(21-12-10) Quercetin is equally or more effective than resveratrol in attenuating tumor necrosis factor-

Quercetin is equally or more effective than resveratrol in attenuating tumor necrosis factor-??mediated inflammation and insulin resistance in primary human adipocytes1,2,3
1. Chia-Chi Chuang,
2. Kristina Martinez,
3. Guoxiang Xie,
4. Arion Kennedy,
5. Akkarach Bumrungpert,
6. Angel Overman,
7. Wei Jia, and
8. Michael K McIntosh
+ Author Affiliations
1. 1From the Department of Nutrition, University of North Carolina?Greensboro, Greensboro, NC (C-CC, KM, AK, AO, and MKM); the University of North Carolina?Greensboro Center for Research Excellence in Bioactive Food Components, Kannapolis, NC (GX and WJ); and the Department of Nutrition, Faculty of Public Health, Mahidol University, Bangkok, Thailand (AB).
? ↵2 Supported in part by a grant from the WB Kellogg Institute for Food and Marketing and the North Carolina Agricultural Research Service (NCARS 02288).
? ↵3 Address correspondence to MK McIntosh, Department of Nutrition, 318 Stone Building, PO Box 26170, University of North Carolina?Greensboro, Greensboro, NC 27402-6170. E-mail: [email protected].
Abstract
Background: Quercetin and trans-resveratrol (trans-RSV) are plant polyphenols reported to reduce inflammation or insulin resistance associated with obesity. Recently, we showed that grape powder extract, which contains quercetin and trans-RSV, attenuates markers of inflammation in human adipocytes and macrophages and insulin resistance in human adipocytes. However, we do not know how quercetin and trans-RSV individually affected these outcomes.
Objective: The aim of this study was to examine the extent to which quercetin and trans-RSV prevented inflammation or insulin resistance in primary cultures of human adipocytes treated with tumor necrosis factor-? (TNF-?)?an inflammatory cytokine elevated in the plasma and adipose tissue of obese, diabetic individuals.
Design: Cultures of human adipocytes were pretreated with quercetin and trans-RSV followed by treatment with TNF-?. Subsequently, gene and protein markers of inflammation and insulin resistance were measured.
Results: Quercetin, and to a lesser extent trans-RSV, attenuated the TNF-??induced expression of inflammatory genes such as interleukin (IL)-6, IL-1?, IL-8, and monocyte chemoattractant protein-1 (MCP-1) and the secretion of IL-6, IL-8, and MCP-1. Quercetin attenuated TNF-??mediated phosphorylation of extracellular signal?related kinase and c-Jun-NH2 terminal kinase, whereas trans-RSV attenuated only c-Jun-NH2 terminal kinase phosphorylation. Quercetin and trans-RSV attenuated TNF-??mediated phosphorylation of c-Jun and degradation of inhibitory ?B protein. Quercetin, but not trans-RSV, decreased TNF-??induced nuclear factor-?B transcriptional activity. Quercetin and trans-RSV attenuated the TNF-??mediated suppression of peroxisome proliferator?activated receptor ? (PPAR?) and PPAR? target genes and of PPAR? protein concentrations and transcriptional activity. Quercetin prevented the TNF-??mediated serine phosphorylation of insulin receptor substrate-1 and protein tyrosine phosphatase-1B gene expression and the suppression of insulin-stimulated glucose uptake, whereas trans-RSV prevented only the TNF-??mediated serine phosphorylation of insulin receptor substrate-1.
Conclusion: These data suggest that quercetin is equally or more effective than trans-RSV in attenuating TNF-??mediated inflammation and insulin resistance in primary human adipocytes.

1.Source: Am J Clin Nutr December 2010 vol. 92 no. 6 1511-1521

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