Antioxidant and structure–activity relationships (SARs) of some phenolic and anilines compounds
TL;DR: The scavenging behavior of a series of phenolic and anilines compounds toward H2O2 and DPPH was examined in this paper, where wide differences among compounds in each series and between the two series were observed.
About: This article is published in Annals of Agricultural Sciences.The article was published on 2013-12-01 and is currently open access. It has received 409 citations till now. The article focuses on the topics: DPPH.
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01 Jan 2019
TL;DR: The most common in vitro methods used to evaluate antioxidant activity of phenolic compounds are in-vitro methods which are based on single electron transfer reaction or single hydrogen atom transfer reaction as mentioned in this paper.
Abstract: Phenolic compounds are the most abundant antioxidants in the human diet. They have a considerable structural diversity, characterized by the hydroxyl groups on aromatic rings. According to the number of phenol rings and the structural elements that bind rings to one another, such compounds are grouped and classified as simple phenols, phenolic acids, flavonoids, xanthones, stilbenes, and lignans. Each group has different mechanisms of action correlated to a structural specificity, which confer the antioxidant properties to the compounds. They act mainly in scavenging reactive species of oxygen, nitrogen, and chlorine or can also chelate metal ions, acting in both the initiation stage and in the propagation of the oxidative process. The most common in vitro methods used to evaluate antioxidant activity of phenolic compounds are in vitro methods which are based on single electron transfer reaction or single hydrogen atom transfer reaction.
537 citations
11 Apr 2019
TL;DR: It is demonstrated that these wild edible leafy plants could be a potential source of natural antioxidants and a strong correlation between antioxidant activity with total phenolic and total flavonoid content was found.
Abstract: Eight selected wild vegetables from Nepal (Alternanthera sessilis, Basella alba, Cassia tora, Digera muricata, Ipomoea aquatica, Leucas cephalotes, Portulaca oleracea and Solanum nigrum) were investigated for their antioxidative potential using 2,2-dyphenyl-1-picrylhydrazyl (DPPH) scavenging, hydrogen peroxide (H2O2), ferric reducing antioxidant power (FRAP), and ferric thiocyanate (FTC) methods. Among the selected plant extracts C. tora displayed the highest DPPH radical scavenging activity with an IC50 value 9.898 μg/mL, whereas A. sessilis had the maximum H2O2 scavenging activity with an IC50 value 16.25 μg/mL—very close to that of ascorbic acid (16.26 μg/mL). C. tora showed the highest absorbance in the FRAP assay and the lowest lipid peroxidation in the FTC assay. A methanol extract of A. sessilis resulted in the greatest phenolic content (292.65 ± 0.42 mg gallic acid equivalent (GAE)/g) measured by the Folin–Ciocalteu reagent method, while the smallest content was recorded for B. alba (72.66 ± 0.46 GAE/g). The greatest flavonoid content was observed with extracts of P. oleracea (39.38 ± 0.57 mg quercetin equivalents (QE)/g) as measured by an aluminium chloride colorimetric method, while the least was recorded for I. aquatica (6.61 ± 0.42 QE/g). There was a strong correlation between antioxidant activity with total phenolic (DPPH, R2 = 0.75; H2O2, R2 = 0.71) and total flavonoid content (DPPH, R2 = 0.84; H2O2, R2 = 0.66). This study demonstrates that these wild edible leafy plants could be a potential source of natural antioxidants.
489 citations
Cites background from "Antioxidant and structure–activity ..."
...Phenolic compounds are good electron donors because their hydroxyl groups can directly contribute to antioxidant action [8]....
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TL;DR: The aim of this paper is to present the data about antioxidant activity of polyphenolic compounds with the emphasis on the main factors having influence on their antioxidant activity: chemical structure, ability to form hydrogen bonds, capability of metal ions chelation and reduction, adduct formation and mechanism of antioxidant reaction.
167 citations
Cites background from "Antioxidant and structure–activity ..."
...The presence of di-active groups (-OH) in the compound, –OH with –NH2 and –OH with –OCH3 is responsible for better antioxidant properties of compounds (Bendary et al., 2013; Hoelz et al., 2010)....
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...As mentioned above, the number of hydroxyl groups and other aromatic ring substituents are two main factors associated with the antioxidant activity of phenolic compounds (Bendary et al., 2013)....
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TL;DR: In this paper, the chemical perspective of some methods used to assess the total content of phenolic compounds, flavonoids, anthocyanins, ortho-diphenols, etc.
Abstract: Consumers have sought for functional foods aiming to decrease the risk of various non-communicable diseases, such as diabetes, hypertension, overweight/obesity and principal cardiovascular diseases. Epidemiological and clinical studies are continuously corroborating the fact that individuals with higher intake of (poly)phenolic compounds present lower risk of incidence of non-communicable diseases, especially those related to the cardiovascular system. In this sense, food companies and regulatory health agencies together with academic bodies are investing in analytical methods to screen and typify the phenolic content of food extracts and beverages. In this scenario, this review focuses on the chemical perspective of some methods used to assess the total content of phenolic compounds, flavonoids, anthocyanins, ortho -diphenols, flavonols, and tannins (flavanols), by UV-Vis spectrophotometry, giving emphasis on the structures, reactions, overall positive aspects and limitations of the most used quantitative assays.
114 citations
TL;DR: It was found that the phenolic content significantly increased during germination in all legumes, and germinated peanuts and soybeans obtained maximum phenolics and antioxidant capacity.
