimicrobial, and Sensory Characteristics of Selected Kinds of Edible Oils

The aim of this study was to determine the peroxide values, acid numbers, oxidative stability (Rancimat method), antioxidant activity (DPPH method), antimicrobial activity (disc diffusion method), sensory properties (9-point hedonic scale), and fatty acid profiles (FAME) of five edible oils purchased from local Slovakian producers—grape seed oil, flax seed oil, walnut oil, poppy seed oil, and milk thistle seed oil. The peroxide value ranged from 2.27 (milk thistle oil) to 8.51 (flax seed oil) mmol O2/kg. All these values were in accordance with regulations (upper limit of 20 mmol O2/kg). The values of the acid number ranged from 0.11 (walnut oil) to 2.49 (milk thistle oil) mg KOH/g, and were in accordance with regulations as they did not exceed the value of 4 mg KOH/g. The oxidation stability was the lowest in flax seed oil (0.18 h) and the highest in grape seed oil (2.05 h). In milk thistle oil, the highest amounts of oleic and behenic acids, in flax seed oil, the highest amount of α-linolenic acid, and in grape seed oil, the highest amount of linolic acid were determined. Antioxidant activity was the strongest in the sample of grape seed oil—65.53 mg TEAC/L (Trolox equivalent antioxidant capacity). Samples of flax seed oil showed the strongest inhibition of Candida albicans CCM 8186 (4.58 mm) and Bacillus subtilis CCM 2010 (0.31 mm). Poppy seed oil was determined to be the most inhibiting towards Klebsiella pneumoniae CCM 2318 (3.68 mm). Milk thistle oil showed the strongest inhibition of Clostridium perfringens CCM 4435 (6.31 mm). Grape seed oil was the most inhibitory towards Staphylococcus aureus subs. aureus CCM 2461 (5.32 mm). Walnut oil showed the strongest activity towards Yersinia enterocolitica CCM 5671 (6.33 mm). The sensory analysis resulted in the samples of walnut and grape seed oil being awarded the highest scores for smell, taste, and overall acceptability. The tested edible oils are rich in biologically active compounds with antioxidant and antimicrobial activities. Their consumption can have a positive effect on the functioning of the human body and its health. Proper storage conditions are, however, necessary because of the susceptibility of these oils to oxidation.

Natural deep eutectic liquid and ultrasound-assisted extraction of milk thistle phenolics and their hepatoprotective activities

IntroductionThe present research describes the utilization of natural deep eutectic solvent in combination with ultrasound for the extraction of milk thistle polyphenols. The extracts obtained under different conditions were evaluated for their in vitro antioxidant activities and hepatoprotective activities in Albino mice (in vivo).MethodsThe extraction parameters involving liquid-to-solid ratio (S/L), ethanol-to-natural deep eutectic solvent ratio (EtOH/DES), extraction time (t), and ultrasound treatment time were investigated and optimized to enhance the recovery of bioactives, their phenolic content, Trolox equivalent antioxidant capacity (TEAC), and radical scavenging capacity (RSC).Results and discussionsThe extraction of milk thistle polyphenols using glucose/citric acid (1:1)-based natural deep eutectic liquid coupled with ultrasound for 1.0 min under an S/L of 6.2, EtOH/DES 9, and extraction time of 120.8 min offered 35.89 ± 2.29 g/100 g of crude extracts, which were three-fold higher than that by conventional solvent extraction (CSE). Each gram of milk thistle extracts thus obtained comprised 377.93 ± 6.17 mg GAE of TPC and exhibited 298.70 ± 3.06 μmol TEAC and 93.16 ± 0.58 percent inhibition of DPPH free radicals. In addition, the administration of milk thistle extracts obtained as given above at 25 mg/Kg body weight in Albino mice significantly (p ≤ 0.05) improved the liver function parameters at the end of treatment (7 days).ConclusionOverall, it was observed that NaDES in combination with medium-level ultrasound energy (700 watt) might work as a sustainable choice to enhance the recovery of bioactive phenolics from milk thistle powder without compromising their antioxidant and hepatoprotective potential.

