scholarly journals Enrichment and Assessment of the Contributions of the Major Polyphenols to the Total Antioxidant Activity of Onion Extracts: A Fractionation by Flash Chromatography Approach

Antioxidants ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 175 ◽  
Author(s):  
Mohammad Hossain ◽  
Justine Lebelle ◽  
Rares Birsan ◽  
Dilip Rai
Keyword(s):  
Antioxidant Capacity ◽  
Flash Chromatography ◽  
Total Phenol Content ◽  
Antioxidant Power ◽  
Onion Extract ◽  
Antioxidant Capacities ◽  
Total Antioxidant ◽  
Ferric Reducing Antioxidant Power ◽  
Quercetin Glycoside ◽  
Quercetin Aglycone

The present study extensively fractionated crude red onion extract in order to identify the polyphenols which contributed most in the total antioxidant capacity of the onion extract using a flash chromatography system. The flash separations produced 70 fractions which were tested for their total phenol content, total flavonoid content, and antioxidant capacities as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Out of these 70 fractions, four fractions which were representatives of the four major peaks of the flash chromatograms, were further analysed for their constituent polyphenols using liquid chromatography tandem mass spectrometry (LC-MS/MS). The main contributor of onion antioxidant capacity is quercetin glycoside followed by quercetin aglycone although quercetin aglycone had higher antioxidant capacity than its glycosidic counterparts. High abundance of quercetin glycosides such as quercetin-3,4′-diglucoside and quercetin-4′-glucoside had compensated for their relatively low antioxidant capacities. A Higher degree of glycosylation resulted in lower antioxidant capacity. The fractionation approach also contributed in enrichment of the onion antioxidant polyphenols. A >9 folds enrichment was possible by discarding the early fractions (fractions 1–15) which contained the main bulk of the extracts, predominantly sugars.

Determination of total antioxidant capacity of milk by CUPRAC and ABTS methods with separate characterisation of milk protein fractions

2015 ◽  
Vol 82 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Sema Demirci Çekiç ◽  
Aslı Demir ◽  
Kevser Sözgen Başkan ◽  
Esma Tütem ◽  
Reşat Apak
Keyword(s):  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Milk Protein ◽  
Skim Milk ◽  
Protein Fractions ◽  
Relative Standard Error ◽  
Antioxidant Power ◽  
Antioxidant Capacities ◽  
Relative Standard ◽  
Total Antioxidant

Most milk-applied antioxidant assays in literature are based on the isolation and quantification of individual antioxidative compounds, whereas total antioxidant capacity (TAC) gives a more holistic picture due to cooperative action of antioxidants. Recently, the cupric reducing antioxidant capacity (CUPRAC) method has been modified to measure the antioxidant capacities of thiol-containing proteins, where the classical ammonium acetate buffer – that may otherwise precipitate proteins– was replaced with concentrated urea buffer (able to expose embedded thiol groups of proteins to oxidative attack) adjusted to pH 7.0. Thus, antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid))/persulphate, because only these assays were capable of evaluating protein contribution to the observed TAC value. As milk fat caused turbidity, experiments were carried out with skim milk or defatted milk samples. To determine TAC, modified CUPRAC method was applied to whole milk, separated and redissolved protein fractions, and the remaining liquid phase after necessary operations. Both TAC methods were investigated for their dilution sensitivity and antioxidant power assessment of separate milk fractions such as casein and whey. Proteins like β-lactoglobulin and casein (but not simple thiols) exhibited enhanced CUPRAC reactivity with surfactant (SDS) addition. Addition of milk protein fractions to whole skim milk produced significant ‘negative-biased’ deviations (up to −26% relative standard error) from TAC absorbance additivity in the application of the ABTS method, as opposed to that of the CUPRAC method less affected by chemical deviations from Beer's law thereby producing much smaller deviations from additivity (i.e. the property of additivity is valid when the measured TAC of a mixture is equal to the sum of individual antioxidant capacities of its constituents).

Total Antioxidant Capacity with Peak Specificity via Reaction Flow Chromatography and the Ferric Reducing Antioxidant Power Assay

2019 ◽  
Vol 13 (3) ◽  
pp. 608-616 ◽  
Author(s):  
Andrew Jones ◽  
Agustín Acquaviva ◽  
Thirada Suktham ◽  
Gary R. Dennis ◽  
R. Andrew Shalliker ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Antioxidant Power ◽  
Total Antioxidant ◽  
Ferric Reducing Antioxidant Power

scholarly journals Chemical Characterization and Antioxidant Activity of Cedrus atlantica Manetti Tar (Atlas Cedar Tar)

