Quercitin as effective as resveratrol for inflammation with diabetes and obesity

There has been a lot of interesting science, some of it reported here, documenting the benefits of resveratrol for factors contributing to inflammation, insulin resistance, obesity, diabetes and longevity. A paper just published in the American Journal of Clinical Nutrition offers evidence that the valuable phenolic compound quercitin may be even more effective than resveratrol for reducing the inflammation associated with insulin resistance and diabetes. The authors state:

"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...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 [fat cells] treated with tumor necrosis factor-{alpha} (TNF-{alpha})—an inflammatory cytokine elevated in the plasma and adipose tissue of obese, diabetic individuals."

They stimulated fat cells with TNF-{alpha} to promote inflammation after pretreatment with quercetin and trans-RSV, then measured gene and protein markers of inflammation and insulin resistance. What did the data show?

Quercetin, and to a lesser extent trans-RSV, attenuated the TNF-{alpha}–induced expression of inflammatory genes such as interleukin (IL)-6, IL-1β, IL-8, and monocyte chemoattractant protein-1 (MCP-1) and the secretion of IL-6, IL-8, and MCP-1... Quercetin, but not trans-RSV, decreased TNF-{alpha}–induced nuclear factor-{kappa}B transcriptional activity. Quercetin and trans-RSV attenuated the TNF-{alpha}–mediated suppression of peroxisome proliferator–activated receptor {gamma} (PPAR{gamma}) and PPAR{gamma} target genes and of PPAR{gamma} protein concentrations and transcriptional activity...."

Quercitin is known to be helpful for gut inflammation associated with food allergies, and I have found it to be a surprisingly helpful palliative for airborne allergies. In light of this the authors' conclusion is not a surprise:

"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."