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ORAC and DPPH assay comparison to assess antioxidant capacity of tea infusions: relationship between total polyphenol and individual catechin content.
Int J Food Sci Nutr. 2010 Mar; 61(2):109-24.IJ

Abstract

Commercially available tea infusions are the major source of catechins for preparing bottled tea beverages and tea supplements available in the market today. In the present study, we analyzed five tea infusions to measure the total antioxidant capacity (TAC) by oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (DRSC) assays, total polyphenol content by the colorimetric method and individual catechin content by high-performance liquid chromatography. Four major tea catechins were also analyzed for their TAC to reveal differential antioxidant behavior of the tea infusions, resulting in the ORAC and DRSC methods. The correlation coefficients between DRSC and the total polyphenol or total catechin content of the tea infusions were 1.0 and 0.99. However, the values fall to 0.73 and 0.69, respectively, while the ORAC activity was correlated with total polyphenol and total catechin content. Determining the TAC of individual tea catechins showed that ORAC of epicatechin was seven-fold higher than that of epigallocatechin gallate; on the contrary, epigallocatechin gallate showed significantly (P < 0.05) stronger DRSC activity than epicatechin. By evaluating the structure-activity relationship, this study further revealed that OH substitution at the 3' position in pyrogallol moieties contributes to the lower ORAC value of epigallocatechin and epigallocatechin gallate comparing with their non-3'-OH counterparts, such as epicatechin and epicatechin gallate, respectively. Also, numbers of OH substitutions were poorly correlated with the observed ORAC value unlike the DRSC. Overall, results of this study enabled us to hypothesize that substances having a lower TAC value in the ORAC assay compared with that in DPPH assays may pertain to a pro-oxidant effect by generating reactive oxygen species in an aqueous buffer, at a physiological pH. We also propose that substances exhibiting lower TAC value in the ORAC assay compared with that in the DPPH assay are powerful pro-oxidants compared with the substances showing a higher TAC value in the ORAC assay than that in the DPPH assay.

Authors+Show Affiliations

Nutrition Division, R&D Central Research Laboratories, 1-3 Takaramachi, Taiyo Kagaku Co. Ltd, Yokkaichi, Mie 510-0844, Japan. mroy@taiyokagaku.co.jpNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

20109129

Citation

Roy, Molay K., et al. "ORAC and DPPH Assay Comparison to Assess Antioxidant Capacity of Tea Infusions: Relationship Between Total Polyphenol and Individual Catechin Content." International Journal of Food Sciences and Nutrition, vol. 61, no. 2, 2010, pp. 109-24.
Roy MK, Koide M, Rao TP, et al. ORAC and DPPH assay comparison to assess antioxidant capacity of tea infusions: relationship between total polyphenol and individual catechin content. Int J Food Sci Nutr. 2010;61(2):109-24.
Roy, M. K., Koide, M., Rao, T. P., Okubo, T., Ogasawara, Y., & Juneja, L. R. (2010). ORAC and DPPH assay comparison to assess antioxidant capacity of tea infusions: relationship between total polyphenol and individual catechin content. International Journal of Food Sciences and Nutrition, 61(2), 109-24. https://doi.org/10.3109/09637480903292601
Roy MK, et al. ORAC and DPPH Assay Comparison to Assess Antioxidant Capacity of Tea Infusions: Relationship Between Total Polyphenol and Individual Catechin Content. Int J Food Sci Nutr. 2010;61(2):109-24. PubMed PMID: 20109129.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - ORAC and DPPH assay comparison to assess antioxidant capacity of tea infusions: relationship between total polyphenol and individual catechin content. AU - Roy,Molay K, AU - Koide,Motoki, AU - Rao,Theertham P, AU - Okubo,Tsutomu, AU - Ogasawara,Yutaka, AU - Juneja,Lekh R, PY - 2010/1/30/entrez PY - 2010/1/30/pubmed PY - 2010/6/9/medline SP - 109 EP - 24 JF - International journal of food sciences and nutrition JO - Int J Food Sci Nutr VL - 61 IS - 2 N2 - Commercially available tea infusions are the major source of catechins for preparing bottled tea beverages and tea supplements available in the market today. In the present study, we analyzed five tea infusions to measure the total antioxidant capacity (TAC) by oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (DRSC) assays, total polyphenol content by the colorimetric method and individual catechin content by high-performance liquid chromatography. Four major tea catechins were also analyzed for their TAC to reveal differential antioxidant behavior of the tea infusions, resulting in the ORAC and DRSC methods. The correlation coefficients between DRSC and the total polyphenol or total catechin content of the tea infusions were 1.0 and 0.99. However, the values fall to 0.73 and 0.69, respectively, while the ORAC activity was correlated with total polyphenol and total catechin content. Determining the TAC of individual tea catechins showed that ORAC of epicatechin was seven-fold higher than that of epigallocatechin gallate; on the contrary, epigallocatechin gallate showed significantly (P < 0.05) stronger DRSC activity than epicatechin. By evaluating the structure-activity relationship, this study further revealed that OH substitution at the 3' position in pyrogallol moieties contributes to the lower ORAC value of epigallocatechin and epigallocatechin gallate comparing with their non-3'-OH counterparts, such as epicatechin and epicatechin gallate, respectively. Also, numbers of OH substitutions were poorly correlated with the observed ORAC value unlike the DRSC. Overall, results of this study enabled us to hypothesize that substances having a lower TAC value in the ORAC assay compared with that in DPPH assays may pertain to a pro-oxidant effect by generating reactive oxygen species in an aqueous buffer, at a physiological pH. We also propose that substances exhibiting lower TAC value in the ORAC assay compared with that in the DPPH assay are powerful pro-oxidants compared with the substances showing a higher TAC value in the ORAC assay than that in the DPPH assay. SN - 1465-3478 UR - https://www.unboundmedicine.com/medline/citation/20109129/ORAC_and_DPPH_assay_comparison_to_assess_antioxidant_capacity_of_tea_infusions:_relationship_between_total_polyphenol_and_individual_catechin_content_ L2 - http://www.tandfonline.com/doi/full/10.3109/09637480903292601 DB - PRIME DP - Unbound Medicine ER -