Abstract: Bioactive compounds, which are naturally produced in plants, have been concerned with the food and pharmaceutical industries because of the pharmacological effects on humans. In this study, the individual phenolics of six legumes during germination and antioxidant capacity from sprout extracts were determined. It was found that the phenolic content significantly increased during germination in all legumes. Peanuts showed the strongest antioxidant capacity in both the DPPH• (1,1-diphenyl-2-picrylhydrazyl) method and the reducing power assay (32.51% and 84.48%, respectively). A total of 13 phenolic acids were detected and quantified. There were 11 phenolic constituents identified in adzuki beans; 10 in soybeans; 9 in black beans, mung beans, and white cowpeas; and 7 compounds in peanuts. Sinapic acid and cinnamic acid were detected in all six legume sprouts, and their quantities in germinated peanuts were the highest (247.9 µg·g−1 and 62.9 µg·g−1, respectively). The study reveals that, among the investigated legumes, germinated peanuts and soybeans obtained maximum phenolics and antioxidant capacity.
112 citations
Cites background from "Antioxidant and structure–activity ..."
...Principally, the ortho position can create the intramolecular hydrogen bond, so such a position is proposed to be more effective than a para or a meta one [28]....
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References
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TL;DR: The antiradical properties of various antioxidants were determined using the free radical 2,2-Diphenyl-1-picrylhydrazyl (DPPH*) in its radical form as discussed by the authors.
Abstract: The antiradical activities of various antioxidants were determined using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH*). In its radical form. DPPH* has an absorption band at 515 nm which dissappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPH* and shown to follow one of three possible reaction kinetic types. Ascorbic acid, isoascorbic acid and isoeugenol reacted quickly with the DPPH* reaching a steady state immediately. Rosmarinic acid and δ-tocopherol reacted a little slower and reached a steady state within 30 min. The remaining compounds reacted more progressively with the DPPH* reaching a steady state from 1 to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometry of 4 to 6 reduced DPPH* molecules per molecule of antioxidant. Vanillin, phenol, γ-resorcylic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry for the other 13 phenolic compounds varied from one to three reduced DPPH* molecules per molecule of antioxidant. Possible mechanisms are proposed to explain the experimental results.
18,907 citations
"Antioxidant and structure–activity ..." refers background in this paper
...In addition, free radical scavenging is generally the accepted mechanism for antioxidants inhibiting lipid oxidation (Brand-Williams et al., 1995)....
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TL;DR: The factors underlying the influence of the different classes of polyphenols in enhancing their resistance to oxidation are discussed and support the contention that the partition coefficients of the flavonoids as well as their rates of reaction with the relevant radicals define the antioxidant activities in the lipophilic phase.
8,513 citations
"Antioxidant and structure–activity ..." refers background in this paper
...Their antioxidant activity seems to be related to their molecular structure, more precisely to the presence and number of hydroxyl groups, and to double bond conjugation and resonance effects (Rice-Evans et al., 1996)....
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TL;DR: This analysis suggests that the total phenols assay by FCR be used to quantify an antioxidant's reducing capacity and the ORAC assay to quantify peroxyl radical scavenging capacity, to comprehensively study different aspects of antioxidants.
Abstract: This review summarizes the multifaceted aspects of antioxidants and the basic kinetic models of inhibited autoxidation and analyzes the chemical principles of antioxidant capacity assays. Depending upon the reactions involved, these assays can roughly be classified into two types: assays based on hydrogen atom transfer (HAT) reactions and assays based on electron transfer (ET). The majority of HAT-based assays apply a competitive reaction scheme, in which antioxidant and substrate compete for thermally generated peroxyl radicals through the decomposition of azo compounds. These assays include inhibition of induced low-density lipoprotein autoxidation, oxygen radical absorbance capacity (ORAC), total radical trapping antioxidant parameter (TRAP), and crocin bleaching assays. ET-based assays measure the capacity of an antioxidant in the reduction of an oxidant, which changes color when reduced. The degree of color change is correlated with the sample's antioxidant concentrations. ET-based assays include th...
5,354 citations
"Antioxidant and structure–activity ..." refers background in this paper
...The AE value is the result of combination of kinetic and static approaches to characterize the antioxidant efficiency of a molecule (Huang et al., 2005; Roginsky and Lissi, 2005)....
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TL;DR: Traditional Chinese medicinal plants associated with anticancer might be potential sources of potent natural antioxidants and beneficial chemopreventive agents, and contain significantly higher levels of phenolics than common vegetables and fruits.
2,562 citations
Additional excerpts
...7.002 aging itself (Luximon-Ramna et al., 2003; Toyokuni et al., 2003; Caia et al., 2004; Romani et al., 2004)....
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Journal Article•
TL;DR: The use of the stable free radical diphenylpicrylhydrazyl (DPPH) for estimating antioxidant activity and its application in antioxidant research is described.
Abstract: Molyneux, P. The use of the stable free radical diphenylpicrylhydrazyl (DPPH) for estimating antioxidant activity
2,519 citations
"Antioxidant and structure–activity ..." refers background in this paper
...The obtained results were confirmed by the EC50 value ‘‘efficient concentration’’ value (also called the half maximal inhibitory concentration) IC50) value) which is defined as the concentration of substrate that causes 50% loss of the DPPH activity (Molyneux, 2004)....
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