High hydrostatic pressure extract of Siegesbeckia orientalis inhibits adipogenesis through the activation of the Wnt/β-catenin signaling pathway

St. Paul's Wort (Siegesbeckia orientalis L.) confers anti-oxidative, anti-inflammatory, anti-allergic, anti-infertility, and immunosuppressive properties. Here, we elucidated whether high hydrostatic pressure extract of St. Paul's Wort (SPW-HHPE) had anti-adipogenic activity. SPW-HHPE inhibited adipogenesis by reducing intracellular lipid accumulation. SPW-HHPE reduced the mRNA and protein expression of adipogenic regulatory factors [peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding protein alpha (C/EBPα), and sterol regulatory element binding protein-1c]. In addition, SPW-HHPE decreased the mRNA expression levels of lipogenic enzymes (fatty acid synthase and acetyl-CoA carboxylase) as well as adipocytokines (adiponectin and leptin). The inhibitory effect of SPW-HHPE on adipogenesis was mainly attributed to the enhancement of the Wnt/β-catenin signaling pathway. When β-catenin siRNA was transfected into 3T3-L1 adipocytes, the mRNA expression of PPARγ and C/EBPα was upregulated; however, their expression was attenuated by SPW-HHPE. These results suggest that SPW-HHPE suppresses adipogenesis by stimulating Wnt/β-catenin pathway.