scholarly journals Exploring the Antioxidant Features of Polyphenols by Spectroscopic and Electrochemical Methods

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 523 ◽  
Author(s):  
Berta Alcalde ◽  
Mercè Granados ◽  
Javier Saurina
Keyword(s):  
Antioxidant Activities ◽  
Reference Electrode ◽  
Principal Component ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Hydroxyl Groups ◽  
Antioxidant Power ◽  
Chemical Structures ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power ◽  
Comprehensive Study

This paper evaluates the antioxidant ability of polyphenols as a function of their chemical structures. Several common food indexes including Folin-Ciocalteau (FC), ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays were applied to selected polyphenols that differ in the number and position of hydroxyl groups. Voltammetric assays with screen-printed carbon electrodes were also recorded in the range of −0.2 to 0.9 V (vs. Ag/AgCl reference electrode) to investigate the oxidation behavior of these substances. Poor correlations among assays were obtained, meaning that the behavior of each compound varies in response to the different methods. However, we undertook a comprehensive study based on principal component analysis that evidenced clear patterns relating the structures of several compounds and their antioxidant activities.

scholarly journals Phenolic Profiles and Antioxidant Activities of 30 Tea Infusions from Green, Black, Oolong, White, Yellow and Dark Teas

Antioxidants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 215 ◽  
Author(s):  
Cai-Ning Zhao ◽  
Guo-Yi Tang ◽  
Shi-Yu Cao ◽  
Xiao-Yu Xu ◽  
Ren-You Gan ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Dry Weight ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Total Phenolic ◽  
Antioxidant Power ◽  
Phenolic Contents ◽  
Tea Infusions ◽  
Phenolic Profiles ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power

Tea is among the most consumed drink worldwide, and its strong antioxidant activity is considered as the main contributor to several health benefits, such as cardiovascular protection and anticancer effect. In this study, the antioxidant activities of 30 tea infusions, which were obtained by the mimic of drinking tea of the public, from green, black, oolong, white, yellow and dark teas, were evaluated using ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, ranging from 504.80 ± 17.44 to 4647.47 ± 57.87 µmol Fe2+/g dry weight (DW) and 166.29 ± 24.48 to 2532.41 ± 50.18 µmol Trolox/g DW, respectively. Moreover, their total phenolic contents (TPC) were detected by Folin-Ciocalteu assay and were in the range of 24.77 ± 2.02 to 252.65 ± 4.74 mg gallic acid equivalent (GAE)/g DW. Generally, Dianqing Tea, Lushan Yunwu Tea, and Xihu Longjing Tea showed the strongest antioxidant activities among 30 teas. Furthermore, the phenolic compounds in tea infusions were identified and quantified, with catechins most commonly detected, especially in green tea infusions, which were main contributors to their antioxidant activities. Besides tea polyphenols, considerable content of caffeine also presented in 30 tea infusions.

scholarly journals Antioxidants from Tropical Herbs

2010 ◽  
Vol 5 (3) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Rasyidah Razab ◽  
Azlina Abdul Aziz
Keyword(s):  
Free Radicals ◽  
Antioxidant Capacity ◽  
Strong Correlation ◽  
Antioxidant Activities ◽  
Polyphenolic Compounds ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Antioxidant Power ◽  
Polyphenolic Content ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power

Plants that contain high amounts of polyphenolic compounds are potential candidates for natural antioxidant sources. Studies are on going in the search for new sources of antioxidants. Not much data are available on the antioxidant capacity of tropical herbs. With this in mind, 19 commonly consumed Malaysian herbs were analyzed for their polyphenolic content and antioxidant activities. A majority of these plants have never been studied before with regards to their polyphenolic content and antioxidant activities. The shoots of Anacardium occidentale, the shoots and fruits of Barringtonia racemosa, Pithecellobium jiringa and Parkia speciosa had high polyphenolic contents (> 150 μg gallic acid equivalents/mg dried plant) and antioxidant activities when measured using the ferric reducing antioxidant power (FRAP) (>1.2 mM) and Trolox equivalent antioxidant capacity (TEAC) assays (>2.4 mM). A strong correlation was observed between the two antioxidant assays (FRAP vs TEAC) implying that the plants could both scavenge free radicals and reduce oxidants. There was also a strong correlation between the antioxidant activities and polyphenolic content suggesting the observed antioxidant activities were contributed mainly by the polyphenolics in the plants.

scholarly journals Antioxidant activities and inhibitory effects of free and bound polyphenols from date (Phoenix dactylifera L.) seeds on starch digestive enzymes

