Quercetin-rich onion peel extract suppresses adipogenesis by down-regulating adipogenic transcription factors and gene expression in 3T3-L1 adipocytes

BACKGROUNDOnion peel contains a high amount of quercetin, which has been reported to have anti-cholesterol, antithrombotic and insulin-sensitizing properties. This study aimed to elucidate the anti-adipogenic effects of quercetin-rich onion peel extract (OPE) and to compare it with commercially available quercetin using 3T3-L1 preadipocytes. RESULTSWithout affecting cell viability, both OPE and quercetin averted adipogenesis, as characterized by dose-dependent decreases in intracellular triglyceride content and glycerol 3-phosphate dehydrogenase activity, but the effect was more pronounced with OPE than with quercetin. The mRNA expression levels of key adipogenic genes such as PPAR, C/EBP, FABP4, aP2 and LPL were decreased in a dose-dependent manner by both OPE and quercetin. CONCLUSIONThe results indicate that OPE treatment significantly prevents intracellular lipid accumulation via hyperactivation of genes regulating lipolysis as compared with quercetin alone. (c) 2014 Society of Chemical Industry