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

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.

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

Antioxidants ◽

10.3390/antiox8070215 ◽

2019 ◽

Vol 8 (7) ◽

pp. 215 ◽

Cited By ~ 18

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.

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Antioxidants from Tropical Herbs

Natural Product Communications ◽

10.1177/1934578x1000500321 ◽

2010 ◽

Vol 5 (3) ◽

pp. 1934578X1000500 ◽

Cited By ~ 5

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.

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Exploring the Antioxidant Features of Polyphenols by Spectroscopic and Electrochemical Methods

Antioxidants ◽

10.3390/antiox8110523 ◽

2019 ◽

Vol 8 (11) ◽

pp. 523 ◽

Cited By ~ 6

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.

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

Antioxidants ◽

10.3390/antiox11010155 ◽

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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Antioxidant Potential of Grass Pea Seeds from European Countries

Foods ◽

10.3390/foods7090142 ◽

2018 ◽

Vol 7 (9) ◽

pp. 142 ◽

Cited By ~ 7

Author(s):

Wojciech Rybiński ◽

Magdalena Karamać ◽

Katarzyna Sulewska ◽

Andreas Börner ◽

Ryszard Amarowicz

Keyword(s):

Phenolic Compounds ◽

Total Phenolics ◽

Trolox Equivalent Antioxidant Capacity ◽

Total Phenolic ◽

Grass Pea ◽

Antioxidant Power ◽

Phenolic Contents ◽

Trolox Equivalent ◽

Ferric Reducing Antioxidant Power ◽

Derivatives Of

Phenolic compounds were extracted from seeds of 30 varieties of grass pea (Lathyrus sativus) into 80% (v/v) methanol. The total phenolics compounds content of the extracts and their antioxidant activity were determined using Folin-Ciocalteu’s phenol reagent and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric-reducing antioxidant power (FRAP) methods, respectively. Total phenolic contents ranged from 1.88 to 7.12 mg/g extract and 20.3 to 70.3 mg/100 g seeds. The extracts and seeds were characterized using Trolox equivalent antioxidant capacity values of 0.015–0.037 mmol Trolox/g extract and 0.158–0.372 mmol Trolox/100 g seeds, and FRAP values of 0.045–0.120 mmol Fe2+/g extract and 0.487–1.189 Fe2+/100 g seeds. The total phenolics content of grass pea extract was correlated with the results of the ABTS (r = 0.881) and FRAP (r = 0.781) assays. The same correlation was observed between the results of both assays (r = 0.842). Two derivatives of p-coumaric acid were the dominant phenolic compounds of the Derek cultivar of grass pea.

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Biochemical content, minerals, and antioxidant activity of fruit jiaosu obtained by natural fermentation

Food Research ◽

10.26656/fr.2017.5(3).714 ◽

2021 ◽

Vol 5 (3) ◽

pp. 423-430

Author(s):

P.A. Hnin ◽

Y.C. Kam ◽

N.W. Sit

Keyword(s):

Antioxidant Activity ◽

Organic Acid ◽

Protein Concentration ◽

Antioxidant Activities ◽

Total Phenolic ◽

Antioxidant Power ◽

Natural Fermentation ◽

Trolox Equivalent ◽

Ferric Reducing Antioxidant Power ◽

Raw Honey

This study was conducted to determine the pH, protein concentration, mineral, phenolic, flavonoid, and organic acid contents, as well as the antioxidant activity of three batches of fruit jiaosu (F1B3, F1B4, and F1B5). The jiaosu was prepared by mixing ten types of fresh fruits, raw honey, and water (3:1:10, w/w/w), and fermented at room temperature for six months. All fruit jiaosu had low pH (2.96–3.69), and the protein concentration was ranged from 8.45 to 16.2 µg/mL. Potassium (605.0–657.2 mg/L) was found to be the most abundant mineral in all the samples, followed by magnesium, calcium, and sodium. The total phenolic and flavonoid contents were 183.1–210.5 µg gallic acid equivalent/mL and 45.2–53.8 µg quercetin equivalent/mL, respectively. Acetic acid was the major organic acid in the F1B4 and F1B5 samples (6.58 g/L and 20.7 g/L, respectively) while the F1B3 sample contained the highest amount of lactic acid (12.1 g/L). Ascorbic and citric acids were present in small amounts in all samples. All the samples showed stronger scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radicals (half-maximum inhibitory concentration, IC50: 13.6–16.8% v/v) than against hydrogen peroxide (IC50: 47.2–50.6% v/ v). The ferric reducing antioxidant power and oxygen radical absorbance capacity values for the samples were 14.9–20.9 µg ascorbic acid equivalent/mL and 23.9–25.4 mg Trolox equivalent/mL, respectively. The results indicated that the fruit jiaosu is a complex acidic solution containing proteins, minerals, phenolic compounds, and organic acids with antioxidant activities. Natural fermentation may cause variations in the organic acid content of the fruit jiaosu.

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

Journal of the Serbian Chemical Society ◽

10.2298/jsc190404139g ◽

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.

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Effect of fertilization and harvesting time on antioxidant activity of three leafy vegetables commonly used in Benin

African Journal of Food, Agriculture, Nutrition and Development ◽

10.18697/ajfand.60.12970 ◽

2013 ◽

Vol 13 (60) ◽

pp. 8293-8312

Author(s):

CNA Sossa-Vihotogbé ◽

◽

NH Akissoe ◽

VB Anihouvi ◽

BC Ahohuendo ◽

...