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Sameera Sirisena ◽  
Ken Ng ◽  
Said Ajlouni
Keyword(s):  
Antioxidant Activities ◽  
Phoenix Dactylifera ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Total Phenolic ◽  
Antioxidant Power ◽  
Food Ingredients ◽  
Phoenix Dactylifera L ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power

Date (Phoenix dactylifera L.) seeds have gained interest as a valuable by-product of  the date fruit industry and have been identified as a rich source of functional and bioactive ingredients. In this study, date seeds from five varieties (Medjool, Deglet Nour, Barhee, Bou Sthammi and Dayrie) cultivated in Australia were analysed for their total phenolic and flavonoid contents, ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), and in-vitro inhibition against α-amylase and α-glucosidase. The date seed powders (DSP) were extracted with acetone-methanol-water (2:2:1, v:v:v) to obtain free polyphenols.  The bound polyphenols were extracted from the residual solids with butanol-HCl (97.5:2.5; v/v) treatment at 100 °C. The greatest quantities of total phenols (4166±227 mg Gallic Acid Equivalents 100g-1 DSP), total flavonoids (52.1±9.6 mg Quercetin Equivalents 100g-1 DSP), FRAP (1589±47 µmol Iron[II] Equivalents g-1 DSP) and TEAC (45.2±1.4 µmol Trolox Equivalents g-1 DSP) were detected in seeds from Deglet Nour variety. Both free and bound polyphenol fractions showed significant (p<0.05) inhibition against rat intestinal α-glucosidase with little or no inhibition against pancreatic α-amylase. Bound polyphenols showed stronger α-glucosidase inhibition compared with free polyphenols.  The IC50 for α-glucosidase were reported as mg GAE mL-1 ranged from 0.39±0.02 (Deglet Nour) to 0.68±0.02 (Medjool) for bound polyphenols, and from 0.907±0.08 (Medjool) to 1.75±0.15 (Barhee-khalal) for free polyphenols. Bound polyphenol fraction, with strong α-glucosidase inhibition and weak α-amylase inhibition, was suggested as a significant source of functional food ingredients with anti-hyperglycaemic properties.

scholarly journals Bioactive Phenolic Metabolites from Adriatic Brown Algae Dictyota dichotoma and Padina pavonica (Dictyotaceae)

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1187
Author(s):  
Ivana Generalić Mekinić ◽  
Vida Šimat ◽  
Viktorija Botić ◽  
Anita Crnjac ◽  
Marina Smoljo ◽  
...  
Keyword(s):  
Total Phenolics ◽  
Antioxidant Activities ◽  
Principal Component ◽  
Ultrasound Assisted Extraction ◽  
Antioxidant Power ◽  
Dictyota Dichotoma ◽  
Assisted Extraction ◽  
Sample Data ◽  
Ferric Reducing Antioxidant Power ◽  
The Individual

In this study, the influences of temperature (20, 40 and 60 °C) and extraction solvents (water, ethanol) on the ultrasound-assisted extraction of phenolics from the Adriatic macroalgae Dictyota dichotoma and Padina pavonica were studied. The extracts were analysed for major phenolic sub-groups (total phenolics, flavonoids and tannins) using spectrometric methods, while the individual phenolics were detected by HPLC. The antioxidant activities were evaluated using three methods: Ferric Reducing/Antioxidant Power (FRAP), scavenging of the stabile 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and Oxygen Radical Antioxidant Capacity (ORAC). The aim of the study was also to find the connection between the chemical composition of the extracts and their biological activity. Therefore, principal component analysis (PCA), which permits simple representation of different sample data and better visualisation of their correlations, was used. Higher extraction yields of the total phenolics, flavonoids and tannins were obtained using an alcoholic solvent, while a general conclusion about the applied temperature was not established. These extracts also showed good antioxidant activity, especially D. dichotoma extracts, with high reducing capacity (690–792 mM TE) and ORAC values (38.7–40.8 mM TE in 400-fold diluted extracts). The PCA pointed out the significant influence of flavonoids and tannins on the investigated properties. The results of this investigation could be interesting for future studies dealing with the application of these two algae in foods, cosmetics and pharmaceuticals.

scholarly journals Chemical and Cellular Antioxidant Activities of In Vitro Digesta of Tilapia Protein and Its Hydrolysates