Changes in antioxidant properties of pepper leaves (Capsicum annuum L.) upon UV radiation

Bell pepper (Capsicum annuum) is one of the most popular vegetables consumed worldwide. The leaves of pepper are rich in phenolics, including phenolic acids and flavonoids. These compounds are well known for their ultraviolet (UV) absorbing and antioxidant properties. While the change of the phenolic pattern is an intensive research subject, it is not yet well-known in pepper leaves, particularly in outdoor conditions. In this experiment, we examined the effect of UV radiation on the leaves of outdoor grown peppers, focusing on the UV-absorbing properties and antioxidant capacities. Three different total antioxidant capacity (TAC) measurements have been compared: (I) Folin-Ciocalteu Reactivity (FC), (II) Ferric Reducing Antioxidant Power (FRAP) and (III) Trolox Equivalent Antioxidant Capacity (TEAC). Moreover, non-enzymatic hydrogen peroxide scavenging antioxidant capacity was measured. Significant increase was detected only in FRAP, suggesting an elevation exclusively in the level of phenolic acids in case of UV exposed outdoor grown pepper leaves.

Exploring the Influence of Origin, Harvest Time, and Cultivation Method on Antioxidant Capacity and Bioactive Compounds of Matcha Teas.

Matcha, or powdered green tea, has been gaining popularity and is no longer consumed only in the form of infusions, finding new uses in gastronomy and the food industry. The range of teas available on the food market has expanded considerably; hence, the aim of this study was to determine, for the first time, the antioxidant capacity and contents of antioxidant compounds in various Matcha teas available on the Polish market, taking into account the country of origin, time of harvest, and conventional vs. organic cultivation. Eleven green-tea powders were used in the analyses performed using spectrophotometric methods (Trolox equivalent antioxidant capacity, Ferric-Ion-Reducing Antioxidant Power, Total Polyphenol Content, Total Flavonoid Content, Vitamin C Content) and HPLC methods (polyphenolic acids, flavonoids, and caffeine). Antioxidant capacity ranged from 7.26 to 9.54 mM Trolox equivalent/L while reducing power ranged from 1845.45 to 2266.12 Fe(II)/L. Total phenolic content amounted to 820.73-1017.83 mg gallic acid equivalent/L, and total flavonoid content was 864.71-1034.40 mg rutin equivalent /L. A high vitamin C content was found, ranging from 38.92 to 70.15 mg/100 mL. Additionally, a high content of caffeine that ranged between 823.23 and 7313.22 mg/L was noted. Moreover, a high content of polyphenolic compounds, including epicatechin gallate, myricetin, gallic acid, and 4-hydroxybenzoic acid, was found. The phytochemical composition and antioxidant properties depended on the harvest time, type of cultivation, and country of origin. Therefore, Matcha tea infusions have been shown to be a valuable source of antioxidants that can be used in the daily diet.

Analysis of light recipe, seeding density, and fertilization effects on secondary metabolite accumulation and growth-defense responses in Brassicaceae microgreens

Although there have been large improvements to crop yield over time, this has not been accompanied by an increase in human nutritional wellbeing. In fact, there are worsening health crises associated with over- and under-consumption of particular food groups, resulting in negative human health outcomes. One solution to this is to utilize controlled environment agriculture to produce microgreens that have a high density of valuable Secondary Metabolites (SMs) such as antioxidants, phenolics, or pigment molecules that are associated with positive human health outcomes. However, optimal growth recipes to produce microgreens and their valuable nutritional compounds are not well known due to much species-specific variation, as well as biological tradeoffs between biomass and SM production. This is known as the growth defense hypothesis which describes how plants have a finite carbon budget from which to allocate to growth, or defensive, processes. To further research in this regard, this project used climate chambers to grow three species of Brassicaceae microgreens (kohlrabi, mustard, and radish) in highly controlled environmental conditions, where we used five Light Recipes, two fertilization levels, and two seeding density treatments. Our results showed that there were significant differences in SM production of these microgreens due to changes in incident light, as well as significant interactions between Fertilizer and Light Recipe for all SMs except Anthocyanins. For example, for all three species, the High Far-Red Light Recipe had the significantly highest Phenolic concentration, but with lower values of the other four SMs. The low-intensity 24-volt high efficiency LEDs had the significantly highest Trolox Equivalent Antioxidant Capacity (TEAC) concentrations, while the High Red recipe had the highest Ferric Reducing Antioxidant Power (FRAP) and Flavonoid concentrations. For Anthocyanins, there were less clear patterns, with the No Green or High Red recipes having generally higher concentrations, but not always significantly. We did find some evidence supporting the growth-defense hypothesis, where our higher biomass values were negatively correlated with SM concentrations. We also found significant differences between the concentrations of SMs in leaves and stems for kohlrabi and mustard microgreens. Finally, we found some significant relationships between increasing Fertilizer dosage and SMs, for instance that Flavonoids and FRAP concentrations increased with Fertilizer application, while Anthocyanin decreased, and Phenolic and TEAC had little effect. In conclusion, we found that there were significant relationships for Light Recipe and Fertilizer, and oftentimes their interaction, for the accumulation of SMs in Brassicaceae microgreens, which can inform microgreen production environments.

