Antioxidant Capacity Profile Research Articles

Metabolite Profile and Antioxidant Capacity of Centella asiatica Leaves Extract with Different Extraction Methods

Centella asiatica known as pegagan in Indonesia, belongs to the Apiaceae family and is widely used as salad, cosmetics ingredients, and herbal medicine for improving memory. This research aimed to determine the total phenolics content (TPC), antioxidant capacity (AC), and FTIR spectrum of C. asiatica leaves extracts using different extraction methods. C. asiatica extracts were prepared using maceration, reflux, and ultrasonication. The Folin-Ciocalteu method was used to determine TPC, and we found a higher level of TPC when using maceration, about 9,96 ± 0,20 mg GAE g-1 dry powder. Antioxidant capacity from the three extracts was measured using DPPH and FRAP methods. The highest antioxidant capacity using DPPH and FRAP methods was found in C. asiatica leaves extract using maceration with a value of 29,60 ± 0,71 and 14,04 ± 0,38 𝜇mol TE g-1 dry powder, respectively. The FTIR spectrum of each extract indicates the presence of vibration from several functional groups such as O-H, C-H, and C=C, likely from phenolics and C-O. The pattern of FTIR spectrum from the three C. asiatica leaves extracts gives different spectrum profiles and characteristics. Principal component analysis using FTIR spectrum data shows good clustering for each extract with 89% data variability (PC1 77% and PC2 12%). It can be concluded that TPC, AC, and FTIR spectrum profiles are different when using different extraction methods.

The effect of alpha-lipoic acid supplementation on anthropometric, glycemic, lipid, oxidative stress, and hormonal parameters in individuals with polycystic ovary syndrome: a systematic review and meta-analysis of randomized clinical trials.

This systematic review and meta-analysis aimed to examine the effect of the antioxidant alpha-lipoic acid (ALA) on various cardiometabolic risk factors and hormonal parameters in patients with polycystic ovary syndrome (PCOS). We searched PubMed, EMBASE, SCOPUS, Cochrane Library, and Web of Science databases without language restrictions until May 2023 to find randomized controlled trials (RCTs) that assessed the impact of ALA supplementation on anthropometric, glycemic, lipid, oxidative stress, and hormonal parameters in women with PCOS. Outcomes were summarized using the standardized mean difference (SMD) and 95% confidence interval (CI) in a random-effects model. An I2 statistic of >60% established significant between-study heterogeneity. The overall certainty of the evidence for each outcome was determined using the grading of recommendations, assessment, development, and evaluations system. Seven RCTs met the inclusion criteria. The ALA group had significant reductions in fasting blood sugar (fasting blood sugar (FBS), n=7 RCTs, SMD, -0.60; 95% CI, -1.10 to -0.10; I2=63.54%, moderate certainty of evidence) and homeostatic model assessment for insulin resistance (homeostatic model assessment of insulin resistance (HOMA-IR), n=4 RCTs, SMD, -2.03; 95% CI, -3.85 to -0.20; I2=96.32%, low certainty of evidence) compared with the control group. However, significant differences were observed between the groups in body mass index, insulin, estrogen, follicle-stimulating hormone, luteinizing hormone, testosterone, low-density lipoprotein, highdensity lipoprotein, triglyceride, total cholesterol, malondialdehyde, or total antioxidant capacity profiles. ALA supplementation improves FBS and HOMA-IR levels in women with PCOS. ALA consumption is an effective complementary therapy for the management of women with PCOS.

