Measurement Of Antioxidant Capacity Research Articles

Bacterial Consortium Biofilm-Based Electrochemical Biosensor for Measurement of Antioxidant Polyphenolic Compounds

This work describes the development of an electrochemical biosensor method based on bacterial consortia to determine antioxidant capacity. The bacterial consortium used is a combination of bacteria from the genera Bacillus and Pseudomonas which can produce the enzymes tyrosinase and laccase. The consortium bacteria were immobilized on the surface of the screen-printed carbon electrode (SPCE) to form a biofilm. Biofilms were selected based on the highest current response evaluated electrochemically using cyclic voltammetry analysis techniques. Optimum consortium biofilm conditions were obtained in a phosphate buffer solution of pH 7, and biofilm formation occurred on day 7. This work produces analytical performance with a coefficient of determination (R2) of 0.9924. The limit of detection (LOD) and limit of quantification (LOQ) values are 0.5 µM and 10 µM, respectively. The biosensor showed a stable response until the 10th week. This biosensor was used to measure the antioxidant capacity of five extracts, and the results were confirmed using a standard method, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The highest antioxidant capacity is guava extract and the lowest is tempuyung extract. Thus, the development of this biosensor method can be used as an alternative for measuring antioxidant capacity.

EVALUATION OF ANTIOXIDANT ACTIVITY OF NOVEL ORGANOTIN COMPLEXES DERIVED FROM A NEWLY SYNTHESIZED LIGAND AND THEIR STRUCTURAL CHARACTERIZATION

In this work, of New Ligand [(E)-5-hydroxy-4-(3-(4-methoxy phenyl) acryl amido) naphthalene -1- sulfonic acid] (ANS) was prepared by reflexing reaction of 4-amino-5-hydroxy naphthalene sulfonic acid with para methoxy cinnamic acid, this produced and described chemical was employed as ligand to prepare tri and di-organotin complexes by condensation reaction with the salts of organotin chloride (phenyl, butyl, and methyl tin chloride). Specialized methods, including elemental analysis, (tin and proton) magnetic resonance, and infrared spectra, were used to identify the complexes. DPPH (2,2-diphenyl-1-picrylhydrazyl) and CUPRAC (Cupric Reducing Antioxidant Capacity) are both commonly used methods for measuring antioxidant capacity in various samples. Due to the tin moiety, the produced tri and di-tin complexes gave higher percentage inhibition than the ligand in both techniques; also, the triphenyltin complex performed the best when compared to the others. The results of this study are expected to contribute to the understanding of the structure-activity relationship of organotin complexes and their potential as antioxidants, which may have implications for developing novel therapeutic agents with antioxidant properties.

Oxidative state is associated with migration distance, but not traits linked to flight energetics

Flight can be highly energy demanding, but its efficiency depends largely on flight style, wing shape and wing loading, and a range of morphological and lifestyle adaptations that can modify the cost of sustained flight. Such behavioural and morphological adaptations can also influence the physiological costs associated with migration. For instance, during intense flight and catabolism of reserves, lipid damage induced by pro‐oxidants increases, and to keep oxidative physiological homeostasis under control, the antioxidant machinery can be upregulated. Studies on the oxidative physiology of endurance flight have produced contradictory results, making generalization difficult, especially because multispecies studies are missing. Therefore, to explore the oxidative cost of flight and migration, we used samples collected during the breeding season from 113 European bird species and explored the associations of measures of antioxidant capacity (total antioxidant status, uric acid and glutathione concentration) and oxidative damage of lipids (malondialdehyde) with variables reflecting flight energetics (year‐round or specifically during migration) using a phylogenetic framework. We found that none of the traits predicting year‐round flight energy expenditure (flight style, wing morphology and flight muscle morphology) explained any measures of oxidative state. Our results suggest that birds endure their everyday flight exercise without or with low oxidative cost. However, oxidative damage to lipids and one component of the endogenous antioxidant system (uric acid), measured after the end of spring migration on breeding adult birds, increased with migration distance. Our results suggest that migration could have oxidative consequences that might be carried over to subsequent life‐history stages (breeding).