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 833
Author(s):  
Xiaogang Zhang ◽  
Parinya Noisa ◽  
Jirawat Yongsawatdigul
Keyword(s):  
Structural Modification ◽  
Physiological Condition ◽  
Antioxidant Activities ◽  
Protein Hydrolysate ◽  
Principal Component ◽  
Hydrogen Atom Transfer ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Degree Of Hydrolysis ◽  
Trolox Equivalent

Production of protein hydrolysate as nutraceuticals is typically based on the activity of the hydrolysate, which might not yield the optimal activity under physiological condition due to structural modification of peptides upon gastrointestinal (GI) digestion. This study systematically compared the chemical and cellular antioxidant activities of the in vitro digesta of tilapia protein and its hydrolysates prepared with various degree of hydrolysis (DH) by Alcalase. The enzymes used in the in vitro GI digestion analysis significantly contributed to the peptide content, Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC). Proteins and all hydrolysates were slightly digested by pepsin but hydrolyzed extensively by pancreatin. Both hydrolysate and digesta predominantly scavenged free radicals via hydrogen atom transfer (HAT). The antioxidant activities of the hydrolysates increased with the increasing DH up to 16 h of hydrolysis. However, the digesta of 10-h hydrolysate displayed the highest chemical and HepG2 cellular antioxidant activities, while the protein digesta displayed the lowest. Principal component analysis (PCA) showed that the TEAC of the digesta was positively correlated with the cellular antioxidant activity (CAA). Therefore, the production of protein hydrolysate should be optimized based on the activity of the hydrolysate digesta rather than that of hydrolysates.

scholarly journals Potential of Baccharis alnifolia Meyen & Walpan (Chilka) from northern Chile used as a medicinal infusion

2019 ◽  
Vol 49 (10) ◽  
Author(s):  
Emilio Soto ◽  
Luis Bustos ◽  
Mario Juan Simirgiotis ◽  
Claudio Parra
Keyword(s):  
Antioxidant Capacity ◽  
Ethanolic Extract ◽  
Ethanol Extract ◽  
Dry Weight ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Antioxidant Power ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power ◽  
Chilean Altiplano ◽  
First Time

ABSTRACT: Baccharis alnifolia Meyen & Walp. is a native and medicinal, Chilean Altiplano herb that is used as a poultice and also consumed as an infusion to relieve inflammation. This study evaluated the antioxidant and cytotoxic effect of the ethanolic extract of B. alnifolia and their infusion. It was reported that the ethanol extract contains 4.42 mg GAE/g of dry weight and the infusion contains 35.86 mg GAE/L of total polyphenols. Also, it determined the antioxidant capacity using Ferric reducing antioxidant power (FRAP), Oxygen Radical Absorbance Capacity (ORAC) and Trolox equivalent antioxidant capacity (TEAC) assay. Moreover, seven metabolites including between phenolic acids and flavonoids were identified for the first time in both extracts of the medicinal plant Baccharis alnifolia. The UHPLC-DAD chromatograms revealed the majority presence of ferulic acid and luteolin, both could be responsible for the antioxidant and cytotoxic activity. Furthermore, we realized a preliminary screening of cytotoxicity in different tumor cell lines, finding that these extracts have cytotoxic potential on kidney cells.

scholarly journals Serbian aromatized wine “Bermet”: Electrochemical, chemiluminescent and spectrophotometric determination of antioxidant activity

2020 ◽  
Vol 85 (4) ◽  
pp. 517-529
Author(s):  
Stanislava Gorjanovic ◽  
Ferenc Pastor ◽  
Sofia Loupassaki ◽  
Mile Veljovic ◽  
Predrag Vukosavljevic ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Integrated Approach ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Total Phenolic ◽  
Equal Weight ◽  
Antioxidant Power ◽  
15Th Century ◽  
Traditional Procedure ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power

Serbian aromatized wine ?Bermet? from grapes grown on Fruska Gora Mountain has been in production since the 15th century. Ten commercial Bermets produced according to the traditional procedure by different manufacturers, and six prepared within the scope of this study were assessed for antioxidant (AO) activity using electrochemical, chemiluminescent and spectrophotometric AO assays. Direct current polarographic assay based on the decrease of anodic current of [hydrogen(peroxido)(1-)]hydroxidomercury(II) complex formation in alkaline H2O2 solution at potential of mercury oxidation, chemiluminescent H2O2 scavenging assay, as well as commonly used spectrophotometric assays (2,2?-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) based Trolox equivalent antioxidant capacity (TEAC), 2,2-diphenyl-1- picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP)) were used. Total phenolic content (TPC) was determined by Folin?Ciocalteu assay. The results obtained were correlated using regression analysis, ANOVA and F-test. An integrated approach to AO capacity determination allowed a more comprehensive comparison between samples. The approach is based on the introduction of the relative antioxidant capacity index, calculated by assigning each AO assay equal weight, and by PCA analysis. In addition, the introduction of phenolic antioxidant coefficients, calculated as the ratio between individual AO capacity and TPC, enabled a better understanding of their relation.

