title: Oligonol suppresses lipid accumulation and improves insulin resistance in a palmitate-induced in HepG2 hepatocytes as a cellular steatosis model.
abstract: BACKGROUND
  Oligonol is a low molecular weight form of polyphenol polymers derived from lychee fruits. Several studies suggest that Oligonol has an anti-obesity effect. Since obesity is tightly associated with insulin resistance, we investigated a possible remission effect of Oligonol on lipid accumulation and insulin resistance in human hepatic HepG2 cells.
  
  
  METHODS
  HepG2 cells were treated with palmitate for 24 h to induce cellular hepatic steatosis and insulin resistance. The cells were then treated with Oligonol at subtoxic concentrations and examined for lipid metabolism, cytokine production, and insulin signaling using quantitative RT-PCR and western blot analysis.
  
  
  RESULTS
  Oligonol treatment reversed the palmitate-induced intracellular lipid accumulation, down regulated the expression of lipogenic genes, and up-regulated genes for fatty acid degradation. Oligonol restored insulin sensitivity, as was determined by the phosphorylation states of IRS-1. Oligonol also inhibited STAT3-SOCS3 signaling and increased AMPK phosphorylation in HepG2 cells.
  
  
  CONCLUSIONS
  Oligonol treatment improved palmitate-induced cellular steatosis and insulin resistance in HepG2 cells with concomitant reduction of inflammatory cytokines and decrease in STAT3-SOCS3 and AMPK-mTOR pathways. Oligonol may have beneficial effects in lipid metabolism and insulin resistance in the liver.
authors.affiliation: Department of Clinical Nursing Science, Yonsei University College of Nursing, 120-752, Seoul, Korea. legolas018@naver.com.|Nursing Policy and Research Institute, Biobehavioral Research Center, Yonsei University, 120-752, Seoul, Korea. legolas018@naver.com.
authors.forename: Jae-Yeo
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Emergency Medical Technology, Kyuongil University, 712-701, Gyeongsan, Kyungbook, Korea. yhkim15@daum.net.
authors.forename: Younghwa
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Sport and Medicine Research Center, INTOTO Inc., 401 Dawoo BD, 90-6 Daeshin-Dong, 120-160, Seodaemun-Gu, Seoul, Korea. jeaeim@hanmail.net.
authors.forename: Jee Ae
authors.initials: JA
authors.lastname: Im
authors.affiliation: Department of Clinical Nursing Science, Yonsei University College of Nursing, 120-752, Seoul, Korea. hkyulee@yuhs.ac.|Nursing Policy and Research Institute, Biobehavioral Research Center, Yonsei University, 120-752, Seoul, Korea. hkyulee@yuhs.ac.
authors.forename: Hyangkyu
authors.initials: H
authors.lastname: Lee
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D005234:Fatty Liver / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D007333:Insulin Resistance; D050356:Lipid Metabolism / Q000187:drug effects*; D008954:Models, Biological; D010636:Phenols / Q000494:pharmacology*
chemical_list: D010636:Phenols; C514283:oligonol; D002392:Catechin