When MnSiO3 meets ratiometric fluorescence: A facile, cost-effective ratiometric fluorescent platform based on oxidase-like MnSiO3 nanozyme for versatile Total Antioxidant Capacity (TAC) measurements

The level alterations of antioxidants are highly associated with various oxidative stress-related diseases, food quality and drug safety problems, which enables the reliable and accurate determination of total antioxidant capacity (TAC) become progressively significant. Herein, for the first time, we explored the catalytic effect of MnSiO3 nanozyme with oxidase-like activity towards different fluorescent substrates, and introduced ratiometric fluorescence to MnSiO3-based biosensing. By harnessing MnSiO3-propelled catalytic oxidation of two fluorescent substrates with contrary responses (Scopoletin, SC and o-phenylenediamine, OPD), we constructed a facile, cost-effective ratiometric fluorescent (RF) platform for TAC measurement. In the absence of antioxidants, SC and OPD can be oxidized, and the synergistic effect of fluorescence resonance energy transfer (FRET) and inner-filter-effect (IFE) between SC and oxidized OPD (Ox-OPD) will result in the weak fluorescence of Ox-SC at 465 nm and the strong one of Ox-OPD at 562 nm, respectively. However, the addition of antioxidants will dissociate MnSiO3, generating the recovered high/low fluorescence values of both substrates. Through monitoring the FI465/FI562 changes, the RF analysis of different antioxidants (Cys, AA, GSH) with satisfactory sensitivity is performed and the TAC measurements in diverse real samples (human serums, beverages, and drugs) are successfully accomplished. Moreover, the system demonstrates high selectivity and could compete with the commercial TAC test kits.

Macular Pigment Optical Density as a Measurable Modifiable Clinical Biomarker.

Carotenoids are present throughout retina and body its dense deposition leads to an identifiable yellow spot in the macula. Macular pigment optical density (MPOD) measured in the macula is vital to macular well-being and high-resolution visual acuity. MPOD has also been associated with various health and disease states. We sought to review the literature on this topic and summarize MPODs role as a measurable modifiable clinical biomarker, particularly as a measure of the eye's antioxidant capacity in the context of oxidative damage and retinal ischemia. A literature review collated the articles relevant to MPOD, carotenoid intake or supplementation, and their influence on various health and disease states. Literature reveals that MPOD can serve as a reliable biomarker for assessing the retinal defense mechanisms against oxidative stress and the deleterious effects of excessive light exposure. Elevated MPOD levels offer robust protection against the onset and progression of age-related macular degeneration (AMD), a prevalent cause of vision impairment among the elderly population. MPOD's implications in diverse ocular conditions, including diabetic retinopathy and glaucoma, have been explored, underscoring the real need for clinical measurement of MPOD. The integration of MPOD measurement into routine eye examinations presents an unparalleled opportunity for early disease detection, precise treatment planning, and longitudinal disease monitoring. Longitudinal investigations underscore the significance of MPOD in the context of age-related ocular diseases. These studies show promise and elucidate the dynamic nuances of MPOD's status and importance as a measurable, modifiable clinical biomarker.

Characterisation of wild red raspberry ecotypes in Northern Anatolia: Insights into sensory, biochemical and antioxidant properties

ABSTRACT Red raspberries are among the most significant wild edible fruits (WEFs) in Türkiye, thriving in cold to warm temperate regions across the country. This study focuses on 11 wild red raspberry ecotypes sampled from the Northern Anatolia region, examining their sensory, biochemical and antioxidant properties. Sensory analysis was used to compare ecotypes based on aroma, taste and juiciness. Biochemical assessments included soluble solid content (SSC), vitamin C amount, organic acids, total anthocyanins (TA), total phenolic content (TPC), total flavonoid content and total antioxidant capacity. The Ferric Reducing Antioxidant Power (FRAP) assay measured antioxidant capacity. Despite similar growing conditions, significant variations were observed among ecotypes and across years. In the first year, fruit weights ranged from 1.04 g to 1.33 g, and in the second year, they ranged from 0.97 g to 1.27 g. Fruit chroma values ranged between 26.11 and 33.70 in 2021, and 23.17 and 30.19 in 2022. Vitamin C exhibited considerable variability, ranging from 29.3 mg · 100 g−1 to 44.4 mg · 100 g−1 across ecotypes and years. TPC, total anthocyanin content (TAC) and total flavonoid content ranged from 164 mg to 390 mg gallic acid equivalent (GAE) · 100 g−1, 17.3 mg to 33.2 mg cyanidin-3-glucoside equivalent · 100 g−1 and 10.3 mg to 17.6 mg quercetin equivalent (QE) · 100 g−1, respectively, in both years. Citric acid emerged as the dominant organic acid across all ecotypes. Notably, the ecotypes V-4, V-8, V-3 and V-10 showcased larger, more appealing fruits suitable for fresh consumption, whereas V-3 and V-5 presented sweeter fruits ideal for processing. Additionally, the ecotypes V-6, V-7 and V-11 displayed higher levels of health-promoting compounds, such as TPC and antioxidant capacity, suggesting their potential as functional foods and valuable sources of natural antioxidants in the future.

