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Journal ArticleDOI

Use of a Free Radical Method to Evaluate Antioxidant Activity

01 Jan 1995-Lwt - Food Science and Technology (Academic Press)-Vol. 28, Iss: 1, pp 25-30

AbstractThe 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.

Topics: DPPH (64%), Ascorbic acid (58%), Vanillic acid (55%), Gentisic acid (55%), Gallic acid (55%)

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Citations
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Journal ArticleDOI
TL;DR: Methods available for the measurement of antioxidant capacity are reviewed, presenting the general chemistry underlying the assays, the types of molecules detected, and the most important advantages and shortcomings of each method.
Abstract: Methods available for the measurement of antioxidant capacity are reviewed, presenting the general chemistry underlying the assays, the types of molecules detected, and the most important advantages and shortcomings of each method. This overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. From evaluation of data presented at the First International Congress on Antioxidant Methods in 2004 and in the literature, as well as consideration of potential end uses of antioxidants, it is proposed that procedures and applications for three assays be considered for standardization: the oxygen radical absorbance capacity (ORAC) assay, the Folin-Ciocalteu method, and possibly the Trolox equivalent antioxidant capacity (TEAC) assay. ORAC represent a hydrogen atom transfer (HAT) reaction mechanism, which is most relevant to human biology. The Folin-Ciocalteu method is an electron transfer (ET) based assay and gives reducing capacity, which has normally been expressed as phenolic contents. The TEAC assay represents a second ET-based method. Other assays may need to be considered in the future as more is learned about some of the other radical sources and their importance to human biology.

4,122 citations


Journal ArticleDOI
TL;DR: An overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, is offered, as well as a brief description of the chemistry ofpolyphenols and their occurrence in plant foods.
Abstract: Polyphenols constitute one of the most numerous and ubiquitous groups of plant metabolites and are an integral part of both human and animal diets. Ranging from simple phenolic molecules to highly polymerized compounds with molecular weights of greater than 30,000 Da, the occurrence of this complex group of substances in plant foods is extremely variable. Polyphenols traditionally have been considered antinutrients by animal nutritionists, because of the adverse effect of tannins, one type of polyphenol, on protein digestibility. However, recent interest in food phenolics has increased greatly, owing to their antioxidant capacity (free radical scavenging and metal chelating activities) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Much of the literature refers to a single group of plant phenolics, the flavonoids. This review offers an overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, as well as a brief description of the chemistry of polyphenols and their occurrence in plant foods.

3,570 citations


Journal ArticleDOI
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.
Abstract: Cancer prevention and treatment using traditional Chinese medicines have attracted increasing interest. This study characterizes antioxidant activity and phenolic compounds of traditional Chinese medicinal plants associated with anticancer, comprising 112 species from 50 plant families. The improved ABTS(*+) method was used to systematically assess the total antioxidant capacity (Trolox equivalent antioxidant capacity, TEAC) of the medicinal extracts. The TEAC values and total phenolic content for methanolic extracts of herbs ranged from 46.7 to 17,323 micromol Trolox equivalent/100 g dry weight (DW), and from 0.22 to 50.3 g of gallic acid equivalent/100 g DW, respectively. A positive, significant linear relationship between antioxidant activity and total phenolic content (all R(2) values>/=0.95) showed that phenolic compounds were the dominant antioxidant components in the tested medicinal herbs. Major types of phenolic compounds from most of the tested herbs were preliminarily identified and analyzed, and mainly included phenolic acids, flavonoids, tannins, coumarins, lignans, quinones, stilbenes, and curcuminoids. These medicinal herbs exhibited far stronger antioxidant activity and contained significantly higher levels of phenolics than common vegetables and fruits. Traditional Chinese medicinal plants associated with anticancer might be potential sources of potent natural antioxidants and beneficial chemopreventive agents.

2,348 citations


Cites methods from "Use of a Free Radical Method to Eva..."

