Acer okamotoanum Nakai Leaf Extract Inhibits Adipogenesis Via Suppressing Expression of PPAR �� and C/EBP �� in 3T3-L1 Cells

The genus Acer contains several species with various bioactivities including antioxidant, antitumor and anti-inflammatory properties. However, Acer okamotoanum Nakai, one species within this genus has not been fully studied yet. Therefore, in this study, we investigated the anti-adipogenic activities of leaf extract from A. okamotoanum Nakai (LEAO) on 3T3-L1 preadipocytes. Adipogenesis is one of the cell differentiation processes, which converts preadipocytes into mature adipocytes. Nowadays, inhibition of adipogenesis is considered as an effective strategy in the field of anti-obesity research. In this study, we observed that LEAO decreased the accumulation of lipid droplets during adipogenesis and down-regulated the expression of key adipogenic transcription factors such as peroxisome proliferator-activated receptor γ (PPAR γ) and CCAAT/enhancer binding protein α (C/EBP α). In addition, LEAO inactivated PI3K/Akt signaling and its downstream factors that promote adipogenesis by inducing the expression of PPAR γ. LEAO also activated β-catenin signaling, which prevents the adipogenic program by suppressing the expression of PPAR γ. Therefore, we found that treatment with LEAO is effective for attenuating adipogenesis in 3T3-L1 cells. Consequently, these findings suggest that LEAO has the potential to be used as a therapeutic agent for preventing obesity.