Bio-clay: Antioxidant-rich and stable for body mud scrubs

Clay is naturally occurring and poses a low risk. It is distinguished by mineral composition and ability to adsorb plant colorants and phytochemicals effectively. This study aimed to enhance the stability of bio-clay by preparing body mud scrubs through a solid-state reaction, combining volcanic clay with herbal plants, including Bougainvillea spp., Pandanus amaryllifolius Roxb., and Curcuma longa L. (bio-clay). The characterization of purification clay revealed strong stability within its mineral composition. The optimum condition for sampling was 4 °C, which reserved the total phenolic content (TPC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. A high Trolox equivalent antioxidant capacity (TEAC; mg TEAC/g sample) and low half-maximal inhibitory concentration (IC50) indicated excellent antioxidant activity. Over a storage period of 28 d, the Bougainvillea spp., Curcuma longa L., purified clay + Bougainvillea spp., and purified clay + Curcuma longa L. samples retained their stability. Their TPC, % scavenging, TEAC, and IC50 showed dominant antioxidant activity, stable active phenolic compounds, and the maintenance of extensive amounts. This compound is widely applied as a unique cosmetic ingredient.

Investigation of the sensory quality, nutritional value and antioxidant capacity of flakes prepared using various pigeon pea-based flours

Pigeon pea (Cajanus cajan (L.)) is a potential source of nutritional and antioxidant compounds. Germination proved to improve the nutritional quality and antioxidant capacity of pigeon peas. The previous author’s study showed that pigeon pea flour prepared by NaCl elicitation before germination exhibits significantly higher antioxidant capacity and functional properties than that prepared without elicitation or germination. The study aimed to examine the sensory quality, nutrition value, and antioxidant capacity of flakes formulated using non-germinated pigeon pea flour, pigeon pea sprout flour, and NaCl-elicited pigeon pea sprout flour. The potential of the flours to be developed as commercial flakes was also determined using oat-based commercial flakes as a comparator. The NaCl-elicited pigeon pea flour-based flakes showed a higher quality score of both texture and overall qualities than the other pigeon pea flour-based flakes and the commercial ones. Regarding nutritional value, flakes formulated using NaCl-elicited pigeon pea sprout flour also showed better nutritional value, indicated by the lowest fat content and highest soluble, insoluble, and total dietary fiber contents. The highest values of total phenolics content (TPC), Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) were also observed in the NaCl-elicited pigeon pea sprout flour-based flakes, even though its DPPH radical scavenging activity was not significantly different to the commercial flakes. These results have significant consequences for developing legume-based flakes with higher levels of dietary fibers and antioxidant potential, and lower fat content.

Exploring the Chemical Profile, In Vitro Antioxidant and Anti-Inflammatory Activities of Santolina rosmarinifolia Extracts.

In this study, the phytochemical composition, in vitro antioxidant, and anti-inflammatory effects of the aqueous and 60% ethanolic (EtOH) extracts of Santolina rosmarinifolia leaf, flower, and root were examined. The antioxidant activity of S. rosmarinifolia extracts was determined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The total phenolic content (TPC) of the extracts was measured by the Folin-Ciocalteu assay. The anti-inflammatory effect of the extracts was monitored by the Griess assay. The chemical composition of S. rosmarinifolia extracts was analysed using the LC-MS technique. According to our findings, 60% EtOH leaf extracts showed the highest Trolox equivalent antioxidant capacity (TEAC) values in both ABTS (8.39 ± 0.43 µM) and DPPH (6.71 ± 0.03 µM) antioxidant activity assays. The TPC values of the samples were in good correspondence with the antioxidant activity measurements and showed the highest gallic acid equivalent value (130.17 ± 0.01 µg/mL) in 60% EtOH leaf extracts. In addition, the 60% EtOH extracts of the leaves were revealed to possess the highest anti-inflammatory effect. The LC-MS analysis of S. rosmarinifolia extracts proved the presence of ascorbic acid, catalpol, chrysin, epigallocatechin, geraniol, isoquercitrin, and theanine, among others, for the first time. However, additional studies are needed to investigate the direct relationship between the chemical composition and physiological effects of the herb. The 60% EtOH extracts of S. rosmarinifolia leaves are potential new sources of natural antioxidants and anti-inflammatory molecules in the production of novel nutraceutical products.

