American ginseng and its bioactive compounds inhibit preadipocyte differentiation by suppressing peroxisome proliferator‐activated receptor gamma in 3T3‐L1 cells and human primary preadipocytes (641.11)

American ginseng, a well‐known therapeutic herbal medicine in Asian countries, and the fifth most commonly used natural product in US, has an array of health benefits including preventing cardiovascular disease, diabetes and cancer; however, there are very few reports on obesity prevention. The objectives of the present study are to investigate whether and how American ginseng and its bioactive compounds prevent obesity development in preadipocytes. We found that the whole American ginseng extract (WH, 500‐2000 µg/ml) and its bioactive compounds ginsenoside Rh2 (Rh2, 30, 40, 50, 60 µM), ginsenoside Rg3 (Rg3, 1, 10, 50, 100 µM) and compound K (CoK, 30, 40, 50, 60 µM) dose‐dependently inhibited 3T3‐L1 cell differentiation, which was measured by oil red staining. Similarly, WH, Rh2, Rg3 and CoK also inhibited cell differentiation in human primary preadipocytes (HPP) at much lower concentrations 50‐1000 µg/ml, 5‐20 µM, 1‐50 µM and 5‐20 µM respectively. Further study showed that WH, Rh2, Rg3 and CoK dose‐dependently suppressed both of protein and RNA expressions of peroxisome proliferator‐activated receptor gamma (PPAR‐γ), the key player of preadipocyte differentiation by western blot and real‐time PCR both in 3T3‐L1 and HPP. These results suggest that American ginseng and its selected bioactive compounds may prevent obesity by suppressing preadipocyte differentiation through inhibiting PPAR‐γ expression. Grant Funding Source : Supported by USDA‐CBG grant (TENX‐2011‐02575)