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Ronald L. Prior - One of the best experts on this subject based on the ideXlab platform.
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standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Ronald L. Prior, Xianli Wu, Karen M SchaichAbstract: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 giv...
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high throughput Assay of oxygen radical absorbance capacity ORAC using a multichannel liquid handling system coupled with a microplate fluorescence reader in 96 well format
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Dejian Huang, Maureen Hampschwoodill, Judith A Flanagan, Ronald L. PriorAbstract:The oxygen radical absorbance capacity (ORAC) Assay has been widely accepted as a standard tool to measure the antioxidant activity in the nutraceutical, pharmaceutical, and food industries. However, the ORAC Assay has been criticized for a lack of accessibility due to the unavailability of the COBAS FARA II analyzer, an instrument discontinued by the manufacturer. In addition, the manual sample preparation is time-consuming and labor-intensive. The objective of this study was to develop a high-throughput instrument platform that can fully automate the ORAC Assay procedure. The new instrument platform consists of a robotic eight-channel liquid handling system and a microplate fluorescence reader. By using the high-throughput platform, the efficiency of the Assay is improved with at least a 10-fold increase in sample throughput over the current procedure. The mean of intra- and interday CVs was ≤15%, and the limit of detection and limit of quantitation were 5 and 6.25 μM, respectively. Keywords: ORAC; anti...
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development and validation of an improved oxygen radical absorbance capacity Assay using fluorescein as the fluorescent probe
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Maureen Hampschwoodill, Ronald L. PriorAbstract:An improved method of oxygen radical absorbance capacity (ORAC) Assay has been developed and validated using fluorescein (3‘,6‘-dihydroxyspiro[isobenzofuran-1[3H],9‘[9H]-xanthen]-3-one) as the fluorescent probe. Our results demonstrate that fluorescein (FL) is superior to B-phycoerythrin. The oxidized FL products induced by peroxyl radical were identified by LC/MS, and the reaction mechanism was determined to follow a classic hydrogen atom transfer mechanism. In addition, methodological and mechanistic comparison of ORACFL with other widely used methods was discussed. It is concluded that, unlike other popular methods, the improved ORACFL Assay provides a direct measure of hydrophilic chain-breaking antioxidant capacity against peroxyl radical. Keywords: Fluorescein; ORAC; TEAC; FRAP; chain-breaking antioxidant; free radical; hydrogen atom transfer; single electron transfer
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in vivo total antioxidant capacity comparison of different analytical methods
Free Radical Biology and Medicine, 1999Co-Authors: Ronald L. PriorAbstract:Abstract Several methods have been developed to measure the total antioxidant capacity of a biological sample. The use of peroxyl or hydroxyl radicals as pro-oxidants in the oxygen radical absorbance capacity (ORAC) Assay makes it different and unique from the Assays that involve oxidants that are not necessarily pro-oxidants. An improvement in quantitation is achieved in the ORAC Assay by taking the reaction between substrate and free radicals to completion and using an area-under-curve technique for quantitation compared to the Assays that measure a lag phase. The interpretation of the changes in plasma or serum antioxidant capacity becomes complicated by the different methods used in detecting these changes. The interpretation also depends upon the conditions under which the antioxidant capacity is determined because the measurement reflects outcomes in a dynamic system. An increased antioxidant capacity in plasma or serum may not necessarily be a desirable condition if it reflects a response to increased oxidative stress. Similarly, a decrease in plasma or serum antioxidant capacity may not necessarily be an undesirable condition if the measurement reflects decreased production of reactive species. Because of these complications, no single measurement of antioxidant status is going to be sufficient, but a “battery” of measurements, many of which will be described in Forum articles, will be necessary to adequately assess oxidative stress in biological systems.
