Lynn Cialdella-Kam, Sujoy Ghosh, Mary Pat Meaney, Amy M. Knab, R. Andrew Shanely and David C. Nieman (2017). Quercetin and Green Tea Extract Supplementation Downregulates Genes Related to Tissue Inflammatory Responses to a 12-Week High Fat-Diet in Mice. Nutrients 9(7) 773.
1 Department of Nutrition, School of Medicine—WG 48, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
2 Program in Cardiovascular & Metabolic Diseases and Center for Computational Biology, Duke NUS Medical School, 8 College Road, Singapore 169857, Singapore
3 Department of Exercise Physiology, School of Health Sciences, Winston-Salem State University, 601 S. Martin Luther King Jr. Drive, Winston-Salem, NC 27110, USA
4 Levine Center for Health and Wellness, Queens University of Charlotte, 1900 Selwyn Avenue, Charlotte, NC 28274, USA
5 Department of Health & Exercise Science, Appalachian State University, ASU Box 32071, 111 Rivers Street, 050 Convocation Center, Boone, NC 28608, USA
6 Human Performance Laboratory, North Carolina Research Campus, Appalachian State University, 600 Laureate Way, Kannapolis, NC 28081, USA
Quercetin (Q) and green tea extract (E) are reported to counter insulin resistance and inflammation and favorably alter fat metabolism. We investigated whether a mixture of E + Q (EQ) could synergistically influence metabolic and inflammation endpoints in a high-fat diet (HFD) fed to mice. Male C57BL/6 mice (n = 40) were put on HFD (fat = 60%kcal) for 12 weeks and randomly assigned to Q (25 mg/kg of body weight (BW)/day), E (3 mg of epigallocatechin gallate/kg BW/day), EQ, or control groups for four weeks. At 16 weeks, insulin sensitivity was measured via the glucose tolerance test (GTT), followed by area-under-the-curve (AUC) estimations. Plasma cytokines and quercetin were also measured, along with whole genome transcriptome analysis and real-time polymerase chain reaction (qPCR) on adipose, liver, and skeletal muscle tissues. Univariate analyses were conducted via analysis of variance (ANOVA), and whole-genome expression profiles were examined via gene set enrichment. At 16 weeks, plasma quercetin levels were higher in Q and EQ groups vs. the control and E groups (p < 0.05). Plasma cytokines were similar among groups (p > 0.05). AUC estimations for GTT was 14% lower for Q vs. E (p = 0.0311), but non-significant from control (p = 0.0809). Genes for cholesterol metabolism and immune and inflammatory response were downregulated in Q and EQ groups vs. control in adipose tissue and soleus muscle tissue. These data support an anti-inflammatory role for Q and EQ, a result best captured when measured with tissue gene downregulation in comparison to changes in plasma cytokine levels.