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Resat Apak - One of the best experts on this subject based on the ideXlab platform.
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comparison of total antioxidant capacity and phenolic compositIon of some apple juices with combined hplc cuprac assay
Food Chemistry, 2010Co-Authors: şeyda Karaman, Esma Tutem, Kevser Sozgen Baskan, Resat ApakAbstract:Abstract It was aimed in this study to identify and quantify various constituents (particularly phenolics) of apple juice and to quantitatively compare the total antioxidant capacities of juices obtained from apple varieties grown in Turkey. Experimental studies were performed by determining the total antioxidant capacities using two spectrophotometric methods, Cupric Ion reducing antioxidant capacity (CUPRAC) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonate) (ABTS) methods, and by identificatIon and quantificatIon of the leading antioxidant constituents individually with HPLC. The total antioxidant capacity (TAC) values of HPLC-quantified antioxidant constituents were found, and compared with those found by CUPRAC and ABTS. The TAC of HPLC-quantified compounds accounted for between 40.0% and 70.6% of the observed CUPRAC capacities of apple juices with respect to apple varieties. The order of antioxidant capacity of apple juices determined by the CUPRAC and ABTS methods were: Ervin Spur > King Luscious > Sky Spur > Amasya > Arap Kizi ⩾ Granny Smith > Lutz Golden.
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Cupric Ion reducing antioxidant capacity assay for antioxidants in human serum and for hydroxyl radical scavengers
Methods of Molecular Biology, 2010Co-Authors: Resat Apak, Mustafa Ozyurek, Kubilay Guclu, Burcu Bektasoglu, Mustafa BenerAbstract:Tests measuring the combined antioxidant effect of the nonenzymatic defenses in biological fluids may be useful in providing an index of the organism's capability to counteract reactive species known as pro-oxidants, resist oxidative damage, and combat oxidative stress-related diseases. The selected chromogenic redox reagent for the assay of human serum should be easily accessible, stable, selective, and respond to all types of biologically important antioxidants such as ascorbic acid, alpha-tocopherol, beta-carotene, reduced glutathIone (GSH), uric acid, and bilirubin, regardless of chemical type or hydrophilicity. Our recently developed Cupric reducing antioxidant capacity (CUPRAC) spectrophotometric method for a number of polyphenols and flavonoids using the copper(II)-neocuproine reagent in ammonium acetate buffer is now applied to a complete series of plasma antioxidants for the assay of total antioxidant capacity of serum, and the resulting absorbance at 450 nm is recorded either directly (e.g., for ascorbic acid, alpha-tocopherol, and glutathIone) or after incubatIon at 50 degrees C for 20 min (e.g., for uric acid, bilirubin, and albumin), quantitatIon being made by means of a calibratIon curve. The lipophilic antioxidants, alpha-tocopherol and beta-carotene, are assayed in dichloromethane. Lipophilic antioxidants of serum are extracted with n-hexane from an ethanolic solutIon of serum subjected to centrifugatIon. Hydrophilic antioxidants of serum are assayed in the centrifugate after perchloric acid precipitatIon of proteins. The CUPRAC molar absorptivities, linear ranges, and TEAC (trolox equivalent antioxidant capacity) coefficients of the serum antioxidants are established, and the results are evaluated in comparison with the findings of the ABTS/TEAC reference method. The intra- and inter-assay coefficients of variatIon (CVs) are 0.7 and 1.5%, respectively, for serum. The CUPRAC assay proved to be efficient for glutathIone and thiol-type antioxidants, for which the FRAP (ferric reducing antioxidant potency) test is basically nonresponsive. The additivity of absorbances of all the tested antioxidants confirmed that antioxidants in the CUPRAC test do not chemically interact among each other so as to cause an intensificatIon or quenching of the theoretically expected absorbance, and that a total antioxidant capacity (TAC) assay of serum is possible. As a distinct advantage over other electron-transfer based assays (e.g., Folin, FRAP, ABTS, DPPH), CUPRAC is superior in regard to its realistic pH close to the physiological pH, favorable redox potential, accessibility and stability of reagents, and applicability to lipophilic antioxidants as well as hydrophilic ones. The CUPRAC procedure can also assay hydroxyl radicals, being the most reactive oxygen species (ROS). As a more convenient, efficient, and less costly alternative to HPLC/electrochemical detectIon techniques and to the nonspecific, low-yield TBARS test, we use p-aminobenzoate, 2,4- and 3,5-dimethoxybenzoate probes for detecting hydroxyl radicals generated from an equivalent mixture of [Fe(II)+EDTA] with hydrogen peroxide. The produced hydroxyl radicals attack both the probe and the water-soluble antioxidants in 37 degrees C-incubated solutIons for 2 h. The CUPRAC absorbance of the ethylacetate extract due to the reductIon of Cu(II)-neocuproine reagent by the hydroxylated probe decreases in the presence of (.)OH scavengers, the difference being proportIonal to the scavenging ability of the tested compound. The developed method is less lengthy, more specific, and of a higher yield than the classical TBARS assay.
