Quercetin is equally or more effective than resveratrol in attenuating tumor necrosis factor-α-mediated inflammation and insulin resistance in primary human adipocytes

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 alpha (TNF alpha) 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 alpha Subsequently gene and protein markers of inflammation and insulin resistance were measured Results Quercetin and to a lesser extent trans RSV attenuated the TNF a induced expression of inflammatory genes such as interleukin (IL) 6 IL I beta IL 8 and monocyte chemoattractant protein 1 (MCP I) and the secretion of IL 6 IL 8 and MCP 1 Quercetin attenuated TNF alpha-mediated phosphorylation of cxtracellular signal related kinase and c Jun NH2 terminal kinase whereas trans RSV attenuated only c Jun NH2 terminal kinase phosphorylation Querce tin and trans RSV attenuated TNF alpha-mediated phosphorylation of c Jun and degradation of inhibitory KB protein Quercenn but not trans RSV decreased TNF a induced nuclear factor kappa B transcnp tional activity Quercetin and trans RSV attenuated the TNF alpha-mediated suppression of peroxisome proliferator activated receptor y (PPAR gamma) and PPAR gamma target genes and of PPAR gamma protein concen trations and transcriptional activity Quercetin prevented the TNF alpha-mediated senne phosphorylation of insulin receptor substrate 1 and protein tyrosine phosphatase kappa B gene expression and the suppression of insulin stimulated glucose uptake whereas trans RSV prevented only the TNF alpha-mediated senne phosphorylation of insulin receptor substrate I Conclusion These data suggest that quercetin is equally or more effective than trans RSV in attenuating TNF alpha-mediated inflamma tion and insulin resistance in primary human adipocytes Am J Chn Ntttr 2010 92 1511-21