Antidepressant potential of β-caryophyllene in maternal separation-induced depression-like in mice: A focus on oxidative stress and nitrite levels

BackgroundMajor depressive disorder is prevalent across different societies, affecting individuals from various cultural and socioeconomic backgrounds. Dysregulation of the nitric oxide (NO) pathway and increased oxidative stress have been implicated as contributing factors. PurposeThis study aimed to explore the antidepressant potential of β-caryophyllene in a mouse model subjected to maternal separation stress, with a focus on its effects on oxidative stress and nitrite levels. Study DesignThe research involved 40 male mice, which were divided into five groups. MethodsThe control group received 1 ml/kg of normal saline, while the maternal separation (MS) groups were administered normal saline in conjunction with β-caryophyllene at doses of 10, 20, and 50 mg/kg. Various behavioral tests, including the open field test (OFT), forced swimming test (FST), and splash test, were employed to assess the impact of β-caryophyllene. Additionally, measurements of total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrite levels in the hippocampus were conducted. ResultsThe findings demonstrated that maternal separation stress induced depressive-like behaviors in mice, as evidenced by increased immobility time in the FST and decreased grooming behavior in the splash test. Furthermore, MS was associated with elevated MDA and nitrite levels and reduced TAC in the hippocampus. However, administration of β-caryophyllene increased grooming activity in the splash test and decreased immobility time in the FST. Additionally, β-caryophyllene exhibited antioxidant properties, lowering MDA and nitrite levels while enhancing TAC in the hippocampus. ConclusionThese results suggest that β-caryophyllene may possess antidepressant-like effects in mice subjected to maternal separation, likely due to its antioxidant actions in the hippocampus.

High serum levels of reactive nitrogen species and low total antioxidant capacity in patients with resistant hypertension compared to those in age- gender matched healthy controls, controlled hypertension and follow up with propranolol treatment in the extended APPROPRIATE trial

ObjectivesTo perform a comparative analysis of the extended APPROPRIATE trial of measures of reactive nitrogen species and antioxidant capacity in patients having resistant hypertension with controlled hypertension and healthy controls.ResultsMean serum NO2- and NOx levels were significantly lower and mean AOC was significantly higher in patients with controlled hypertension (n = 38) and healthy controls (n = 38) compared to resistant hypertension (RHTN) patients (n = 40) at the pre-intervention stage (p < 0.001). The serum NO2-, NOx and AOC levels of both controlled hypertension and healthy controls were comparable to those of the RHTN patients following treatment with propranolol (n = 18). Considering all samples (n = 114) we noted that there were significant weak and moderate positive correlations between NO2− levels with systolic blood pressure (SBP) and diastolic blood pressure (DBP) (r = 0.396, p < 0.001 and r = 0.292, p = 0.004) as well as total NOx levels with SBP and DBP (r = 0.636 and r = 0.480 respectively, p < 0.001). Conversely, there was a significant negative correlation between AOC levels with SBP and DBP (r= -0.846 and r = -0.626 respectively, p < 0.001).

