Oligonol suppresses lipid accumulation and improves insulin resistance in a palmitate-induced in HepG2 hepatocytes as a cellular steatosis model.

Jae-Yeo Park, Younghwa Kim, Jee Ae Im, Hyangkyu Lee

Index: BMC Complement Altern. Med. 15 , 185, (2015)

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Abstract

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.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.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.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.