2020 ◽  
Vol 8 (2) ◽  
pp. 244-255
Author(s):  
Inssaf Skanderi ◽  
Ourida Chouitah
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Condensed Tannins ◽  
Chemical Characterization ◽  
Antioxidant Power ◽  
Cedrus Atlantica ◽  
Total Antioxidant ◽  
Ferric Reducing Antioxidant Power ◽  
Total Polyphenolic Content

Cedrus atlantica Manetti Tar was analyzed by gas chromatography coupled to mass spectrometry, it was subjected to analyzes to know their total polyphenolic and condensed tannins contents, also their Ferric-reducing antioxidant power and Total antioxidant capacity. Chemical characterization identified 88 constituents where Himachalene and α-atlantone isomers (14.51 % - 4.07 %), Calacorene (3.52 %) and ar-Turmerone 3.35 %, were the major components, the total polyphenolic content and condensed tannins contents were 57.15 ± 0.15 milligrams equivalent of gallic acid /g tar and 4.41 ± 0.05 milligrams equivalent of catechin /g tar respectively .This extract showed remarkable Ferric-reducing antioxidant power with effective concentration equal to 50 ± 0.075 mg /mL ± 0,00028 and total antioxidant capacity equal to 262.75 mg equivalents of ascorbic acid /g tar ± 14,43. The experimental results indicated that our tar has promotive antioxidant activity.

Total Antioxidant Capacity of Thai Herbal Teas by the Ferric Reducing Antioxidant Power

2019 ◽  
Vol 886 ◽  
pp. 46-51
Author(s):  
Techaoei Surachai ◽  
Jarmkom Khemjira ◽  
Khobjai Warachate
Keyword(s):  
Vitamin C ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Herbal Tea ◽  
Frap Assay ◽  
Antioxidant Power ◽  
Intermediate Activity ◽  
Total Antioxidant ◽  
Ferric Reducing Antioxidant Power

The main objective aimed to compare in vitro antioxidant power of different recipes of Thai herbal teas including of Tatirot, Krajeab, Kamfoi, and Kesorn Bua. The ferric reducing/antioxidant power (FRAP) assay was used to measure the total antioxidant power of freshly brewed tea. Results showed that different Thai tea recipes had slightly different in vitro antioxidant power. The herbal teas recipe was expressed as µM of antioxidant power/g of dried Thai tea recipes. Values ranges as 555.62±0.77-908.43±0.69 µM/1g of Thai herbal tea, especially Krajeab tea showed strongly antioxidant of 908.43±0.69 µM/1g of tea when compared with other samples. Therefore, it has confirmed that the antioxidant power of Thai herbal tea recipes is considerably intermediate activity than vitamin C

scholarly journals Enzyme Inhibitory Properties, Antioxidant Activities, and Phytochemical Profile of Three Medicinal Plants from Turkey

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Gokhan Zengin ◽  
Gokalp Ozmen Guler ◽  
Abdurrahman Aktumsek ◽  
Ramazan Ceylan ◽  
Carene Marie Nancy Picot ◽  
...  
Keyword(s):  
Medicinal Plants ◽  
Antioxidant Capacity ◽  
Antioxidant Activities ◽  
Ferrous Ions ◽  
Antioxidant Power ◽  
Key Enzymes ◽  
Total Antioxidant ◽  
Ferric Reducing Antioxidant Power ◽  
Inhibitory Potential

We aimed to investigate the inhibitory potential of three medicinal plants (Hedysarum varium,Onobrychis hypargyrea, andVicia truncatula) from Turkey against key enzymes involved in human pathologies, namely, diabetes (α-amylase andα-glucosidase), neurodegenerative disorders (tyrosinase, acetylcholinesterase, and butyrylcholinesterase), and hyperpigmentation (tyrosinase). The antioxidant potential, phenolic and flavonoid content of ethyl acetate, and methanolic and aqueous extracts were investigated usingin vitroassays. The total antioxidant capacity (TAC),β-carotene/linoleic acid bleaching activity, 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH•), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), cupric ion reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), and metal chelating activity on ferrous ions were used to evaluate the antioxidant capabilities of the extracts. The half-maximal inhibitory concentrations (IC50) of the extracts on cholinesterase, tyrosinase, andα-amylase were significantly higher than the references, galantamine, kojic acid, and acarbose, respectively. The half-maximal effective concentrations (EC50) of the extracts on TAC, CUPRAC, and FRAP were significantly higher than trolox. The phenol and flavonoid contents of the plant extracts were in the range20.90±0.190–83.25±0.914 mg gallic acid equivalent/g extract and1.45±0.200–39.71±0.092 mg rutin equivalent/g extract, respectively. The plants were found to possess moderate antioxidant capacities and interesting inhibitory action against key enzymes.

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

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
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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