Pentamethylquercetin Improves Adiponectin Expression in Differentiated 3T3-L1 Cells via a Mechanism that Implicates PPARγ together with TNF-α and IL-6

Adiponectin is an adipocyte-derived hormone that plays a pivotal role in the regulation of lipid and glucose metabolism. Up-regulation of adiponectin expression and production has been shown to benefit for metabolic disorders, including type 2 diabetes, hyperlipidemia, etc. The present study investigated whether the novel polymethoxylated flavonoid pentamethylquercetin (PMQ), a member of polymethoxylated flavonoids family which is present in seabuckthorn (Hippophae L.) would affect adiponectin production in differentiated 3T3-L1 adipocytes. It was found that PMQ increased the adiponectin mRNA and protein expressions in adipocytes in time-and concentration-dependent manners. The PPAR gamma pathway plays a important roles in this effect of PMQ because blockade of PPAR gamma by GW9662 eliminates the PMQ-induced up-regulation of adiponectin expression. Furthermore, significant decreases of mRNA expression and secretion of TNF-alpha and IL-6 were also observed in PMQ-treated cells. Taken together, our study demonstrated that PMQ up-regulates adiponectin expression via a mechanism that implicates PPAR gamma together with TNF-alpha and IL-6, suggesting that PMQ might be a potential candidate for the treatment of metabolic diseases.