scholarly journals Evaluation on Antioxidant Effect of Xanthohumol by Different Antioxidant Capacity Analytical Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xiu-Li Zhang ◽  
Yong-Dong Zhang ◽  
Tao Wang ◽  
Hong-Yun Guo ◽  
Qi-Ming Liu ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Radical Reaction ◽  
Reaction System ◽  
Antioxidant Effect ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Dpph Radical ◽  
Antioxidant Power ◽  
Scavenging Effect ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power

Several assays have been frequently used to estimate antioxidant capacities includingABTS•+, DPPH, and FRAP assays. Xanthohumol (XN), the major prenylated flavonoid contained in beer, witnessed various reports on its antioxidant capacity. We systematically evaluated the antioxidant activity of XN using three systems, 2,2,-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS•+) scavenging assays, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assays, and ferric reducing antioxidant power (FRAP) assays. The results are expressed as Trolox equivalent antioxidant capacity (TEAC). The TEAC of XN was0.32±0.09 μmol·l−1by the ABTS assay and0.27±0.04 μmol·l−1by the FRAP. Meanwhile, the XN did not show obviously scavenging effect on DPPH radical reaction system. These results showed that different methods in the evaluation of compound antioxidant capicity, there may be a different conclusion.

scholarly journals Effect of flavonoids content on antioxidant activity of commercial cosmetic plant extracts

2013 ◽  
Vol 59 (3) ◽  
pp. 63-75 ◽  
Author(s):  
Paulina Malinowska
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Capacity ◽  
Plant Extracts ◽  
Natural Antioxidants ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Antioxidant Power ◽  
Trolox Equivalent ◽  
Ferric Reducing Antioxidant Power ◽  
The Relationship ◽  
Herb Extracts

Abstract The aim of this work was to evaluate the antioxidant capacity and flavonoids content in 10 commercial cosmetic plant extracts used in cosmetics industry. Antioxidant activity of plant extracts were measured using two methods: FRAP (Ferric Reducing Antioxidant Power) and TEAC (Trolox Equivalent Antioxidant Capacity). The relationship between flavonoids content and antioxidant capacity of plant extracts were checked. As a result of this research it was found that FRAP and TEAC values of plant extracts significantly depend on the flavonoids content. The highest antioxidant activity, both in FRAP and TEAC assays, was observed for arnica flowers, hawthorn flowers and lungwort herb extracts. These extracts can be used as source of natural antioxidants for the prolongation of the oxidative stability of cosmetic products. Additionally, they can replace synthetic antioxidants

scholarly journals Fermentation with Tea Residues Enhances Antioxidant Activities and Polyphenol Contents in Kombucha Beverages

Antioxidants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 155
Author(s):  
Dan-Dan Zhou ◽  
Adila Saimaiti ◽  
Min Luo ◽  
Si-Yu Huang ◽  
Ruo-Gu Xiong ◽  
...  
Keyword(s):  
Green Tea ◽  
High Performance ◽  
Antioxidant Activities ◽  
Black Tea ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Total Phenolic ◽  
Array Detector ◽  
Antioxidant Power ◽  
Phenolic Contents ◽  
Trolox Equivalent

Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which can be attributed to its abundant bioactive compounds, especially polyphenols. Kombucha is conventionally prepared by fermentation of a sugared black tea infusion without tea residue. In this study, the effects of black tea residue and green tea residue on kombucha were studied, and its antioxidant activities, total phenolic contents, as well as concentrations of polyphenols at different fermentation stages were evaluated using ferric-reducing antioxidant power, Trolox equivalent antioxidant capacity, Folin-Ciocalteu method and high-performance liquid chromatography with a photodiode array detector. The results showed that fermentation with tea residue could markedly increase antioxidant activities (maximum 3.25 times) as well as polyphenolic concentrations (5.68 times) of kombucha. In addition, green tea residue showed a stronger effect than black tea residue. Overall, it is interesting to find that fermentation with tea residues could be a better strategy to produce polyphenol-rich kombucha beverages.

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