Macronutrient, immunoglobulin a and total antioxidant capacity profiles of human milk from 1 to 24\u2009months: a cross-sectional study in Thailand

BackgroundAn extended duration of breastfeeding of up to two years is encouraged by many health authorities, but information regarding the composition of milk after one year postpartum is limited. The goal of this study was to determine the association between the duration of lactation and macronutrient contents, immunoglobulin A (IgA) levels and total antioxidant capacity (TAC) in human milk (HM), from 1 to 24 months postpartum.MethodsCross-sectional milk samples were collected between January and April 2019 from mothers with healthy full-term children who had been lactating for 1 to 24 months. The HM was biochemically analyzed for protein and carbohydrate contents by colorimetric assays. The fat content was determined by capillary centrifugation, and the energy content was calculated from the results of centrifugation assays. IgA levels and TAC were determined by ELISA and a Trolox equivalent antioxidant capacity (TEAC) assay, respectively. Pearson’s correlation coefficient and Spearman’s rank correlation coefficient were used to determine associations between months of lactation and milk composition, and multiple regression analysis was used to assess associations between months of lactation and milk composition adjusted for relevant covariates. Differences were considered significant at p < 0.05.ResultsOne hundred eighty-four milk samples were analyzed. The month of lactation was positively associated with the fat concentration (B = 0.31, SE = 0.09, p = 0.001), energy content (B = 3.11, SE = 0.92, p = 0.001), and IgA (B = 4.17, SE = 1.08, p < 0.001) but negatively associated with the carbohydrate concentration (B = − 0.22, SE = 0.01, p = 0.04). No association was observed between the month of lactation and the protein concentration or TAC after adjustment for maternal age, maternal BMI, birth order, and breastfeeding frequency.ConclusionThe duration of lactation was found to be positively associated with the fat, energy, and IgA content in HM for up to two years postpartum, and negatively associated with carbohydrate concentration. More prospective cohort studies are needed to obtain evidence-based knowledge regarding the changes in HM composition throughout the course of lactation.

Phytoestrogen coumestrol: Antioxidant capacity and its loading in albumin nanoparticles

Coumestrol is a polyphenol with promising therapeutic applications as phytoestrogen, antioxidant and potential cancer chemoprevention agent. The presence of two hydroxyl groups on its chemical structure, with orientation analogous to estradiol, is responsible of both, its antioxidant capacity and its estrogenic activity. However, several studies show that the interaction of polyphenols with food and plasma proteins reduces their antioxidant efficacy.We studied the interaction of coumestrol with bovine serum albumin protein (BSA) by fluorescence spectroscopy and circular dichroism techniques, and the effect of this interaction on its antioxidant activity as a hydroxyl radical scavenger. In addition, coumestrol antioxidant capacity profile using different assays (DPPH, ORAC-FL and ORAC-EPR) was studied. To explain its reactivity we used several methodologies, including DFT calculations, to define its antioxidant mechanism.Coumestrol antioxidant activity unveiled interesting antioxidant properties. BSA interaction with coumestrol reduces significantly photolytic degradation in several media thus preserving its antioxidant properties. Results suggest no significant changes in BSA structure and activity when interacting with coumestrol. Furthermore, this interaction is stronger than for other phytoestrogens such as daidzein and genistein.Considering our promising results, we reported for the first time the fabrication and characterization of coumestrol-loaded albumin nanoparticles. The resulting spherical and homogeneous nanoparticles showed a diameter close to 96 nm. The coumestrol incorporation efficiency in BSA NPs was 22.4%, which is equivalent to 3 molecules of coumestrol for every 10 molecules of BSA.

Maqui (Aristotelia chilensis (Mol.) Stuntz) and murta (Ugni molinae Turcz): Native Chilean sources of polyphenol compounds.

In recent years, the production, processing and exportation of maqui and murta Chilean berries have increased due to their high Total Polyphenols Content (TPC) and high Antioxidant Capacity (AC). However, the leaves of these berries are agroindustrial discards that present even higher TPC and AC values. Extracts of leaves and berries of maqui and murta with water, methanol and ethanol as solvents showed significant bioactivity, like inhibition of alpha-glucosidase (an enzyme involved in the metabolism of carbohydrates), as well as anti-inflammatory and antidiabetic effects. They are also excellent sources of polyphenols such as oligomers and polymers of delphinidin, pelargonidin, resveratrol, among others that have shown health-promoting bioactivity and good bioavailability. Purified extracts may be useful as supplements for foods and cosmetics, and even as pharmaceutical products. However, it is necessary to control the variability of their TPC, AC and polyphenols profiles caused by genotype, environment, processing, storage and stage of harvesting.