Dietary and serum antioxidant capacity is inversely associated with patients in osteoarthritis: a case-control study

This study aimed to examine dietary antioxidant and serum antioxidant capacity in patients with knee osteoarthritis (OA). This case-control study consisted of 47 patients with OA (case group) and 30 healthy subjects (control group). The control and case group were matched age, gender, and body mass index (p > 0.05). A food frequency questionnaire was administered to participants, and dietary total antioxidant capacity (DTAC) was estimated using the ferric reducing antioxidant power method (FRAP). Participants’ serum total antioxidant capacity (TAC) and total oxidant capacity (TOC) measurements were performed, and the oxidative stress index (OSI) was calculated. DTAC of case group was found to be lower than the control group (p < 0.05). The daily consumption of red meat and butter of the individuals in the case group was higher than that of the control group, and their fish consumption, dietary vitamin A and carotene intakes were found to be lower (p < 0.05). In addition, OA patients have TAC and OSI was also found to be significantly higher than in control group (p = 0.001 and p < 0.001). Since low dietary total antioxidant capacity and high serum total oxidant capacity, individuals with OA should pay more attention to their diet to increase serum antioxidant status.

Relation of Total Antioxidant Capacity to Clinical Severity of COVID-19 Infection in Paediatric Patients

Abstract Objectives The pathogenesis of COVID-19 infection is still not well clarified. In this regard oxidative stress and its relation to disease severity is one of the topics that need to be investigated. Aim This study was carried out to investigate the relationship between the oxidant stress and antioxidant system represented by total antioxidant capacity and clinical severity of COVID19 infection in pediatric age group. Methods The current cross-sectional study included 45 patients with COVID 19 PCR-proven infection admitted at the Children’s Hospital, Faculty of Medicine, Ain Shams University compared to 45 healthy age and sex matched control group. Detailed medical history, thorough examination and recording of all infection related laboratory parameters were done for each enrolled case. Measurement of total antioxidant capacity (TAC) in the serum of all studied patients and controls was done by ELISA. Results TAC levels were considerably lower in pediatric patients (median 24u/l, IQR 9-37u/l) compared to healthy individuals (median 90u/l, IQR 77-100u/l, p &amp;lt; 0.001) and the levels were statistically lower in severe cases compared to those with mild disease (p = 0.008). In this regard, 100% of controls showed normal TAC while only 31.1% from cases exhibited normal TAC levels and 68.9% of cases had low TAC levels. There was strong statistical significance between PICU admission and low TAC levels (p = 0.035). Additionally, the TAC showed negative correlation with the initial CRP of patients (r= -0.433, p = 0.003). There was also a significant inverse correlation between TAC and time needed for viral clearance (r=- 0.418, p = 0.004) as well as a significant positive correlation between body mass index z-score and TAC levels (r = 0.423, p value 0.004). Conclusion Total antioxidant capacity could serve as a novel prognostic marker of COVID -19 infection severity in pediatric patients.

Optimization of polysaccharide conditions and analysis of antioxidant capacity in the co-culture of Sanghuangporus vaninii and Pleurotus sapidus

Fungal polysaccharides are commonly utilized in the food industry and biomedical fields as a natural and safe immune modulator. Co-culturing is a valuable method for enhancing the production of secondary metabolites. This study used intracellular polysaccharide (IPS) content as a screening index, co-culturing seven different fungi with Sanghuangporus vaninii. The seed pre-culture liquid culture time was selected through screening, and conditions were assessed using single factor experimentation, a Plackett-Burman (PB) design, and response surface methodology (RSM) optimization. RSM optimization was conducted, leading to the measurement of antioxidant capacity. Results indicated that the co-culture of S. vaninii and Pleurotus sapidus exhibited the most effective outcome. Specifically, pre-culturing S. vaninii and P. sapidus seed cultures for 2 days and 0 days, respectively, followed by co-culturing, significantly increased IPS content compared to single-strain culturing. Further optimization of co-culture conditions revealed that yeast extract concentration, liquid volume, and S. vaninii inoculum ratio notably influenced IPS content in the order of yeast extract concentration &gt; liquid volume &gt; S. vaninii inoculum ratio. Under the optimal conditions, IPS content reached 69.9626 mg/g, a 17.04% increase from pre-optimization co-culture conditions. Antioxidant capacity testing demonstrated that co-cultured IPS exhibited greater scavenging abilities for DPPH and ABTS free radicals compared to single strain cultures. These findings highlight the potential of co-culturing S. vaninii and P. sapidus to enhance IPS content and improve antioxidant capacity, presenting an effective strategy for increasing fungal polysaccharide production.

