Partially purified Peucedanum japonicum Thunb extracts exert anti-obesity effects in vitro.

Objective: Crude ethanolic extract of Peucedanum japonicum Thunb (PJT) has been identified as an antiobesity and antidiabetic candidate. The aim of this study was to assess the mechanisms related to the antiobesity activity of partially purified PJT ethanol extract in vitro.
Methods: PJT ethanol extract (EE) was partitioned into hexane phase (HP) and residual water phase. The effect of PJT extracts on triacylglycerol (TG) content, lipid metabolism-related gene expression, and energy expenditure was assessed in vitro in 3T3-L1, HepG2, and C2C12 cells. Furthermore, the active components in PJT extracts were partially profiled by high-performance liquid chromatography (HPLC) analysis.
Results: The HP significantly down-regulated lipogenic gene expressions in hepatocytes, inhibited TG accumulation, and decreased the size of 3T3-L1 adipocytes. Moreover, the inhibition of lipid accumulation was at maximum during the adipocyte maturation stage. Furthermore, we found an increase in fat hydrolysis by HP in 3T3-L1. In C2C12 myotubes, the HP tended to enhance energy expenditure. HPLC analysis demonstrated that hydrophobic compounds available in the HP were responsible for antiobesity, which corresponded to the latter peaks on the HPLC chromatogram of EE.
Conclusion: Our study demonstrated that the HP plays a crucial role in regulating lipid metabolism-related gene expressions and energy expenditure in vitro. The results thus provide insight on the activity of HP involved in suppressing obesity and its chemical entities.
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