Chemical characterization and functional properties of selected leafy vegetables for innovative mixed salads

The content of bioactive compounds and antioxidant capacity of nine vegetables of conventional and unconventional utilization in salad mixtures were studied. The total phenolic and flavonoid contents ranged between 39.6–148.5 mg GAE/100g FW and 76.3–217.4 mg QE/100g FW, respectively. Ascorbic acid content ranged between 16.4 and 198.8 mg AAE/100g FW. Antioxidant capacity was assessed using DPPH, FRAP, and ORAC methods; values were in the range of 48.9–245.8 mg TE/100g FW, 67.7–335.8 mg TE/100g FW, and 104.86–833.9 mg TE/100g FW, respectively. Red cabbage, beet greens, parsley, and rocket exhibited the highest antioxidant capacities. Catechin was the most abundant phenolic compound identified in the free fraction, and p-coumaric acid, quercetin, and caffeic acid in the hydrolyzed fraction. Results suggested that the presence of these phenolics could be of great importance in preventing some chronic and degenerative diseases when regularly consumed. Nonconventional vegetables showed high antioxidant properties, therefore, it is important to promote their consumption. Practical applications Not all vegetables have the same phenolic composition, and not all phenolics have the same antioxidant capacity. Knowledge of the bioactive content and antioxidant capacity profile in each vegetable could be of interest to consumers and the food industry for selecting the more suitable leaves to make salad mixtures with high nutritional and functional values. These compounds can prevent some chronic-degenerative diseases related to oxidative stress, so it is important introduce them regularly into the diet. Moreover, the evaluation of nontraditional vegetables is intended to bring consumers toward a new source of bioactive compounds, prompting their consumption, and providing added value to certain plant parts that are sometimes considered as waste products.

Histologic chorioamnionitis does not modulate the oxidative stress and antioxidant status in pregnancies complicated by spontaneous preterm delivery

BackgroundInfection induced-inflammation and other risk factors for spontaneous preterm birth (PTB) and preterm premature rupture of membranes (pPROM) may cause a redox imbalance, increasing the release of free radicals and consuming antioxidant defenses. Oxidative stress, in turn, can initiate intracellular signaling cascades that increase the production of pro-inflammatory mediators.The objective of this study was to evaluate the oxidative damage to proteins and antioxidant capacity profiles in amniochorion membranes from preterm birth (PTB) and preterm premature rupture of membranes (pPROM) and to determine the role of histologic chorioamnionitis in this scenario.MethodsWe included 27 pregnant women with PTB, 27 pPROM and 30 at term. Protein oxidative damage was assayed by 3-nitrotyrosine (3-NT) and carbonyl levels, using enzyme-linked immunosorbent assay (ELISA) and modified dinitrophenylhydrazine assay (DNPH), respectively. Total antioxidant capacity (TAC) was measured by ELISA.ResultsProtein oxidative damage determined by carbonyl levels was lower in PTB group than pPROM and term groups (p < 0.001). PTB group presented higher TAC compared with pPROM and term groups (p = 0.002). Histologic chorioamnionitis did not change either protein oxidative damage or TAC regardless of gestational outcome.ConclusionThese results corroborates previous reports that pPROM and term birth exhibit similarities in oxidative stress- induced senescence and histologic chorioamnionitis does not modulate oxidative stress or antioxidant status.

