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Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay
OBJECTIVE: Oxygen radical absorbance capacity (ORAC) assay measures the quenching of fluorescent probe by peroxyl radicals. Antioxidants present in biological systems block the quenching of fluorescence probe. We experienced the dynamic quenching of fluorescein, the fluorescence probe used in ORAC a...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6916041/ https://www.ncbi.nlm.nih.gov/pubmed/31843018 http://dx.doi.org/10.1186/s13104-019-4845-4 |
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author | Gunawardena, Harshi Silva, Renuka Ranasinghe, Pathmasiri |
author_facet | Gunawardena, Harshi Silva, Renuka Ranasinghe, Pathmasiri |
author_sort | Gunawardena, Harshi |
collection | PubMed |
description | OBJECTIVE: Oxygen radical absorbance capacity (ORAC) assay measures the quenching of fluorescent probe by peroxyl radicals. Antioxidants present in biological systems block the quenching of fluorescence probe. We experienced the dynamic quenching of fluorescein, the fluorescence probe used in ORAC assay by the human plasma while plasma ORAC assay was optimized. Therefore, for the first time, we report the quenching of fluorescein by human plasma at the initial point of ORAC assay. RESULTS: Aqueous whole and non-protein fractions of plasma were used in the analysis. Since the both fractions showed a similar pattern of quenching at the initial stage, quenched percentage of fluorescein was calculated and added to each sample in subsequent analysis. Addition of extra 20% fluorescein allowed plasma samples to quench the required amount of fluorescein and follow the normal decay curves afterwards. Further, change of fluorescein quenching (ΔF/F(0)) disclosed a dose dependent linear relationship with plasma (R(2) = 0.8). It can be speculated that dynamic quenching exhibited by human plasma biomolecule/s at the initial stage would be of non-protein aqueous phase molecule/s. We suggest initiating further studies to detect, identify and quantify the fluorescein quenching biomolecules present in human plasma for further improvements in plasma ORAC assay. |
format | Online Article Text |
id | pubmed-6916041 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-69160412019-12-30 Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay Gunawardena, Harshi Silva, Renuka Ranasinghe, Pathmasiri BMC Res Notes Research Note OBJECTIVE: Oxygen radical absorbance capacity (ORAC) assay measures the quenching of fluorescent probe by peroxyl radicals. Antioxidants present in biological systems block the quenching of fluorescence probe. We experienced the dynamic quenching of fluorescein, the fluorescence probe used in ORAC assay by the human plasma while plasma ORAC assay was optimized. Therefore, for the first time, we report the quenching of fluorescein by human plasma at the initial point of ORAC assay. RESULTS: Aqueous whole and non-protein fractions of plasma were used in the analysis. Since the both fractions showed a similar pattern of quenching at the initial stage, quenched percentage of fluorescein was calculated and added to each sample in subsequent analysis. Addition of extra 20% fluorescein allowed plasma samples to quench the required amount of fluorescein and follow the normal decay curves afterwards. Further, change of fluorescein quenching (ΔF/F(0)) disclosed a dose dependent linear relationship with plasma (R(2) = 0.8). It can be speculated that dynamic quenching exhibited by human plasma biomolecule/s at the initial stage would be of non-protein aqueous phase molecule/s. We suggest initiating further studies to detect, identify and quantify the fluorescein quenching biomolecules present in human plasma for further improvements in plasma ORAC assay. BioMed Central 2019-12-16 /pmc/articles/PMC6916041/ /pubmed/31843018 http://dx.doi.org/10.1186/s13104-019-4845-4 Text en © The Author(s) 2019 Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. |
spellingShingle | Research Note Gunawardena, Harshi Silva, Renuka Ranasinghe, Pathmasiri Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay |
title | Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay |
title_full | Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay |
title_fullStr | Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay |
title_full_unstemmed | Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay |
title_short | Human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (ORAC) assay |
title_sort | human plasma dynamically quenches the fluorescein at the initial point of oxygen radical absorption capacity (orac) assay |
topic | Research Note |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6916041/ https://www.ncbi.nlm.nih.gov/pubmed/31843018 http://dx.doi.org/10.1186/s13104-019-4845-4 |
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