Dietary Flavonoids Suppress Adipogenesis in 3T3-L1 Preadipocytes
PO-JUNG CHIEN1, YING-CHEN CHEN2, SHOU-CHIN LU3 AND FUU SHEU2*
1. Department of Food Science, Yuanpei University of Science and Technology, Hsinchu City 30051, Taiwan, R.O.C.
2. Department of Horticulture, College of Agriculture and Bioresources, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei City 10673, Taiwan, R.O.C.
3. Graduated Institute of Biochemistry and Molecularbiology, College of Medicine, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei City 10673, Taiwan, R.O.C.
(Received: November 24, 2004; Accepted: March 1, 2005)
ABSTRACT
This study examined how dietary flavonoids, including catechin, quercetin and kaempferol, affect the differentiation of 3T3-L1 adipocytes. Eight days following induction for differentiation with MDI-medium and simultaneously with the tested flavonoids (day 8), our study found significantly reduced (p < 0.05) intracellular triacylglycerol accumulations of 3T3-L1 cells. This compared positively against the smaller reduction in accumulation found in the vehicle control. This suppressing effect was found to be dose-dependent, and a 54.4%, 45.7% and 29.9% decrease of triacylglycerol production was observed for catechin, quercetin and kaempferol (25-100 μM), respectively. Additionally, RT-PCR assays demonstrated that catechin, quercetin and kaempferol markedly reduced the mRNA expressions of C/EBP-α, PPAR-γ and SREBP-1, which are key transcription-factors for 3T3-L1 adipogenesis. These results suggest that dietary flavonoids suppress 3T3-L1 differentiation by down-regulating adipogenic transcription-factors. Further study recommended to explore the potential health benefits of catechin, quercetin and kaempferol in the control of body weight.
Key words: dietary flavonoids, 3T3-L1 adipocyte, adipogenic differentiation