Heme oxygenase-1 mediates the inhibitory effect of ginseng (Panax ginseng) leaf extract on differentiation in 3T3-L1 adipocytes

Background

Obesity, which is defined as the excess accumulation of body fat, poses metabolic diseases that result in significant health risks. Since conventional anti-obesity medications are known to have significant side effects, we tried a pharmacological approach with a natural product. Ginseng (Panax ginseng) is a traditional Asian medicine that possesses antioxidant, anti-inflammatory, and anti-obesogenic properties. However, the mechanism of the anti-obesity effects of ginseng leaf extract (GLE) is not yet understood.

Objective

We investigated the mechanism by which GLE inhibits the differentiation of 3T3-L1 preadipocytes.

Results

GLE treatment was administered throughout the 8 days differentiation period or at three stages of adipocyte differentiation (early: days 0–2; intermediate: days 2–4; or late: after day 4). During adipocyte differentiation, GLE treatment significantly inhibited 3T3-L1 preadipocyte differentiation at the early stage, leading to a notable reduction in lipid accumulation and a decrease in the expression of crucial adipogenic transcription factors that regulate adipocyte differentiation. GLE also increased the expression of HO-1 and Wnt/β-catenin signaling in a dose-dependent manner during adipocyte differentiation. To evaluate the role of HO-1 induced by GLE, we used HO-1 inhibitor SnPP and HO-1 siRNA. Attenuation of HO-1 function and expression inhibited the decrease in lipid accumulation and adipogenic transcription factor expression caused by GLE; furthermore, inhibition of HO-1 suppressed Wnt/β-catenin signaling.

Conclusions

Overall, our results suggest that GLE inhibits the differentiation of 3T3-L1 preadipocytes by regulating HO-1 expression and Wnt/β-catenin signaling. Therefore, GLE could have preventive uses as a natural product for the treatment of obesity.