The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Aalt Bast - One of the best experts on this subject based on the ideXlab platform.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
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a new approach to assess the total antioxidant capacity using the teac assay
Food Chemistry, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Sebastiaan J Dallinga, Aalt BastAbstract:Abstract The trolox equivalent antioxidant capacity (TEAC) assay is a popular method for assessing the capacity of a compound to scavenge ABTS radicals (ABTS ). Under the conditions in which the assay is performed, the reaction between most antioxidants and ABTS does not reach completion within the time span applied. This leads to an underestimation of the TEAC of these antioxidants. In the present study, incubations with different concentrations of ABTS and a fixed concentration of antioxidant were performed. The decrease in ABTS concentration in 6 min was plotted against the initial concentration of ABTS and fitted by an exponential function. Extrapolation of the fit to an infinite excess of ABTS gives the maximal concentration of ABTS that can be scavenged by the antioxidant at the concentration employed. This can be used to determine the actual TEAC of antioxidants, i.e. the total antioxidant capacity.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
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a critical appraisal of the use of the antioxidant capacity teac assay in defining optimal antioxidant structures
Food Chemistry, 2003Co-Authors: Mariken J T J Arts, H P Voss, Guido R.m.m. Haenen, Sebastiaan J Dallinga, Aalt BastAbstract:In the Trolox Equivalent Antioxidant Capacity (TEAC) assay, i.e. the capacity of a compound to scavenge the ABTS radical (ABTS•), is assessed. The aim of the present study is to evaluate the applicability of the TEAC assay to predict the antioxidant effectivity of a compound. For this purpose the TEAC assay is compared with other screening assays, such as superoxide scavenging, peroxynitrite scavenging and lipid peroxidation. Of the structurally related compounds, catechol, resorcinol and hydroquinone, resorcinol has the highest TEAC. In contrast, resorcinol appears to have a much lower antioxidant activity than catechol and hydroquinone in other in vitro assays. Similar discrepancies were observed with the flavonoids, chrysin and galangin. The TEAC values of chrysin and galangin are comparable, whereas galangin appears to be a much better antioxidant in other assays. The relatively high TEAC values of chrysin and resorcinol are due to the ability of the reaction products, formed by the reaction of the parent compound with ABTS•, to further react with ABTS•. With catechol, hydroquinone and galangin, these reaction products do not react with ABTS• and therefore make no contribution to the TEAC. The possible contribution of reaction products to the TEAC of a compound hampers the use of the TEAC assay for constructing structure–activity relationships (SAR).
Weibao Kong - One of the best experts on this subject based on the ideXlab platform.
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evaluation of antioxidant activities and total phenolic contents of typical malting barley varieties
Food Chemistry, 2008Co-Authors: Haifeng Zhao, Wei Fan, Jianjun Dong, Jian Chen, Lianju Shan, Yan Lin, Weibao KongAbstract:Abstract Fourteen typical malting barley varieties from China were evaluated for their DPPH radical, ABTS radical cation and superoxide anion radical scavenging activities, reducing power, metal chelating activities, and total phenolic contents (TPC). All barley samples exhibited significant antioxidant activities determined by different assays, and contained significant levels of phenolic compounds. Gan4 and Wupi1 barley exhibited the highest DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power. Gan4 and Humai16 barley showed the highest TPC, whereas the highest superoxide anion radical scavenging activity and metal chelating activity were found in Huaimai19 and Ken3 barley, respectively. The Pearson correlation analysis revealed that the TPC showed strong correlations with DPPH radical scavenging activity, ABTS radical cation scavenging activity, and reducing power (P 0.05). Moreover, DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power were well positively correlated with each other (P
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evaluation of antioxidant activities and total phenolic contents of typical malting barley varieties
Food Chemistry, 2008Co-Authors: Haifeng Zhao, Jianjun Dong, Jian Chen, Lianju Shan, Jian Lu, Weibao KongAbstract:Fourteen typical malting barley varieties from China were evaluated for their DPPH radical, ABTS radical cation and superoxide anion radical scavenging activities, reducing power, metal chelating activities, and total phenolic contents (TPC). All barley samples exhibited significant antioxidant activities determined by different assays, and contained significant levels of phenolic compounds. Gan4 and Wupi1 barley exhibited the highest DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power. Gan4 and Humai16 barley showed the highest TPC, whereas the highest superoxide anion radical scavenging activity and metal chelating activity were found in Huaimai19 and Ken3 barley, respectively. The Pearson correlation analysis revealed that the TPC showed strong correlations with DPPH radical scavenging activity, ABTS radical cation scavenging activity, and reducing power (P 0.05). Moreover, DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power were well positively correlated with each other (P < 0.01). Principal component analysis (PCA) was applied to understand the interrelationships among the measured antioxidant activity evaluation indices, and to gain an overview of the similarities and differences among the 14 barley varieties.
