Quercetin metabolites downregulate cyclooxygenase-2 transcription in human lymphocytes ex vivo but not in vivo

de Pascual-Teresa, Sonia, Johnston, Kelly L., DuPont, M. Susan, O'Leary, Karen A., Needs, Paul W., Morgan, Linda M., Clifford, Mike N., Bao, Yongping ORCID: https://orcid.org/0000-0002-6425-0370 and Williamson, Gary (2004) Quercetin metabolites downregulate cyclooxygenase-2 transcription in human lymphocytes ex vivo but not in vivo. Journal of Nutrition, 134 (3). pp. 552-557. ISSN 1541-6100

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Flavonoids have the potential to modulate inflammation by inhibition of cyclooxygenase-2 (COX-2) transcription. In this study, we compared the effect of the human flavonoid plasma metabolites (quercetin 3'-sulfate, quercetin 3-glucuronide and 3'-methylquercetin 3-glucuronide) on expression of COX-2 mRNA in human lymphocytes ex vivo using TaqMan real-time RT-PCR. We show that the flavonoid quercetin metabolites as detected in human plasma at physiologically significant concentrations inhibit COX-2 expression in human lymphocytes ex vivo. To examine the effect in vivo, we measured COX-2 mRNA levels in 8 subjects (5 men and 3 women) participating in a 3-way, single-blind, randomized crossover study after consumption of a single meal of white, low-quercetin onions, compared with yellow, high-quercetin onions. After consumption of high-quercetin onions, quercetin conjugates were detected in plasma (up to a maximum concentration of 4 micro mol/L at approximately 1 h). However, the expression of COX-2 mRNA in lymphocytes was unchanged by the consumption of high-quercetin onions compared with the low-quercetin group. The results show that a single high dose of the flavonoid quercetin from onions does not change COX-2 mRNA expression in human lymphocytes in vivo even though this change occurred in vitro and ex vivo.

Item Type: Article
Uncontrolled Keywords: base sequence,biotransformation,cyclooxygenase 2,dna primers,gene expression regulation, enzymologic,humans,isoenzymes,kinetics,lymphocytes,membrane proteins,onions,prostaglandin-endoperoxide synthases,quercetin,rna, messenger,reverse transcriptase polymerase chain reaction,time factors,transcription, genetic
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: EPrints Services
Date Deposited: 25 Nov 2010 11:12
Last Modified: 24 Oct 2022 02:37
URI: https://ueaeprints.uea.ac.uk/id/eprint/14504
DOI: 10.1093/jn/134.3.552

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