Orange peel extract HPMF inhibits fat accumulation by blocking PPARgamma and boosting AMPK and SIRT1

  • Comments: The citrus peel extract polymethoxyflavones (PMFs) already have limited use in cholesterol and triglyceride reduction. This new study is the second in three years that shows the potential of hydroxylated polymethoxyflavones (HPMFs) from orange peel to inhibit adipogenesis, i.e. the growth of fat cells. Small quantities of citrus peel can be eaten (lime, lemon, orange, kumquat etc) and may potentially provide benefits against obesity. However, the consumption of larger quantities is not recommended as it can cause diarrhoea and other side effects. A safer and more standardised way to take polymethoxyflavones is "modified citrus pectin", rich in PMFs, which has been in circulation as a supplement for several years..
  • Source: Suppression of Adipogenesis by 5-hydroxy-3,6,7,8,3',4'-Hexamethoxyflavone from Orange Peel in 3T3-L1 Cells.
  • Abstract: We reported previously that hydroxylated polymethoxyflavones (HPMFs) effectively suppressed obesity in high-fat-induced mouse. In this study, we further investigated the molecular mechanism of action of 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone (5-OH-HxMF), one of major HPMFs in orange peel. Treatment of 5-OH-HxMF effectively inhibited lipid accumulation by 55-60% in a dose-dependent manner. The 5-OH-HxMF attenuated adipogenesis through downregulating adipogenesis-related transcription factors such as peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding proteins (C/EBPs), as well as downstream target fatty acid synthase and acetyl-CoA carboxylase (ACC). 5-OH-HxMF activated adenosine monophosphate-activated protein kinase signaling and silent mating type information regulation 1 (SIRTUIN 1 or SIRT1) in 3T3-L1 adipocytes to decrease lipid accumulation. In addition, the inhibition rate of lipid accumulation was compared between 5-OH-HxMF and 3,5,6,7,8,3',4'-heptamethoxyflavone (HpMF). 5-OH-HxMF inhibited lipid accumulation 15-20% more than HpMF did, indicating that hydroxyl group at position 5 can be a key factor in the suppression of adipogenesis.