Keyword(s):

Antioxidant Activity ◽

Antioxidant Activities ◽

Leafy Vegetables ◽

Organic Fertilizers ◽

Total Phenolic ◽

Antioxidant Power ◽

Harvesting Time ◽

Total Antioxidant ◽

Ferric Reducing Antioxidant Power

Leafy vegetables are an excellent source of bioactive factors, traditionally used as important medical ingredients. Recently, some leafy vegetables are domesticated without the use of fertilizer, as well as the assessment of the effect of fertilizer on their nutritional value. This study aims at testing the effect of three mineral and organic fertilizers (Cowpat, NPK and NPK + cowpat) on three traditional leafy vegetables: Ceratotheca sesamoïdes, Sesamum radiatum and Justicia tenella. Their antioxidant activities were assessed at different harvesting times varying from six (6) to fourteen (14) Weeks After Transplantation (WAT) using three in vitro methods: Ferric reducing antioxidant power (FRAP), 2,2’-Azinobis3-ethylbenzothiazoline-6- sulfonic acid (ABTS) and 2,2-diphenyl-1-picryl hydrazil (DPPH). The FRAP, DPPH, ABTS assays were consistent and positively correlated (p < 0.001). Total antioxidant activities of leafy vegetables depended on species, harvesting time and methods. They ranged from 32.0 to 45.7 µmol Fe/g DW (for FRAP), with non fertilized J. tenella cut at 12 WAT giving the highest antioxidant activity. Percentage of inhibition using DPPH assay ranged from 11.4 to 87.2 % and showed that J. tenella fertilized with NPK and cowpat, and harvested at 9 WAT had the highest antioxidant activity. Regarding ABTS, the range of 17.6 to 28.9 µmol TE/g DW was recorded, and the leaves of C. sesamoïdes harvested at 10 WAT and fertilized with cowpat showed the highest level. Compared to other species, those studied here may best contribute to improve human health related to degenerative diseases. Moreover, significant and positive correlations were observed between the total phenolic compounds content and antioxidant activities of leaves regardless the methods used. The positive and significant correlations between the three assays (FRAP, DPPH, ABTS) allow to suggest the use of only anyone of them to check factors in the study. This paper highlights the potential of antioxidant capability of the leafy vegetables even fertilized.

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Antioxidant Capacities of Peel, Pulp, and Seed Fractions ofCanarium odontophyllumMiq. Fruit

Journal of Biomedicine and Biotechnology ◽

10.1155/2010/871379 ◽

2010 ◽

Vol 2010 ◽

pp. 1-8 ◽

Cited By ~ 22

Author(s):

K. Nagendra Prasad ◽

Lye Yee Chew ◽

Hock Eng Khoo ◽

Kin Weng Kong ◽

Azrina Azlan ◽

...

Keyword(s):

Antioxidant Activities ◽

Natural Antioxidants ◽

Total Phenolic ◽

Antioxidant Power ◽

Hemoglobin Oxidation ◽

Antioxidant Capacities ◽

Total Antioxidant ◽

Ferric Reducing Antioxidant Power ◽

Canarium Odontophyllum

Antioxidant capacities of ethylacetate, butanol, and water fractions of peel, pulp, and seeds ofCanarium odontophyllumMiq. (CO) were determined using variousin vitroantioxidant models. Ethylacetate fraction of peel (EAFPE) exhibited the highest total phenolic (TPC), total flavonoid content (TFC), and antioxidant activities compared to pulp, seeds, and other solvent fractions. Antioxidant capacities were assayed by total antioxidant capability, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical activity, ferric reducing antioxidant power (FRAP), and hemoglobin oxidation assay. Total phenolic content of ethylacetate fractions was positively correlated with the antioxidant activity. This is the first report on the antioxidant activities from CO fruit fractions. Thus, EAFPE can be used potentially as a readily accessible source of natural antioxidants and as a possible pharmaceutical supplement.

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Changes in the Total Polyphenolic Content and Antioxidant Capacities of Perilla (Perilla frutescensL.) Plant Extracts during the Growth Cycle

Journal of Food Quality ◽

10.1155/2017/7214747 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

Francesco Gai ◽

Pier Giorgio Peiretti ◽

Magdalena Karamać ◽

Ryszard Amarowicz

Keyword(s):

Phenolic Compound ◽

Growth Cycle ◽

Vegetative Stage ◽

Trolox Equivalent Antioxidant Capacity ◽

Total Phenolic ◽

Growth Stages ◽

Antioxidant Power ◽

Full Flowering ◽

Trolox Equivalent ◽

Ferric Reducing Antioxidant Power

Changes in the total polyphenolics and antioxidative capacity of the perilla (Perilla frutescensL.) plant, during the growth cycle, have been analyzed in this study. These parameters were evaluated at five morphological stages. The extracts characterized by the highest total phenolic compound content were obtained at the full flowering stage. The phenolic compound profile was characterized by the presence of three major compounds, with rosmarinic acid being the most abundant. Moreover, their contents were significantly different according to the growth stage. High Trolox equivalent antioxidant capacity values were found for the last two growth stages. The lowest ferric-reducing antioxidant power value was observed for the medium vegetative stage. The highest antiradical activity against DPPH•was observed for extracts obtained from the early vegetative stage. The antioxidant activity changes during the growth cycle, and this change may be useful to determine the optimal harvest time.

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