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combined hplc cuprac Cupric Ion reducing antioxidant capacity assay of parsley celery leaves and nettle
Talanta, 2008Co-Authors: Leyla Yildiz, Kevser Sozgen Baskan, Esma Tutem, Resat ApakAbstract:Abstract This study aims to identify the essential antioxidant compounds present in parsley (Petroselinum sativum) and celery (Apium graveolens) leaves belonging to the Umbelliferae (Apiaceae) family, and in stinging nettle (Urtica dioica) belonging to Urticaceae family, to measure the total antioxidant capacity (TAC) of these compounds with CUPRAC (Cupric Ion reducing antioxidant capacity) and ABTS spectrophotometric methods, and to correlate the TAC with high performance liquid chromatography (HPLC) findings. The CUPRAC spectrophotometric method of TAC assay using copper(II)-neocuproine (2,9-dimethyl-1,10-phenanthroline) as the chromogenic oxidant was developed in our laboratories. The individual antioxidant constituents of plant extracts were identified and quantified by HPLC on a C18 column using a modified mobile phase of gradient elutIon comprised of MeOH–0.2% o-phosphoric acid and UV detectIon for polyphenols at 280 nm. The TAC values of HPLC-quantified antioxidant constituents were found, and compared for the first time with those found by CUPRAC. The TAC of HPLC-quantified compounds accounted for a relatively high percentage of the observed CUPRAC capacities of plant extracts, namely 81% of nettle, 60–77% of parsley (in different hydrolyzates of extract and solid sample), and 41–57% of celery leaves (in different hydrolyzates). The CUPRAC total capacities of the 70% MeOH extracts of studied plants (in the units of mmol trolox g−1 plant) were in the order: celery leaves > nettle > parsley. The TAC calculated with the aid of HPLC-spectrophotometry did not compensate for 100% of the CUPRAC total capacities, because all flavonoid glycosides subjected to hydrolysis were either not detectable with HPLC, or not converted to the corresponding aglycons (i.e., easily detectable and quantifiable with HPLC) during the hydrolysis step.
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Cupric Ion reducing antioxidant capacity assay for food antioxidants vitamins polyphenolics and flavonoids in food extracts
Methods of Molecular Biology, 2008Co-Authors: Resat Apak, Mustafa Ozyurek, Burcu Bektas Oglu, Kubilay Guclu, Mustafa BenerAbstract:: Antioxidants are health beneficial compounds through their combat with reactive oxygen and nitrogen species and free radicals that may cause tissue damage leading to various diseases. This work reports the development of a simple and widely applicable antioxidant capacity index for dietary polyphenols, vitamins C and E, and plasma antioxidants utilizing the copper(II)-neocuproine (Cu(II)-Nc) reagent as the chromogenic oxidizing agent. This novel method based on an electron-transfer mechanism was named by our research group as 'Cupric reducing antioxidant capacity', abbreviated as the CUPRAC method. The method is comprised of mixing the antioxidant solutIon with aqueous copper(II) chloride, alcoholic neocuproine, and ammonium acetate aqueous buffer at pH 7, and subsequently measuring the developed absorbance at 450 nm after 30 min. Since the color development is fast for compounds like ascorbic acid, gallic acid, and quercetin but slow for naringin and naringenin, the latter compounds are assayed after incubatIon at 50 degrees C on a water bath for 20 min. The flavonoid glycosides are hydrolyzed to their corresponding aglycones by refluxing in 1.2 M: HCl-containing 50% MeOH so as to exert maximal reducing power towards Cu(II)-Nc. The CUPRAC antioxidant capacities of synthetic mixtures are equal to the sum of individual capacities of antioxidant constituents, indicating lack of chemical deviatIons from Beer's law. Tests on antioxidant polyphenols demonstrate that the highest CUPRAC capacities are observed for epicatechin gallate, epigallocatechin gallate, quercetin, fisetin, epigallocatechin, catechin, and caffeic acid in this order, in accord with the number and positIon of the -OH groups as well the conjugatIon level of the molecule. The parallelism of the linear calibratIon curves of pure antioxidants in water and in a given complex matrix (plant extract) demonstrates that there are no chemical interactIons of interferent nature among the solutIon constituents, and that the antioxidant capacities of the tested antioxidants are additive, in conformity to the Beer's law. For individual determinatIon of ascorbic acid in fruit juices with a modified CUPRAC procedure, flavonoids are pre-extracted as their La(III) complexes prior to assay. For apricot extracts, a modified versIon of the CUPRAC assay based on anIon exchange separatIon at pH 3 is applied, since sulfited-dried sample extracts contain the hydrosulfite anIon interfering with the determinatIon. For herbal tea infusIons, the standard CUPRAC protocol is applied. The CUPRAC reagent is stable, easily accessible, low-cost, and is sensitive toward thiol-type antioxidants unlike FRAP. The reactIon is carried out at nearly physiological pH as opposed to the acidic pH of FRAP or to the alkaline pH of Folin methods, constituting a basic advantage for the realistic assay of biological fluids.