Determination of essential oil and chemical composition of St. John’s Wort

Abstract Considering it contains a variety of physiologically active compounds, including flavonoids, common phenols, and essential oils (EOs), St. John’s wort (Hypericum perforatum L.) is a common plant in Bulgaria that is predominantly used in folk medicine to cure various disorders. Determining the chemical makeup of St. John’s wort inflorescences that were gathered from northern Bulgaria was the purpose of this investigation. The antioxidant activity of H. perforatum L. extracts was assessed using 1,1-diphenyl-2-picrilhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and Trolox equivalent antioxidant capacity (TEAC) tests on methanol extract. The amount of EO obtained by water distillation was 0.08%, with its main components (over 3%) being n-nonane (27.46%), β-sesquiphellandrene (11.17%), heptanal dimethyl acetal (5.94%), ethyl hexyl ketone (5.93%), undecane (3.75%), sabinene (3.3%), and tridecyl alcohol (3.1%). Methanol extracts were obtained from the inflorescences, with the total flavonoid content determined as 8.66 mg quercetin equivalents (QE)/mg and total phenolic content as 271.33 mg Gallic acid equivalent/g. The FRAP assay yielded 493.07 µmol/L of antioxidant activity, while the TEAC assay yielded 106.39 µmol/L, respectively. Our findings enable a comprehensive characterization of H. perforatum from Bulgaria and an assessment of its oil suitability for potential industrial applications. Additionally, the results could guide the selection of specimens for future targeted breeding efforts.

More than just a beer – Brewers' spent grain, spent hops, and spent yeast as potential functional fillers for polymer composites

Beer is among the most popular beverages in the world, with the production distributed uniformly between the biggest continents, so the utilization of brewing by-products is essential on a global scale. Among their potential recipients, the plastics industry offers extensive range of potential products. Herein, the presented study investigated the application of currently underutilized solid brewing by-products (brewers' spent grain, spent hops, spent yeast) as fillers for highly-filled poly(ε-caprolactone)-based composites, providing the first direct connection between spent hops or spent yeast and the polymer composites. Comprehensive by-product characterization revealed differences in chemical composition. The elemental C:O ratio, protein content, and Trolox equivalent antioxidant capacity varied from 1.40 to 1.89, 12.9 to 32.4 wt%, and 2.41 to 10.24 mg/g, respectively, which was mirrored in the composites' structure and performance. Morphological analysis pointed to the composition-driven hydrophilicity gap limiting interfacial adhesion for high shares of brewers' spent grain and spent hops, due to high hydrophilicity induced by carbohydrate content. Phytochemicals and other components of applied by-products stimulated composites' oxidative resistance, shifting oxidation onset temperature from 261 °C for matrix over 360 °C for high spent yeast shares. Simultaneously, spent yeast also provided compatibilizing effects for poly(ε-caprolactone)-based composites, reducing complex viscosity compared to other fillers and indicating its highest affinity to poly(ε-caprolactone)due to the lowest hydrophilicity gap. The presented results indicate that the proper selection of brewing by-products and adjustment of their shares creates an exciting possibility of engineering composites' structure and performance, which can be transferred to other polymers differing with hydrophilicity.

Antioxidant, Anti-Diabetic, and Anti-Inflammation Activity of Garcinia livingstonei Aqueous Leaf Extract: A Preliminary Study.