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antioxidant capacity of oat avena sativa l extracts 1 inhibition of low density lipoprotein oxidation and oxygen radical absorbance capacity
Journal of Agricultural and Food Chemistry, 1999Co-Authors: Garry J Handelman, Ronald L. Prior, Mary F Walter, Zachary D Nightingale, Gregory L Paul, Jeffrey B BlumbergAbstract:Milled oat groat pearlings, trichomes, flour, and bran were extracted with methanol and the fractions tested in vitro for antioxidant capacity against low-density lipoprotein (LDL) oxidation and R-phycoerythrin protein oxidation in the oxygen radical absorbance capacity (ORAC) Assay. The oxidative reactions were generated by 2,2‘-azobis(2-amidinopropane) HCl (AAPH) or Cu2+ in the LDL Assay and by AAPH or Cu2+ + H2O2 in the ORAC Assay and calibrated against a Trolox standard to calculate Trolox equivalents (1 Trolox equivalent = 1 TE = activity of 1 μmol of Trolox). The antioxidant capacity of the oat fractions was generally consistent with a potency rank of pearlings (2.89−8.58 TE/g) > flour (1.00−3.54 TE/g) > trichome (1.74 TE/g) = bran (1.02−1.62 TE/g) in both LDL and ORAC Assays regardless of the free radical generator employed. A portion of the oat antioxidant constituents may be heat labile as the greatest activity was found among non-steam-treated pearlings. The contribution of oat tocols from the f...
Nicki J Engeseth - One of the best experts on this subject based on the ideXlab platform.
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antioxidant capacity of honeys from various floral sources based on the determination of oxygen radical absorbance capacity and inhibition of in vitro lipoprotein oxidation in human serum samples
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Nele Gheldof, Nicki J EngesethAbstract:Honeys from seven different floral sources were analyzed for in vitro antioxidant capacity and total phenolic content. Antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) Assay and by monitoring the formation of conjugated dienes as an index of the inhibition of copper-catalyzed serum lipoprotein oxidation. ORAC values ranged from 3.1 to 16.3 micromol Trolox equivalent/g honey. The darkest colored honeys, such as buckwheat honey, had the highest ORAC values. A linear correlation was observed between phenolic content and ORAC activity of the investigated honeys (p < 0.0001, R (2) = 0.9497). The relationship between the ORAC activity and inhibition of lipoprotein oxidation by the honeys yielded a correlation coefficient of 0.6653 (p = 0.0136). This work shows that honey may be used as a healthy alternative to sugar in many products and thereby serve as a source of dietary antioxidants.
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antioxidant capacity of honeys from various floral sources based on the determination of oxygen radical absorbance capacity and inhibition of in vitro lipoprotein oxidation in human serum samples
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Nele Gheldof, Nicki J EngesethAbstract:Honeys from seven different floral sources were analyzed for in vitro antioxidant capacity and total phenolic content. Antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) Assay and by monitoring the formation of conjugated dienes as an index of the inhibition of copper-catalyzed serum lipoprotein oxidation. ORAC values ranged from 3.1 to 16.3 μmol Trolox equivalent/g honey. The darkest colored honeys, such as buckwheat honey, had the highest ORAC values. A linear correlation was observed between phenolic content and ORAC activity of the investigated honeys (p < 0.0001, R 2 = 0.9497). The relationship between the ORAC activity and inhibition of lipoprotein oxidation by the honeys yielded a correlation coefficient of 0.6653 (p = 0.0136). This work shows that honey may be used as a healthy alternative to sugar in many products and thereby serve as a source of dietary antioxidants. Keywords: Honey; antioxidants; lipoprotein oxidation; phenolics
Afshin Babazadeh - One of the best experts on this subject based on the ideXlab platform.
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development of new ultrasonic solvent assisted method for determination of trans resveratrol from red grapes optimization characterization and antioxidant activity ORAC Assay
Food bioscience, 2017Co-Authors: Afshin Babazadeh, Arezou Taghvimi, Hamed Hamishehkar, Mahnaz TabibiazarAbstract:Abstract This work was aimed at developing an ultrasonic-assisted extraction of trans-resveratrol from red grape wastes using a new combination of solvents and response surface method- Box–Behnken design. The experiment was carried out on the industrial waste, skin, and pulp parts of 18 different types of Iranian red grapes. Ultrasound-assisted solvent extraction was carried out using different ratios of ethanol:polyethylene glycol (PEG):water (v/v), ultrasonication time, and temperature. The optimized conditions were achieved as a combination of 19.4 min, 53.6 °C, and 48:32:20 (v/v), which remarkably improved the extraction of trans-resveratrol content. The presence of PEG in the extraction medium enhanced the extraction efficiency by 39.48%. Reverse phase high performance liquid chromatography ultra-violent (RP-HPLC-UV) was applied for the quantification. The amounts of trans-resveratrol varied between 68.36 ± 3.06 and 862 ± 4.67 µg/g-dry material of the initial samples based on optimized conditions. Retention time of trans-resveratrol was obtained in less than 5 min, which indicates the high accuracy of developed HPLC method. There was a significant relationship between the amount of resveratrol and antioxidant activity. Antioxidant activity of samples extracted by optimized method was about four times higher than conventional method (80:20 ethanol:water (v/v), 30 min sonication, and 60 °C temperature) measured by oxygen radical absorbance capacity (ORAC) Assay. This research provided food grade extraction method due to reduction in the use of ethanol in extraction process. Furthermore, the results can provide a new HPLC elution method for easy and fast detection and quantification of trans-resveratrol in industrial scale.
