The AMPK pathway mediates an anti-adipogenic effect of fruits of Hovenia dulcis Thunb.

Hovenia dulcis Thunb. is well known as a treatment for liver disease. Several studies have demonstrated that extracts of Hovenia dulcis Thunb. or its purified compounds can serve as detoxifying agents for alcohol poisoning. However, its anti-obesity effect has not been reported thus far. In this study, the anti-obesity effect of water extracts from the fruits or stems of Hovenia dulcis Thunb. was examined in 3T3-L1 preadipocytes. The cellular lipid contents in 3T3-L1 adipocytes were assessed by Oil Red O staining. Fruits of Hovenia dulcis Thunb. (FHD) significantly inhibit lipid accumulation during adipogenesis in a dosedependent manner, but not stems of Hovenia dulcis Thunb. FHD (100 mu g ml(-1)) significantly down-regulates the expression of the peroxisome proliferator-activated receptor-gamma, CCAAT/enhancer-binding protein-alpha, adipocyte fatty acid-binding protein 2, adiponectin, and resistin, and the inhibition rates were 29.33%, 54.36%, 34.5%, 55.69%, and 60.39%, respectively. In addition, FHD (100 mu g ml-1) also up-regulates the phosphorylation of AMP-activated protein kinase (AMPK)-alpha, liver kinase B1 as a major AMPK kinase, and the downstream substrate acetyl-CoA carboxylase, and the inhibition rates were 43.52%, 38.25%, and 20.39%, respectively. These results indicate that FHD has a significant anti-obesity effect through the modulation of the AMPK pathway, suggesting that FHD has a potential benefit in preventing obesity.