Phenolic, Flavonoid Contents, Antioxidant, and Antibacterial Activity of Selected Eucalyptus Species: Review

Many medicinal plants and their essential oils are used to treat or prevent diseases without the risk of mutagenicity, carcinogenicity, or teratogenicity. Eucalyptus essential oils are commonly used as preservatives, flavoring agents, and various consumer goods. Eucalyptus leaves are being widely studied due to their volatile essential oils, including 1,8-cineole, p-cymene, α- and β-pinene, limonene, citronellal, citral, eudesmol, terpinen-4-ol, terpineol, α–phellanderene, and 9β-sitosterol. Among these compounds, 1,8-cineole is the most abundant. Eucalyptus leaves are rich in flavonoids and phenolic compounds and are thus a great source of antioxidants. 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays were used to measure antioxidant capacity. The antioxidant activity of Eucalyptus essential oil is stronger than that of standard antibiotics such as erythromycin, cefixime, and gentamicin due to the presence of significant terpenoids in addition to phenolic chemicals and flavonoids. A lower IC50 indicates greater antioxidant potential. Phenolic compounds and flavonoids are often associated with beneficial health outcomes, including anti-inflammatory and antioxidant effects, anticancer properties, reduced risk of cardiovascular diseases, prevention of age-related neurodegenerative diseases, and prevention of Alzheimer’s disease. Flavonoids also play essential roles in plants, including protecting against reduction, fertility, reproduction, and infection. Due to their anti-inflammatory, antioxidative, and immunomodulatory properties, flavonoids are crucial for pharmacological, medical, and nutraceutical applications.

Renal Oxidative Stress May Explain Sex Differences in Blood Pressure in Adult Offspring Exposed to an Impoverished Environment

Background: Nearly 40 million people experience poverty in the United States. Poverty is linked to adverse childhood experiences (ACEs) which affects about 64% of adults in the U.S. Previous studies indicate that those who experience ACEs are at a higher risk of developing hypertension (HTN) and cardiovascular diseases (CVDs) later in life, with a greater severity and earlier onset in males. The mechanisms behind the ACEs-attributed development of sex differences in HTN later in life is unknown. One plausible mechanism for this sex difference is increased oxidative stress. One rodent model to mimic poverty as an ACE is the limited bed and nesting (LBN) model. This model simulates an impoverished and low resource environment, as observed in poverty, in which the nesting material during weaning is reduced. We hypothesize that male offspring exposed to LBN will have elevated blood pressure and oxidative stress, while females will have no change in blood pressure and reduced oxidative stress. Methods: Pregnant Sprague Dawley rats gave birth naturally and weaned their offspring for 3 weeks. During the weaning period, on Days 2-9, the dams and their respective pups were divided into 2 groups: LBN and control (CON). After LBN treatment, all rats received normal bedding. After weaning, offspring were divided by sex and experimental status: LBN male (n=5), LBN female (n=5), CON male (n=6), and CON female (n=6). At 16-17 weeks, mean arterial pressure (MAP) was measured via carotid catheterization and the kidneys, brain, heart, and plasma were collected to measure antioxidant capacity via colorimetric biochemical assays. Results: LBN males had a significant increase (18 mmHg) in MAP compared to CON males (128.17±3.93 vs 110.72± 3.93 mmHg, P&gt;0.001), while female LBN and CON rodents displayed no differences. In males, there were no changes in antioxidant capacity in the brain, heart, and plasma. However, there was a significant 2-fold decrease in renal antioxidant capacity (233±14.0 vs 442±12.3 mM Trolox/mg protein, p&gt;0.0001). In females, there were no changes in the kidneys, heart, and brain antioxidant capacity. Conversely, LBN females showed a trending increase in plasma antioxidant capacity compared to CON (3.33±0.16 vs 2.53±0.35 mM Trolox/mg protein, p=0.053). Conclusion: Only males exposed to an impoverished environment during weaning have elevated blood pressure, while females do not. This difference in blood pressure may be explained by decreases in renal antioxidant capacity in males only. On the other hand, females may be protected from elevated blood pressure because they experience a slight increase in systemic antioxidant capacity. Future studies will examine the role of antioxidants in blood pressure regulation in the kidneys. This study is clinically relevant because ACEs affect a large percentage of the American population with about 17% of adults experiencing 4 or more ACEs, with minorities at a greater risk. Understanding the mechanisms on how ACEs contribute to HTN may alleviate some of the racial and ethnic disparities, along with the financial burden on the healthcare system to care for people with HTN and CVDs. Perhaps, organ and sex-specific antioxidant therapies may be used to alter, prevent, or reduce the development of HTN in adults that were exposed to ACEs, such as poverty during nursing and early childhood. This research was supported by start-up funds and the American Heart Association Early Career Development Award [AHA 18CDA34110264 (Cunningham)]. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