Relation between polyphenol profile and antioxidant capacity of different Argentinean wheat varieties. A Boosted Regression Trees study

We report the polyphenol profile and antioxidant capacity (AC) of 12 Argentinean wheat varieties from different regions. The polyphenol profile was studied by HPLC–MS. The AC was measured by TEAC and FRAP. Twenty-five polyphenols were identified. ACA 315 and KLEIN GUERRERO varieties showed the highest content of polyphenols, whereas BIOINTA 3004, KLEIN CAPRICORNIO and LE 2330 showed the lowest one. ACA 315 presented the highest AC, while BIOINTA 3004 and KLEIN CAPRICORNIO showed the lowest one. Boosted Regression Trees (BRT) analyses helped finding significant correlations between AC and polyphenol profile, being hydroxybenzoic acid diglucoside, tryptophan, chrysoeriol-6,8-di-C-pentoside and isomers 4, 5, 9 and 12 of diferulic acids key compounds to explain the observed AC. To our knowledge, this is the first report on the interaction between the environment and wheat genotypes evaluated by BRT, showing how the whole polyphenol profile can explain the AC in wheat.

Estimated Glomerular Filtration Rate and Associated Clinical and Biochemical Characteristics in Type 2 Diabetes Patients

Background: Improved check on cardiovascular mortality due to diabetes has fast increased life span and prevalence of nephropathy in diabetics world over. Its variegated insidious sequel requiring useful markers for timely detection and address. Professional dictat is for periodic monitoring of estimated glomerular filtration rate (eGFR) in the diabetes patients. An indication of nephropathy from overall routine clinical and laboratory findings is worthwhile too. Objective: Study of clinico-demographic and biochemical indices associated with diabetic nephropathy defined by cutoff decline in eGFR, was undertaken to generate local evidence base for practice guidance. Method: 136 patients of type 2 diabetes mellitus under treatment at medicine outdoor for at least past one year were classified by eGFR cutoff of 60ml/min/1.73m 2 in to renal impaired (chronic kidney disease CKD group) and unimpaired groups. In a cross sectional study their clinico-demographic characteristics and biochemical investigation profiles were analysed and compared to elucidate local clinical evidence on relevant markers of CKD in type 2 diabetes. Result and Conclusion: Central obesity, long standing disease, inadequate glycaemic control, macroproteinuria, lower HDL-cholesterol and lower plasma antioxidant capacity profiles prominently associated diabetic patients with CKD. Hypertension was not prominently associated. Weight reduction, antioxidant nutrient supplements, better glycaemic control and improvement of HDL-cholesterol profiles were apparently demanding greater attention and care toward abetting/retarding occurrence of nephropathy in type 2 diabetes patients.

Valorization of grape pomace: Extraction of bioactive phenolics with antioxidant properties

Grape pomace can be regarded as an excellent and affordable source of polyphenolic compounds. Hence, the main objective of this work was to conduct a comparative study of different Portuguese grape varieties, using an extraction methodology with possible applications in sustainable agriculture and pest management. Scavenging capacity against DPPH, oxygen radical absorbance capacity (ORAC), iron(II) chelating ability (ICA) and Folin–Ciocalteu assays were performed in order to evaluate the antioxidant capacity profile and total phenolic content (TPC) in ethanol/water extracts and aqueous grape pomace suspensions. Strong significant correlation between TPC and DPPH (R=0.944), and a low correlation between ORAC and the other assays was obtained (R≤0.632). ICA was not correlated with any of the other assays (R≤0.263). All grape pomace extracts have presented high antioxidant properties (ORAC) and chelating ability, ranging from 906 to 2337μmol TEg−1 residue and from 55 to 104 % inhib. mg−1 residue, respectively. Results from HPLC analysis showed the presence of gallic acid, caffeic acid, syringic acid, (+)-catechin and (−)-epicatechin being syringic acid and (+)-catechin the major compounds. Although further studies are required, “Touriga Nacional” was the most promising grape cultivar regarding its highest values for TPC (142.4±1.1mg GAEg−1 dry residue), DPPH (1.12±0.04 mmol TEg−1 dry residue) and ORAC (1579±244μmol TEg−1 dry residue) assays. Since Portugal is a major wine producer, utilization of pomace generated during the wine elaboration steps opens a new trend toward a simple and relatively easy compounds extraction with high antioxidant activity in order to contribute to emerging industrial applications and sustainable agriculture.

