The inhibitory effect of saponin derived from Cheonggukjang on adipocyte differentiation In vitro

Saponin compounds in cheonggukjang, a traditional Korean fermented soy food, were quantitatively evaluated, and their antiobesity effect was studied. Two saponin groups, i.e., soyasapogenol A and B, were isolated from cheonggukjang. The soyasapogenol B content was more than four times that of soyasapogenol A, and the proportion of both saponin groups was unaltered during the fermentation process despite a slight decrease in the saponin content due to steam treatment and fermentation. The saponin content of cheonggukjang fermented for 45 h was comparable to that of commercial soy products. The saponin extract significantly inhibited adipocyte differentiation in 3T3-L1 preadipocyte cells. Accumulation of triglycerides was inhibited by 25%, and activation of AMP-activated protein kinase (AMPK), a key regulator of energy balance and fat metabolism, was affected by the saponin extract. AMPK activation was stimulated more by soyasapogenol B than by soyasapogenol A. Therefore, that cheonggukjang saponin may be a potential antiobesity agent.