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.

Evaluation of the content of polyphenols, flavonoids and tannins, the antioxidant capacity, and the antimicrobial activity of different organic and aqueous fractions of stems of Retama monosperma

Retama monosperma is an endemic plant of the Mediterranean region that has been traditionally used in folk medicine to treat various ailments. It contains a variety of bioactive phytochemicals and exhibited several biological activities. This study aimed to assess the phytochemical screening, total phenolic, total flavonoid, and total tannin compounds, as well as the antioxidant capacity and antimicrobial activity. The phytochemical screening involved color reactions, characteristic reagents, and precipitation methods. Total phenolic, flavonoid, and tannin compounds were quantified using colorimetric methods across four fractions. Antioxidant capacity was assessed using 2,2-Diphenyl-1-picrylhydrazyl radical scavenging, ferric reducing antioxidant power, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging, and phosphomolebdenum assay. The antimicrobial activity was evaluated through disc diffusion method and the microdilution assay. Qualitative phytochemical tests revealed the presence of flavonoids, tannins, terpenoids, alkaloids, and sterols. Quantification of total phenolic, flavonoid, and tannin compounds confirmed the richness of polyphenolic compounds in all fractions. The antioxidant capacity measurements revealed that the ethanol fractions exhibited the highest antioxidant capacity in 2,2-Diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power assays, and phosphomolebdenum assay. Conversely, the aqueous fraction showed highest activity in the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay. Regarding antimicrobial activity, the ethyl acetate fraction demonstrated superior efficacy against Staphylococcus aureus, and Bacillus cereus. These findings suggest that R. monosperma could serve as a valuable source of antioxidant and anti-infective phytocompounds.

Assessing the impact of body composition, metabolic and oxidative stress parameters on insulin resistance as a prognostic marker for reactive hypoglycemia: a cross-sectional study in overweight, obese, and normal weight individuals.

Oxidative stress (OS) plays a pivotal role in the pathogenesis of insulin resistance (IR), particularly in its association with obesity. This study evaluate both the diagnostic and clinical significance of assessing oxidative status in patients affected by overweight and obesity displaying IR, especially with reactive hypoglycemic episodes (RH). A comprehensive examination of OS biomarkers was carried out, encompassing measurements of total oxidative capacity (TOC) and total antioxidant capacity (TAC). Our analysis results reveal noteworthy connections between OS levels and the severity of IR in overweight and obese patients. Moreover, in the study, we demonstrated the diagnostic utility of serum concentrations of TAC and TOC as indicators of the risk of RH, the occurrence of which, even at the stage of overweight, may be associated with increased OS and further development of obesity. Our findings imply that the evaluation of oxidative status could serve as a crucial diagnostic and prognostic tool for patients observed with IR and overweight and obesity. In conclusion, our study underscores the potential utility of assessing oxidative status in the context of IR and highlights the possibility of identifying novel therapeutic targets for the treatment of overweight and obese patients.

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.