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Development of new ultrasonic–solvent assisted method for determination of trans-resveratrol from red grapes: optimization, characterization, and antioxidant activity (ORAC Assay)
Food Bioscience, 2017Co-Authors: Afshin Babazadeh, Arezou Taghvimi, Hamed Hamishehkar, Mahnaz TabibiazarAbstract:Abstract This work was aimed at developing an ultrasonic-assisted extraction of trans-resveratrol from red grape wastes using a new combination of solvents and response surface method- Box–Behnken design. The experiment was carried out on the industrial waste, skin, and pulp parts of 18 different types of Iranian red grapes. Ultrasound-assisted solvent extraction was carried out using different ratios of ethanol:polyethylene glycol (PEG):water (v/v), ultrasonication time, and temperature. The optimized conditions were achieved as a combination of 19.4 min, 53.6 °C, and 48:32:20 (v/v), which remarkably improved the extraction of trans-resveratrol content. The presence of PEG in the extraction medium enhanced the extraction efficiency by 39.48%. Reverse phase high performance liquid chromatography ultra-violent (RP-HPLC-UV) was applied for the quantification. The amounts of trans-resveratrol varied between 68.36 ± 3.06 and 862 ± 4.67 µg/g-dry material of the initial samples based on optimized conditions. Retention time of trans-resveratrol was obtained in less than 5 min, which indicates the high accuracy of developed HPLC method. There was a significant relationship between the amount of resveratrol and antioxidant activity. Antioxidant activity of samples extracted by optimized method was about four times higher than conventional method (80:20 ethanol:water (v/v), 30 min sonication, and 60 °C temperature) measured by oxygen radical absorbance capacity (ORAC) Assay. This research provided food grade extraction method due to reduction in the use of ethanol in extraction process. Furthermore, the results can provide a new HPLC elution method for easy and fast detection and quantification of trans-resveratrol in industrial scale.
Mahnaz Tabibiazar - One of the best experts on this subject based on the ideXlab platform.
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development of new ultrasonic solvent assisted method for determination of trans resveratrol from red grapes optimization characterization and antioxidant activity ORAC Assay
Food bioscience, 2017Co-Authors: Afshin Babazadeh, Arezou Taghvimi, Hamed Hamishehkar, Mahnaz TabibiazarAbstract:Abstract This work was aimed at developing an ultrasonic-assisted extraction of trans-resveratrol from red grape wastes using a new combination of solvents and response surface method- Box–Behnken design. The experiment was carried out on the industrial waste, skin, and pulp parts of 18 different types of Iranian red grapes. Ultrasound-assisted solvent extraction was carried out using different ratios of ethanol:polyethylene glycol (PEG):water (v/v), ultrasonication time, and temperature. The optimized conditions were achieved as a combination of 19.4 min, 53.6 °C, and 48:32:20 (v/v), which remarkably improved the extraction of trans-resveratrol content. The presence of PEG in the extraction medium enhanced the extraction efficiency by 39.48%. Reverse phase high performance liquid chromatography ultra-violent (RP-HPLC-UV) was applied for the quantification. The amounts of trans-resveratrol varied between 68.36 ± 3.06 and 862 ± 4.67 µg/g-dry material of the initial samples based on optimized conditions. Retention time of trans-resveratrol was obtained in less than 5 min, which indicates the high accuracy of developed HPLC method. There was a significant relationship between the amount of resveratrol and antioxidant activity. Antioxidant activity of samples extracted by optimized method was about four times higher than conventional method (80:20 ethanol:water (v/v), 30 min sonication, and 60 °C temperature) measured by oxygen radical absorbance capacity (ORAC) Assay. This research provided food grade extraction method due to reduction in the use of ethanol in extraction process. Furthermore, the results can provide a new HPLC elution method for easy and fast detection and quantification of trans-resveratrol in industrial scale.