  • ...method and Brand-Williams et al. (1995) established the DPPH ....

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  • ...+ method and Brand-Williams et al. (1995) established the DPPH . method....

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Journal ArticleDOI
Abstract: Guava fruit extracts were analyzed for antioxidant activity measured in methanol extract (AOAM), antioxidant activity measured in dichloromethane extract (AOAD), ascorbic acid, total phenolics, and total carotenoids contents. The ABTS, DPPH, and FRAP assays were used for determining both AOAM and AOAD, whereas the ORAC was used for determining only AOAM. Averaged AOAM [mM Trolox equivalent (TE)/g fresh mass (FM)] were 31.1, 25.2, 26.1, and 21.3 as determined by the ABTS, DPPH, FRAP, and ORAC assays, respectively. Averaged AOAD (mM TE/g FM) were 0.44, 0.27, and 0.16 as determined by the ABTS, DPPH, and FRAP assays, respectively. AOAM determined by all assays were well correlated with ascorbic acid (0.61prp0.92) and total phenolics (0.81prp0.97) and also among themselves (0.68prp0.97) but had negative correlation with total carotenoids (� 0.67prp� 0.81).

2,264 citations


Cites background or methods from "Use of a Free Radical Method to Eva..."

  • ... Brand-Williams et al. (1995) with some modifications....

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  • ...(Leong and Shui, 2002; Miller and Rice-Evans, 1997), 2,2diphenyl-1-picrylhydrazyl (DPPH) ( Brand-Williams et al., 1995; Gil et al., 2002), ferric reducing antioxidant power (FRAP) (Benzie and Strain, 1999; Guo et al., 2003; Jimenez-Escrig et al., 2001), and the oxygen radical absorption capacity (ORAC) (Cao et al., 1993; Ou et al., 2001; Prior et al., 2003)....

    [...]

  • ...…of Food Composition and Analysis 19 (2006) 669–675670 (Leong and Shui, 2002; Miller and Rice-Evans, 1997), 2,2- diphenyl-1-picrylhydrazyl (DPPH) (Brand-Williams et al., 1995; Gil et al., 2002), ferric reducing antioxidant power (FRAP) (Benzie and Strain, 1999; Guo et al., 2003; Jimenez-Escrig…...

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  • ...The DPPH assay was done according to the method of Brand-Williams et al. (1995) with some modifications....

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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

2,225 citations


Cites background or methods from "Use of a Free Radical Method to Eva..."

  • ...However, in view of the fact that the rate of reaction varies widely among substrates (Brand-Williams et al., 1995; Bondet et al., 1997), the best practice seems to be to follow the reaction until it has gone to completion (“plateau”) (Lu et al., 2000; Sa′ nchez-Moreno et al., 1999; Yepez et al.,…...

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  • ...The working wavelength of maximum absorbance, λ max , to be used for the absorbance mea- surements is given variously as 515 nm (Bondet et al., 1997; Brand-Williams et al., 1995; GomezAlonso et al., 2003; Lebeau et al., 2000; Sa′ nchezMoreno et al., 1999), 516 nm (Schwarz et al., 2001), 517 nm…...

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  • ...The more recently introduced method of Brand-Williams and colleagues (Brand-Williams et al., 1995) has been used as a reference point by several groups of workers (G O ′ mez-Alonso et al.,...

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  • ...Finally, the originating paper (Blois, 1958) should be consulted by all who use the method, but read in conjunction with the more recent work of Brand-Williams and colleagues (Bondet et al., 1997; Brand-Williams et al., 1995) which indicates that the situation may not always be as simple as that originally presented....

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  • ...Absorbance measurements - wavelength and instrument used The working wavelength of maximum absorbance, λ max , to be used for the absorbance measurements is given variously as 515 nm (Bondet et al., 1997; Brand-Williams et al., 1995; GomezAlonso et al., 2003; Lebeau et al., 2000; Sa nchezMoreno et al., 1999), 516 nm (Schwarz et al....

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