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Measurement of xanthine oxidase inhibition activity of phenolics and flavonoids with a modified cupric reducing antioxidant capacity (CUPRAC) method.
Anal Chim Acta. 2009 Mar 16; 636(1):42-50.AC

Abstract

Various dietary polyphenolics have been found to show an inhibitory effect on xanthine oxidase (XO) which mediates oxidative stress-originated diseases because of its ability to generate reactive oxygen species (ROS), including superoxide anion radical (O(2)(-)) and hydrogen peroxide. XO activity has usually been determined by following the rate of uric acid formation from xanthine-xanthine oxidase (X-XO) system using the classical XO activity assay (UV-method) at 295nm. Since some polyphenolics have strong absorption from the UV to visible region, XO-inhibitory activity of polyphenolics was alternatively determined without interference by directly measuring the formation of uric acid and hydrogen peroxide using the modified CUPRAC (cupric reducing antioxidant capacity) spectrophotometric method at 450nm. The CUPRAC absorbance of the incubation solution due to the reduction of Cu(II)-neocuproine reagent by the products of the X-XO system decreased in the presence of polyphenolics, the difference being proportional to the XO inhibition ability of the tested compound. The structure-activity relationship revealed that the flavones and flavonols with a 7-hydroxyl group such as apigenin, luteolin, kaempferol, quercetin, and myricetin inhibited XO-inhibitory activity at low concentrations (IC(50) values from 1.46 to 1.90microM), while the flavan-3-ols and naringin were less inhibitory. The findings of the developed method for quercetin and catechin in the presence of catalase were statistically alike with those of HPLC. In addition to polyphenolics, five kinds of herbs were evaluated for their XO-inhibitory activity using the developed method. The proposed spectrophotometric method was practical, low-cost, rapid, and could reliably assay uric acid and hydrogen peroxide in the presence of polyphenols (flavonoids, simple phenolic acids and hydroxycinnamic acids), and less open to interferences by UV-absorbing substances.

Authors+Show Affiliations

Department of Chemistry, Faculty of Engineering, Istanbul University, Avcilar, 34320, Istanbul, Turkey.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

19231354

Citation

Ozyürek, Mustafa, et al. "Measurement of Xanthine Oxidase Inhibition Activity of Phenolics and Flavonoids With a Modified Cupric Reducing Antioxidant Capacity (CUPRAC) Method." Analytica Chimica Acta, vol. 636, no. 1, 2009, pp. 42-50.
Ozyürek M, Bektaşoğlu B, Güçlü K, et al. Measurement of xanthine oxidase inhibition activity of phenolics and flavonoids with a modified cupric reducing antioxidant capacity (CUPRAC) method. Anal Chim Acta. 2009;636(1):42-50.
Ozyürek, M., Bektaşoğlu, B., Güçlü, K., & Apak, R. (2009). Measurement of xanthine oxidase inhibition activity of phenolics and flavonoids with a modified cupric reducing antioxidant capacity (CUPRAC) method. Analytica Chimica Acta, 636(1), 42-50. https://doi.org/10.1016/j.aca.2009.01.037
Ozyürek M, et al. Measurement of Xanthine Oxidase Inhibition Activity of Phenolics and Flavonoids With a Modified Cupric Reducing Antioxidant Capacity (CUPRAC) Method. Anal Chim Acta. 2009 Mar 16;636(1):42-50. PubMed PMID: 19231354.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Measurement of xanthine oxidase inhibition activity of phenolics and flavonoids with a modified cupric reducing antioxidant capacity (CUPRAC) method. AU - Ozyürek,Mustafa, AU - Bektaşoğlu,Burcu, AU - Güçlü,Kubilay, AU - Apak,Reşat, Y1 - 2009/01/22/ PY - 2008/11/27/received PY - 2009/01/12/revised PY - 2009/01/15/accepted PY - 2009/2/24/entrez PY - 2009/2/24/pubmed PY - 2009/4/29/medline SP - 42 EP - 50 JF - Analytica chimica acta JO - Anal. Chim. Acta VL - 636 IS - 1 N2 - Various dietary polyphenolics have been found to show an inhibitory effect on xanthine oxidase (XO) which mediates oxidative stress-originated diseases because of its ability to generate reactive oxygen species (ROS), including superoxide anion radical (O(2)(-)) and hydrogen peroxide. XO activity has usually been determined by following the rate of uric acid formation from xanthine-xanthine oxidase (X-XO) system using the classical XO activity assay (UV-method) at 295nm. Since some polyphenolics have strong absorption from the UV to visible region, XO-inhibitory activity of polyphenolics was alternatively determined without interference by directly measuring the formation of uric acid and hydrogen peroxide using the modified CUPRAC (cupric reducing antioxidant capacity) spectrophotometric method at 450nm. The CUPRAC absorbance of the incubation solution due to the reduction of Cu(II)-neocuproine reagent by the products of the X-XO system decreased in the presence of polyphenolics, the difference being proportional to the XO inhibition ability of the tested compound. The structure-activity relationship revealed that the flavones and flavonols with a 7-hydroxyl group such as apigenin, luteolin, kaempferol, quercetin, and myricetin inhibited XO-inhibitory activity at low concentrations (IC(50) values from 1.46 to 1.90microM), while the flavan-3-ols and naringin were less inhibitory. The findings of the developed method for quercetin and catechin in the presence of catalase were statistically alike with those of HPLC. In addition to polyphenolics, five kinds of herbs were evaluated for their XO-inhibitory activity using the developed method. The proposed spectrophotometric method was practical, low-cost, rapid, and could reliably assay uric acid and hydrogen peroxide in the presence of polyphenols (flavonoids, simple phenolic acids and hydroxycinnamic acids), and less open to interferences by UV-absorbing substances. SN - 1873-4324 UR - https://www.unboundmedicine.com/medline/citation/19231354/Measurement_of_xanthine_oxidase_inhibition_activity_of_phenolics_and_flavonoids_with_a_modified_cupric_reducing_antioxidant_capacity__CUPRAC__method_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0003-2670(09)00108-1 DB - PRIME DP - Unbound Medicine ER -