Diabetes mellitus (DM) is the second leading cause of mortality globally. The increased concern for DM is due to the underlying complications accompanying hyperglycaemia, associated with oxidative stress and consequent inflammation. The investigation of safe and effective treatments for DM is necessary. In the present study, the cytotoxicity, phytochemical analysis, antioxidant capacity, anti-inflammatory, and antidiabetic effects in an aqueous extract of Garcinia livingstonei leaves were assessed. All tested extract concentrations showed no toxicity against C3A hepatocytes. Several phenolic compounds were identified using ultra-high performance liquid chromatography mass spectrometry (UHPLC-MS). The total polyphenol content was 100.9741 mg GAE/g, 16.7712 mg CE/g flavanols, and 2.3548 mg QE/g flavonols. The antioxidant capacity values were 253.4268 mg AAE/g, 192.232 mg TE/g, and 167.8724 mg TE/g for ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), and 2,2-diphenyl-1-pycrylhydrazyl (DPPH), respectively. The plant extract significantly (p < 0.05) demonstrated anti-inflammatory and hypoglycaemic effects in a dose-dependent manner, with the α-glucosidase inhibition of the extract being higher (p < 0.05) than in the standard conventional drug (acarbose). The findings of this study revealed the potential of the constituents of G. livingstonei aqueous leaf extract in DM treatment. Further studies on the preparation and mechanisms of action of the plant in DM treatment are recommended.

Impact of Seminal Plasma Antioxidants on DNA Fragmentation and Lipid Peroxidation of Frozen-Thawed Horse Sperm.

Cryopreservation is a stressful process for sperm, as it is associated with an increased production of reactive oxygen species (ROS). Elevated ROS levels, which create an imbalance with antioxidant capacity, may result in membrane lipid peroxidation (LPO), protein damage and DNA fragmentation. This study aimed to determine whether the membrane LPO and DNA fragmentation of frozen-thawed horse sperm relies upon antioxidant activity, including enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) and paraoxonase type 1 (PON1)); non-enzymatic antioxidant capacity (Trolox-equivalent antioxidant capacity (TEAC), plasma ferric reducing antioxidant capacity (FRAP) and cupric reducing antioxidant capacity (CUPRAC)); and the oxidative stress index (OSI) of their seminal plasma (SP). Based on total motility and plasma membrane integrity (SYBR14+/PI-) after thawing, ejaculates were hierarchically (p < 0.001) clustered into two groups of good- (GFEs) and poor-(PFEs) freezability ejaculates. LPO and DNA fragmentation (global DNA breaks) were higher (p < 0.05) in the PFE group than in the GFE group, with LPO and DNA fragmentation (global DNA breaks) after thawing showing a positive relationship (p < 0.05) with SP OSI levels and ROS production. In addition, sperm motility and membrane integrity after thawing were negatively (p < 0.05) correlated with the activity levels of SP antioxidants (PON1 and TEAC). The present results indicate that LPO and DNA fragmentation in frozen-thawed horse sperm vary between ejaculates. These differences could result from variations in the activity of antioxidants (PON1 and TEAC) and the balance between the oxidant and antioxidant components present in the SP.

Colorimetric Sensing of Antioxidant Capacity via Auric Acid Reduction Coupled to ABTS Oxidation.

In this study, a simple and sensitive colorimetric assay has been developed for total antioxidant capacity measurement. The assay is based on the absorption measurement of the bluish-green oxidized product (ABTS·+) formed as a result of the oxidation reaction of the chromogenic reagent ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) with gold(III). However, in the presence of antioxidants, the ABTS oxidation process is effectively suppressed due to the reduction of gold(III) ions to the zerovalent state forming gold nanoparticles (AuNPs). Relatively lighter colors and a significant decrease in absorbance are observed depending on the total antioxidant capacity. Taking advantage of this situation, qualitative and quantitative total antioxidant capacity (TAC) measurements, with the naked eye and UV-vis spectroscopy, respectively, could be successfully performed. The assay is named "auric reducing antioxidant capacity" (AuRAC) because the gold(III) ion-reducing ability of antioxidants is measured. The AuRAC assay was applied to dietary polyphenols, vitamin C, thiol-type antioxidants, and their synthetic mixtures. Trolox equivalent antioxidant capacity (TEAC) values obtained with the AuRAC assay were found to be compatible with those of the reference CUPRAC (cupric reducing antioxidant capacity) assay. The AuRAC assay was validated through linearity, additivity, precision, and recovery, demonstrating that the assay is reliable and robust. Compared to the simple TAC assays in the literature based on AuNP formation with subsequent surface plasmon resonance (SPR) absorbance measurement, this indirect assay has a smoother linear range starting from lower antioxidant concentrations. This method displays much higher molar absorption coefficients for antioxidant compounds than other conventional single electron transfer (SET) assays because 3-e- reduction of trivalent gold (i.e., Au(III) → Au(0)) produces three chromophore cation radicals (ABTS·+) of the assay reagent. The sensor has been successfully applied to complex matrices, such as tea infusions and pharmaceutical samples. The AuRAC assay stands out with its high molar absorptivity connected to enhanced sensitivity as well as its potential to convert into a paper-based colorimetric sensor.