Marie-josé S. J. Arts - One of the best experts on this subject based on the ideXlab platform.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
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a new approach to assess the total antioxidant capacity using the teac assay
Food Chemistry, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Sebastiaan J Dallinga, Aalt BastAbstract:Abstract The trolox equivalent antioxidant capacity (TEAC) assay is a popular method for assessing the capacity of a compound to scavenge ABTS radicals (ABTS ). Under the conditions in which the assay is performed, the reaction between most antioxidants and ABTS does not reach completion within the time span applied. This leads to an underestimation of the TEAC of these antioxidants. In the present study, incubations with different concentrations of ABTS and a fixed concentration of antioxidant were performed. The decrease in ABTS concentration in 6 min was plotted against the initial concentration of ABTS and fitted by an exponential function. Extrapolation of the fit to an infinite excess of ABTS gives the maximal concentration of ABTS that can be scavenged by the antioxidant at the concentration employed. This can be used to determine the actual TEAC of antioxidants, i.e. the total antioxidant capacity.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
H P Voss - One of the best experts on this subject based on the ideXlab platform.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
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a new approach to assess the total antioxidant capacity using the teac assay
Food Chemistry, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Sebastiaan J Dallinga, Aalt BastAbstract:Abstract The trolox equivalent antioxidant capacity (TEAC) assay is a popular method for assessing the capacity of a compound to scavenge ABTS radicals (ABTS ). Under the conditions in which the assay is performed, the reaction between most antioxidants and ABTS does not reach completion within the time span applied. This leads to an underestimation of the TEAC of these antioxidants. In the present study, incubations with different concentrations of ABTS and a fixed concentration of antioxidant were performed. The decrease in ABTS concentration in 6 min was plotted against the initial concentration of ABTS and fitted by an exponential function. Extrapolation of the fit to an infinite excess of ABTS gives the maximal concentration of ABTS that can be scavenged by the antioxidant at the concentration employed. This can be used to determine the actual TEAC of antioxidants, i.e. the total antioxidant capacity.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
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a critical appraisal of the use of the antioxidant capacity teac assay in defining optimal antioxidant structures
Food Chemistry, 2003Co-Authors: Mariken J T J Arts, H P Voss, Guido R.m.m. Haenen, Sebastiaan J Dallinga, Aalt BastAbstract:In the Trolox Equivalent Antioxidant Capacity (TEAC) assay, i.e. the capacity of a compound to scavenge the ABTS radical (ABTS•), is assessed. The aim of the present study is to evaluate the applicability of the TEAC assay to predict the antioxidant effectivity of a compound. For this purpose the TEAC assay is compared with other screening assays, such as superoxide scavenging, peroxynitrite scavenging and lipid peroxidation. Of the structurally related compounds, catechol, resorcinol and hydroquinone, resorcinol has the highest TEAC. In contrast, resorcinol appears to have a much lower antioxidant activity than catechol and hydroquinone in other in vitro assays. Similar discrepancies were observed with the flavonoids, chrysin and galangin. The TEAC values of chrysin and galangin are comparable, whereas galangin appears to be a much better antioxidant in other assays. The relatively high TEAC values of chrysin and resorcinol are due to the ability of the reaction products, formed by the reaction of the parent compound with ABTS•, to further react with ABTS•. With catechol, hydroquinone and galangin, these reaction products do not react with ABTS• and therefore make no contribution to the TEAC. The possible contribution of reaction products to the TEAC of a compound hampers the use of the TEAC assay for constructing structure–activity relationships (SAR).
Guido R.m.m. Haenen - One of the best experts on this subject based on the ideXlab platform.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
-
a new approach to assess the total antioxidant capacity using the teac assay
Food Chemistry, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Sebastiaan J Dallinga, Aalt BastAbstract:Abstract The trolox equivalent antioxidant capacity (TEAC) assay is a popular method for assessing the capacity of a compound to scavenge ABTS radicals (ABTS ). Under the conditions in which the assay is performed, the reaction between most antioxidants and ABTS does not reach completion within the time span applied. This leads to an underestimation of the TEAC of these antioxidants. In the present study, incubations with different concentrations of ABTS and a fixed concentration of antioxidant were performed. The decrease in ABTS concentration in 6 min was plotted against the initial concentration of ABTS and fitted by an exponential function. Extrapolation of the fit to an infinite excess of ABTS gives the maximal concentration of ABTS that can be scavenged by the antioxidant at the concentration employed. This can be used to determine the actual TEAC of antioxidants, i.e. the total antioxidant capacity.
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antioxidant capacity of reaction products limits the applicability of the trolox equivalent antioxidant capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher antioxidant capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the antioxidant capacity of the parent compound plus the potential antioxidant capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking antioxidants.
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a critical appraisal of the use of the antioxidant capacity teac assay in defining optimal antioxidant structures
Food Chemistry, 2003Co-Authors: Mariken J T J Arts, H P Voss, Guido R.m.m. Haenen, Sebastiaan J Dallinga, Aalt BastAbstract:In the Trolox Equivalent Antioxidant Capacity (TEAC) assay, i.e. the capacity of a compound to scavenge the ABTS radical (ABTS•), is assessed. The aim of the present study is to evaluate the applicability of the TEAC assay to predict the antioxidant effectivity of a compound. For this purpose the TEAC assay is compared with other screening assays, such as superoxide scavenging, peroxynitrite scavenging and lipid peroxidation. Of the structurally related compounds, catechol, resorcinol and hydroquinone, resorcinol has the highest TEAC. In contrast, resorcinol appears to have a much lower antioxidant activity than catechol and hydroquinone in other in vitro assays. Similar discrepancies were observed with the flavonoids, chrysin and galangin. The TEAC values of chrysin and galangin are comparable, whereas galangin appears to be a much better antioxidant in other assays. The relatively high TEAC values of chrysin and resorcinol are due to the ability of the reaction products, formed by the reaction of the parent compound with ABTS•, to further react with ABTS•. With catechol, hydroquinone and galangin, these reaction products do not react with ABTS• and therefore make no contribution to the TEAC. The possible contribution of reaction products to the TEAC of a compound hampers the use of the TEAC assay for constructing structure–activity relationships (SAR).