Antioxidant capacity and phenolic content of commonly used anti-inflammatory medicinal plants in Colombia

Oxidative stress is a major factor related to the development of inflammatory diseases, which have traditionally been treated with medicinal plants. Given this relationship, into the research of natural antioxidant sources, the antioxidant capacity profiles of 11 species used in traditional medicine as anti-inflammatories were determined. The antioxidant capacity profile was investigated by using different methodologies that consider electron transfer mechanisms (ET), such as stabilization of the DPPH radical, ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), and hydrogen atom transfer mechanisms (HAT) such as oxygen radical absorption capacity (ORAC) and the inhibition of lipid peroxidation of lipoproteins through the assessment of conjugated dienes and thiobarbituric acid reactive substances (TBARS). Additionally, the total polyphenol content by the Folin–Ciocalteu method was determined, and the correlation between antioxidant capacity and polyphenol content was estimated. The best amounts of total phenolics and maximum values found in DPPH, FRAP, TEAC, and inhibition of lipid oxidation tests were for extracts of Tibouchina kingii, Pseudelephantopus spiralis, and Mimosa albida. Correlation between polyphenol content with ET tests was observed (r2>0.85, p<0.001), explaining more than 72% of the antioxidant capacity of the extracts. Additionally, a highly significant correlation was observed between the ORAC and the TBARS tests, confirming that the antioxidant capacity is due in part to transfer mechanisms involving hydrogen atoms. These findings may confirm the interesting potential of these plants as a valuable source of natural bioactive molecules.

Influence of peptides–phenolics interaction on the antioxidant profile of protein hydrolysates from Brassica napus

The role of the peptides–phenolic compounds (PC) interaction on the antioxidant capacity profile (ACP) of protein hydrolysates from rapeseed (Brassica napus) was studied in 36 hydrolysates obtained from a PC-rich and PC-reduced protein substrate. The latent profile analysis (LPA), with data of seven in vitro methods and one assay for cellular antioxidant activity (CAA), allowed identifying five distinctive groups of hydrolysates, each one with distinctive ACP. The interaction of peptides with naturally present PC diminished in vitro antioxidant activity in comparison with their PC-reduced counterparts. However, CAA increased when peptides–PC interaction occurred. The profile with the highest average CAA (62.41±1.48%), shown by hydrolysates obtained by using alcalase, shared typical values of Cu2+-catalysed β-carotene oxidation (62.41±0.43%), β-carotene bleaching inhibition (91.75±0.22%) and Cu2+-chelating activity (74.53±0.58%). The possibilities for a sample to exhibit ACP with higher CAA increased with each unit of positively charged amino acids, according to multinomial logistic regression analysis.

Determination of Phytochemicals and Antioxidant Activity in Butterhead Lettuce Related to Leaf Age and Position

The effect of leaf position on phytochemical distribution in butterhead lettuce was assessed by rings (from ring 1: outer leaves, to ring 6: inner leaves) or by zones (external, middle, internal). Maximum ascorbic acid was found in middle rings while chlorophyll and carotenoids gradually decreased from external to internal rings. Outermost leaves accumulate more phenolics and present more antioxidant activity as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and trolox-equivalent antioxidant capacity methods. However, the presence of phenolics in this zone also contributes to the enzymatic browning. Quantitative but not qualitative differences were found in the phenolic profiles between inner and outer lettuce zones. The major phenolic compounds identified were the phenolic acids chicoric, chlorogenic and isochlorogenic. For all phenolic compounds, greater content was always found in the external zone except for caffeic acid. A high correlation between DPPH and total phenolics, chlorophyll and carotenes indicated that these compounds were major contributors of antioxidant activity in lettuce. Practical Application During lettuce development, each leaf had a different level of exposure to environmental conditions (light, humidity, nutrients absorption and temperature) and also inner leaves are younger than outer ones. These factors may affect the distribution of phytochemicals and antioxidant capacity in the lettuce head. Knowledge of the bioactive content and antioxidant capacity profile in lettuce plants could be of interest to consumers and the food industry for selecting the more suitable leaves to make salads or other ready-to-eat mixed vegetable dishes with high nutritional value. Additionally this study reveals, from a nutritional point of view, the losses value of regular greengrocers' practices that include the removal of the external lettuce leaves as storage advances and signs of senescence are evident.