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Development of new ultrasonic–solvent assisted method for determination of trans-resveratrol from red grapes: optimization, characterization, and antioxidant activity (ORAC Assay)
Food Bioscience, 2017Co-Authors: Afshin Babazadeh, Arezou Taghvimi, Hamed Hamishehkar, Mahnaz TabibiazarAbstract:Abstract This work was aimed at developing an ultrasonic-assisted extraction of trans-resveratrol from red grape wastes using a new combination of solvents and response surface method- Box–Behnken design. The experiment was carried out on the industrial waste, skin, and pulp parts of 18 different types of Iranian red grapes. Ultrasound-assisted solvent extraction was carried out using different ratios of ethanol:polyethylene glycol (PEG):water (v/v), ultrasonication time, and temperature. The optimized conditions were achieved as a combination of 19.4 min, 53.6 °C, and 48:32:20 (v/v), which remarkably improved the extraction of trans-resveratrol content. The presence of PEG in the extraction medium enhanced the extraction efficiency by 39.48%. Reverse phase high performance liquid chromatography ultra-violent (RP-HPLC-UV) was applied for the quantification. The amounts of trans-resveratrol varied between 68.36 ± 3.06 and 862 ± 4.67 µg/g-dry material of the initial samples based on optimized conditions. Retention time of trans-resveratrol was obtained in less than 5 min, which indicates the high accuracy of developed HPLC method. There was a significant relationship between the amount of resveratrol and antioxidant activity. Antioxidant activity of samples extracted by optimized method was about four times higher than conventional method (80:20 ethanol:water (v/v), 30 min sonication, and 60 °C temperature) measured by oxygen radical absorbance capacity (ORAC) Assay. This research provided food grade extraction method due to reduction in the use of ethanol in extraction process. Furthermore, the results can provide a new HPLC elution method for easy and fast detection and quantification of trans-resveratrol in industrial scale.
Nele Gheldof - One of the best experts on this subject based on the ideXlab platform.
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antioxidant capacity of honeys from various floral sources based on the determination of oxygen radical absorbance capacity and inhibition of in vitro lipoprotein oxidation in human serum samples
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Nele Gheldof, Nicki J EngesethAbstract:Honeys from seven different floral sources were analyzed for in vitro antioxidant capacity and total phenolic content. Antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) Assay and by monitoring the formation of conjugated dienes as an index of the inhibition of copper-catalyzed serum lipoprotein oxidation. ORAC values ranged from 3.1 to 16.3 micromol Trolox equivalent/g honey. The darkest colored honeys, such as buckwheat honey, had the highest ORAC values. A linear correlation was observed between phenolic content and ORAC activity of the investigated honeys (p < 0.0001, R (2) = 0.9497). The relationship between the ORAC activity and inhibition of lipoprotein oxidation by the honeys yielded a correlation coefficient of 0.6653 (p = 0.0136). This work shows that honey may be used as a healthy alternative to sugar in many products and thereby serve as a source of dietary antioxidants.
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antioxidant capacity of honeys from various floral sources based on the determination of oxygen radical absorbance capacity and inhibition of in vitro lipoprotein oxidation in human serum samples
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Nele Gheldof, Nicki J EngesethAbstract:Honeys from seven different floral sources were analyzed for in vitro antioxidant capacity and total phenolic content. Antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) Assay and by monitoring the formation of conjugated dienes as an index of the inhibition of copper-catalyzed serum lipoprotein oxidation. ORAC values ranged from 3.1 to 16.3 μmol Trolox equivalent/g honey. The darkest colored honeys, such as buckwheat honey, had the highest ORAC values. A linear correlation was observed between phenolic content and ORAC activity of the investigated honeys (p < 0.0001, R 2 = 0.9497). The relationship between the ORAC activity and inhibition of lipoprotein oxidation by the honeys yielded a correlation coefficient of 0.6653 (p = 0.0136). This work shows that honey may be used as a healthy alternative to sugar in many products and thereby serve as a source of dietary antioxidants. Keywords: Honey; antioxidants; lipoprotein oxidation; phenolics