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the Cupric Ion reducing antioxidant capacity and polyphenolic content of some herbal teas
International Journal of Food Sciences and Nutrition, 2006Co-Authors: Resat Apak, Mustafa Ozyurek, Kubilay Guclu, Saliha Esin Karademir, Erol ErcagAbstract:The total antioxidant capacity of the aqueous extracts of some endemic herbs—prepared as infusIons by steeping these herbs in hot water—was assayed with bis(neocuproine)copper(II) chloride, also known as the Cupric Ion reducing antioxidant capacity (CUPRAC) reagent, which was easily accessible, rapid, stable and responsive to both hydrophilic and lipophilic antioxidants. The highest antioxidant capacities of some herbal teas available in the Turkish market were observed for scarlet pimpernel (Anagallis arvensis), sweet basil (Ocimum basilicum), green tea (Camellia sinensis) and lemon balm (Melissa officinalis), in this order (1.63, 1.18, 1.07, and 0.99 mmol trolox equivalent (TR)/g, respectively). For infusIons prepared from ready-to-use tea bags, the CUPRAC values were highest for Ceylon blended ordinary tea (4.41), green tea with lemon (1.61), English breakfast ordinary tea (1.26) and green tea (0.94), all of which were manufactured types of C. sinensis. Following the strongest antioxidant herbs with ca...
Omer Kilic - One of the best experts on this subject based on the ideXlab platform.
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evaluatIon of antioxidant capacity of endemic plant marrubium astracanicum subsp macrodon identificatIon of its phenolic contents by using hplc ms ms
Natural Product Research, 2019Co-Authors: Ercan Bursal, Abdulmelik Aras, Omer KilicAbstract:AbstractAntioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both Cupric Ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the compositIon and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentratIons of quinic acid, p-coumaric acid and malic acid were determined.
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evaluatIon of antioxidant capacity of endemic plant marrubium astracanicum subsp macrodon identificatIon of its phenolic contents by using hplc ms ms
Natural Product Research, 2019Co-Authors: Ercan Bursal, Abdulmelik Aras, Omer KilicAbstract:AbstractAntioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both Cupric Ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the compositIon and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentratIons of quinic acid, p-coumaric acid and malic acid were determined.
Ercan Bursal - One of the best experts on this subject based on the ideXlab platform.
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evaluatIon of antioxidant capacity of endemic plant marrubium astracanicum subsp macrodon identificatIon of its phenolic contents by using hplc ms ms
Natural Product Research, 2019Co-Authors: Ercan Bursal, Abdulmelik Aras, Omer KilicAbstract:AbstractAntioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both Cupric Ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the compositIon and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentratIons of quinic acid, p-coumaric acid and malic acid were determined.
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evaluatIon of antioxidant capacity of endemic plant marrubium astracanicum subsp macrodon identificatIon of its phenolic contents by using hplc ms ms
Natural Product Research, 2019Co-Authors: Ercan Bursal, Abdulmelik Aras, Omer KilicAbstract:AbstractAntioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both Cupric Ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the compositIon and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentratIons of quinic acid, p-coumaric acid and malic acid were determined.