DPPH Measurements and Structure-Activity Relationship Studies on the Antioxidant Capacity of Phenols.

The consumption of foods that are high in antioxidant capacity is believed to contribute to good health. Moreover, the addition of highly antioxidant compounds to foods is believed to prevent food deterioration. Among the known antioxidants in food, phenols have been identified as the primary antioxidants. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay is a simple, inexpensive, and rapid method widely used to evaluate the antioxidant capacity. Although the results of the DPPH assay depend on conditions such as the reaction time and concentration, the experimental conditions have not been standardized. Further, previous research that compared the antioxidant capacity determined through the DPPH assay largely focused on the differences in the specific substructures of approximately several dozen compounds. In this study, we conducted DPPH assays on 169 phenols under the same experimental conditions and summarized the correlation between their structures and activity. This DPPH assay study is the first single-laboratory investigation of the largest number of components in terms of their Trolox equivalent antioxidant capacities. Further, the analysis method was reproduced in an interlaboratory collaborative study, enabling its application in the reproduction and comparison of measurements in other laboratories.

Quality and functional properties of bread containing the addition of probiotically fermented Cicer arietinum

This study aimed to determine the impact of supplementation with probiotically fermented chickpea (Cicer arietinum L) seeds on the quality parameters and functional characteristics of wheat bread. The addition of chickpea seeds caused significant changes in the chemical composition of the control wheat bread. The legume-supplemented products exhibited higher values of a* and b* color parameters and higher hardness after 24 h of storage than the control. The application of fermented or unfermented chickpeas contributed to an increase in total polyphenol and flavonoid contents, iron chelating capacity, and antioxidant properties of the final product. The variant containing unfermented seeds had the highest riboflavin content (29.53 ± 1.11 µg/100 g d.w.), Trolox equivalent antioxidant capacity (227.02 ± 7.29 µmol·L−1 TX/100 g d.w.), and free radical scavenging activity (71.37 ± 1.30 % DPPH inhibition). The results of this preliminary research have practical importance in the production of innovative bakery products with potential properties of functional food.

Antioxidant and angiotensin converting enzyme inhibitory activities of red lionfish (Pterois volitans L.) muscle protein hydrolysates obtained using pepsin-pancreatin system

Despite being an invasive species and representing a threat in the area, red lionfish (Pterois volitans L.) meat is valued for its pleasant taste and high protein content. The objective of the present work was to evaluate the angiotensin converting enzyme inhibition (ACE-I) and the antioxidant activities of red lionfish muscle protein hydrolysates in vitro. Hydrolysates were obtained using the pepsin-pancreatin system, and their degree of hydrolysis (DH), electrophoretic, and amino acid profile were determined. Subsequently, their ACE-I and ABTS+ radical scavenging activity were evaluated, selecting those with the highest response. The highest DH (66.1%) was found in the hydrolysate obtained at 120 min of reaction time (H120); electrophoresis revealed the action of the enzymes on the muscle proteins. The highest bioactivities occurred during hydrolysis with pepsin for 60 min (H60), obtaining the highest ACE-I of 68.8% (evaluated with 500 µg protein) with a DH of 16.8%, ACE-I related amino acid content of 33.6%, and hydrophobic amino acid content of 42.9%. With the 30 min hydrolysates (H30), the highest Trolox equivalent antioxidant capacity of 60.3 mM/mg protein was obtained with 18.4% DH and 22.1% radical scavenger amino acids; its comparison with H120 proved that higher DH did not produce a greater response in ABTS+ radical scavenging activity, DPPH, reducing power, and copper chelation assays; with β-carotene bleaching being the exception. Therefore, it can be concluded that red lionfish muscle hydrolysates could be a promising source of peptides with antihypertensive and antioxidant properties, and can be suitable as functional ingredients.