Scavenging capacity of coffee brews against oxygen and nitrogen reactive species and the correlation with bioactive compounds by multivariate analysis

In the present work the scavenging capacity of coffee brews against ROS (ROO, H2O2, HO and HOCl) and RNS (NO and ONOO−) was evaluated and correlated with their bioactive compounds by multivariate analysis. It is the first time that the complete antioxidant capacity profile of coffee brews against different ROS and RNS is evaluated and that the capacity of coffee brews to scavenge NO is reported. The coffee brews were able to scavenge all the reactive species tested and possibly NO2 and CO3−. The capacity of the coffee brews to scavenge ROO (2523 to 3673μmol TE/g), HO (IC50=2.24 to 4.38μg/mL), NO (IC50=3.07 to 5.67μg/mL) and ONOO− (IC50=1.29 to 2.88μg/mL) was positively correlated to the contents of chlorogenic acids, chlorogenic acid lactones and p-coumaric acid, while the scavenging capacity against H2O2 (IC50=336 to 531μg/mL) was positively correlated to the content of browned compounds, mainly melanoidins. The coffee brews showed to be potent HOCl scavengers (IC50=5.12 to 11.20μg/mL), which was correlated to the contents of caffeic acid, 5-hydroxymethylfurfural and browned compounds. These results reinforce the hypothesis that the scavenging capacity against ROS/RNS is one of the mechanisms that can explain the association between the consumption of coffee brews and the decreased risk of chronic-degenerative diseases.

Screening of Natural Antioxidants from Selected Medicinal Plants

Medicinal plants contain high levels of natural antioxidants and exhibited strong antioxidant activity. In order to find new sources of natural antioxidants, a screening of natural antioxidants from some Tunisian medicinal plants commonly associated with treatment of some diseases were conducted. The total phenolic compounds, flavonoids, anthocyanins, and hydrolysables tannins were measured, and the antioxidant capacities were evaluated using DPPH and Trolox equivalent antioxidant capacity assays. Results prove that there are important quantities of these compounds in Tunisian medicinal plants. A positive linear correlation between Trolox equivalent antioxidant capacity and the phenolic compound contents suggested that these compounds were a major contributor of antioxidant activity of these plants. The results from this study will help us understand the antioxidant capacity profiles of these medicinal plants, and also investigate new sources of natural antioxidants.

Computational Models for the Determination of Antioxidant Capacity and Phenolics in Dietary Supplements Using Real-Time Proton Transfer Kinetics Data

Hydrogen atom transfer (HAT) underlies free-radical chain-breaking by phenolic compounds. Using linear free energy relationship (LFER) analysis, proton transfer kinetics was hypothesized as a surrogate rate process for HAT. Phenol red is a probe that is easily oxidized to highly absorbing specie by hydroxyl ion. Absorbance decay of oxidized phenol red was induced by incremental proton transfer from a model phenolic (resorcinol). Global best-fit kinetics profile of resorcinol approximates a mono-exponential decay model (R2 = 0.991) as a limiting law. Proton transfer rate constant (Kptt) versus concentration reveal the utility of the slope (?aoc) of the linear plot (r2= 0.990) as a sensitive predictor of phenolic antioxidant capacity. Superior antioxidant capacity profile of a polyphenol-rich dietary supplement: Garcinia kola seed extract, optimally obeyed a mixed linear/mono-exponential decay equation. Model robustness and selectivity for phenolics was achieved by specifying mathematical constraints as acceptance criteria. The method is more biologically relevant for chain-breaking antioxidants than free-radical-based assays because it captures antioxidant structure-function relationships. Further validation studies, using structurally diverse polyphenols, are warranted to ascertain general utility of the kinetic assay for achieving quality by design (QbD) in phenolic dietary supplement products.