Munadiah Munadiah - One of the best experts on this subject based on the ideXlab platform.
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PENENTUAN KADAR FLAVONOID DAN KAPASITAS ANTIOKSIDAN EKSTRAK ETANOL KULIT BATANG KELOR (Moringa oleifera L) DENGAN METODE DPPH, CUPRAC DAN FRAP
'Universitas Islam Negeri Alauddin Makassar', 2018Co-Authors: Haeria Haeria, Tahar Nurshalati, Munadiah MunadiahAbstract:Tumbuhan kelor (Moringa oleifera L.) sering disebut “miracle tree” dikarenakan semua bagian tumbuhan kelor sangat bermanfaat bagi kehidupan masyarakat. mulai dari daun, kulit batang, biji hingga akarnya, tumbuhan ini sudah dikenal luas sebagai tumbuhan obat. Kulit batang kelor (Moringa oleifera L.) mengandung senyawa steroid, flavonoid, alkaloid, fenolat, dan tanin. Penelitian ini bertujuan untuk mengetahui kadar flavonoid dan kapasitas antioksidan dari kulit batang kelor (Moringa oleifera). Pengukuran kapasitas antioksidan dilakukan menggunakan 3 metode yaitu CUPRAC (Cupric Ion reducing antioxidant capacity), DPPH (1,1difenil-1-pikrilhidrazil), dan FRAP (ferric reducing antioxidant power). Hasil penelitian membuktikan bahwa ekstrak etanol kulit batang kelor (Moringa oleifera) mengandung kadar flavonoid sebesar 20,17 mg QE/g Ekstrak dan untuk kapasitas antioksidan dengan metode DPPH yaitu 20,97 mg Tr/g Ekstrak, metode CUPRAC didapatkan hasil 4,82 mg Tr/g Ekstrak dan metode FRAP yaitu 2,49 mg Tr/g Ekstrak
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Penetapan Kadar Flavonoid dan Kapasitas Antioksidan Ekstrak Etanol Kulit Batang Kelor (Moringa oleifera) dengan Metode DPPH, CUPRAC, FRAP
2017Co-Authors: Munadiah MunadiahAbstract:Tumbuhan kelor (Moringa oleifera L.) sering disebut “miracle tree” dikarenakan semua bagian tumbuhan kelor sangat bermanfaat bagi kehidupan masyarakat. mulai dari daun, kulit batang, biji hingga akarnya, tumbuhan ini sudah dikenal luas sebagai tumbuhan obat. Kulit batang kelor (Moringa oleifera L.) mengandung senyawa steroid, flavonoid, alkaloid, fenolat, dan tanin. Penelitian ini bertujuan untuk mengetahui kadar flavonoid dan kapasitas antioksidan dari kulit batang kelor (Moringa oleifera). Pengukuran kapasitas antioksidan dilakukan menggunakan 3 metode yaitu CUPRAC (Cupric Ion reducing antioxidant capacity), DPPH (1,1-difenil-1-pikrilhidrazil), dan FRAP (ferric reducing antioxidant power). Hasil penelitian membuktikan bahwa ekstrak etanol kulit batang kelor (Moringa oleifera) mengandung kadar flavonoid sebesar 20,17 mg QE/g Ekstrak dan untuk kapasitas antioksidan dengan metode DPPH yaitu 20,97 mg Tr/g Ekstrak, metode CUPRAC didapatkan hasil 4,82 mg Tr/g Ekstrak dan metode FRAP yaitu 2,49 mg Tr/g Ekstrak
Abdulmelik Aras - One of the best experts on this subject based on the ideXlab platform.
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evaluatIon of antioxidant capacity of endemic plant marrubium astracanicum subsp macrodon identificatIon of its phenolic contents by using hplc ms ms
Natural Product Research, 2019Co-Authors: Ercan Bursal, Abdulmelik Aras, Omer KilicAbstract:AbstractAntioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both Cupric Ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the compositIon and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentratIons of quinic acid, p-coumaric acid and malic acid were determined.
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evaluatIon of antioxidant capacity of endemic plant marrubium astracanicum subsp macrodon identificatIon of its phenolic contents by using hplc ms ms
Natural Product Research, 2019Co-Authors: Ercan Bursal, Abdulmelik Aras, Omer KilicAbstract:AbstractAntioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both Cupric Ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the compositIon and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentratIons of quinic acid, p-coumaric acid and malic acid were determined.