Evaluating oxidative stress biomarkers in oncology nurses exposed to antineoplastic drugs: A cross-sectional study

PurposeAntineoplastic drugs (ADs) are widely used in cancer treatment. Nurses in chemotherapy centers are exposed to these drugs during preparation. They can affect healthy cells, leading to teratogenic and mutagenic effects, as well as oxidative stress. This study aimed to evaluate oxidative stress biomarkers in the nurses exposed to these drugs. MethodThis study was conducted on 30 nurses exposed to ADs and 30 nurses with no exposure to these drugs as non-exposed group. Oxidative stress biomarkers were measured in the blood serum samples of both groups, including malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), total antioxidant capacity (TAC), and blood thiol groups. ResultsConsidering the possibility of confounding effect of nutritional supplement consumption, the effect of this factor was adjusted in the analysis. A significant difference was observed for CAT, SOD, thiol, and TAC biomarkers between two groups (P < 0.05). However, the difference in MDA and GPx biomarkers between two groups was not statistically significant. ConclusionsThe findings of the present study showed that supplement consumption has a significant effect on the biomarker of total antioxidant capacity. Thus, total antioxidant capacity measurement is advised as the best biomarker for tracking oxidative status in nurses exposed to ADs due to its capacity to measure all antioxidants in the body, except the thiol group, and its lower cost when compared to other biomarkers. Furthermore, it can be claimed that the consumption of nutritional supplements has a greater effect on the non-enzymatic biomarkers of oxidative stress than on enzymatic antioxidant system.

A preliminary study on a new approach for measurement of the antioxidant capacity of single molecules in food

Antioxidant activity refers to the rate of reaction between a specific antioxidant and a specific oxidant. On the other hand, antioxidant capacity is a measure of the quantity of a free radical in a concentration, neutralized by antioxidant molecules under examination. All common methods such as: Ferric Reducing Antioxidant Power (FRAP), Total Peroxyl Radical Antioxidant Parameter (TRAP), Oxygen Radical Absorption Capacity (ORAC), Crocin Bleaching Assay (CBA), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and others have some technical limitations. All methods, before any analytical test, require a sample preparation, which is separated into hydrophilic and lipophilic fractions. However, this already represents an artifact, because some of the properties of the biological matrix are lost. The new OXEFIN unit defined as the ratio between the electrical power of the sample and the control allows us to compare the antioxidant capacities of single substances or a mixture of them, without the use of a target molecule and equipment such as a spectrophotometer or other optical detection instruments. Moreover, we are able to detect the total antioxidant capacity in an opaque solution without sample preparation(such as food). The milks range from 2.73 ± 0.02 to 0.20 ± 0.003 at 4 ml and 4.33 ± 0.04 to 0.26 ± 0.003 at 8 ml. The berries and fruit juices range from 5350 ± 38 to 673 ± 5.8 at 4 ml and from 5220 ± 40 to 915 ± 5 at 8 ml. The method proposed in this paper represents a new approach to the antioxidant capacity measurements reducing the cost, analysis time, the amount of reagents and avoid the possible chemical interferences during the radical chain reaction.

Chemical properties, antioxidant, and antimicrobial activities of fruit extracts of Crataegus monogyna var. odemisii

Fruit of the Crataegus species (Rosaceae), known as the “Hawthorn” wild plant, has important benefits for human health. The purpose of this study was to determine the chemical properties of one of the local endemic taxa, Crataegus monogyna var. odemisii in west Turkey. Based on the chemical analysis results, antioxidant and antimicrobial activities of fruit extracts, the fruit lipid contents, total phenol, and total flavonoid contents were studied. Five different methods were used to measure antioxidant capacity, namely the CUPRAC, β-Carotene-linoleic acid, DPPH•, ABTS•+, and CUPRAC analyses were used for the measurement of antioxidant capacity. The results showed that the highest antimicrobial activity was against C. albicans, and it was more effective against Gr+ bacteria than Gr- bacteria. The qualitative, as well as quantitative, analyses of lipid contents of the fruits of C. monogyna var. odemisii were made by gas chromatographic analysis. Folin-Ciocalteu reagent was used for determining the total phenolic content, and aluminum chloride was used for determining the flavonoid content. Results revealed that there was a statistically significant relationship between the antioxidant activities and the phenolic and flavonoid contents in the extracts of Hawthorn fruits.