Genistein Mediates the Anti-Adipogenic Actions of Sophora japonica L. Extracts So-Ra Jung, 1 Young-Jun Kim, 2 A-Ryeong Gwon, 3 Jina Lee, 1 Dong-Gyu Jo, 3 Tae-Joon Jeon, 4 Joung-Woo Hong, 5 Ki-Moon Park, 1 and Kye Won Park 1 1 Department of Food Science and Biotechnology and 3 College of Pharmacy, Sungkyunkwan University, Suwon; 2 Major in Biomodulation, Department of Agricultural Biotechnology, Seoul National University, Seoul; 4 Department of Biological Engineering, Inha University, Incheon; and 5 Graduate School of East-West Medical Science, Kyung Hee University, Yongin, Republic of Korea ABSTRACT Previous studies showed that feeding diets containing the mature fruits of Sophora japonica L. prevented body weight gain and reduced fat mass in high-fat diet-induced obese mice. This observation has led to the hypothesis that extracts from S. japonica L. may inhibit adipocyte differentiation of preadipocytes. To elucidate the possible mechanisms for the anti- obesity action of S. japonica L., its effects on adipocyte differentiation were investigated in C3H10T1=2 mesenchymal stem cells and 3T3-L1 preadipocyte cells. The mature fruit of S. japonica L. was partitioned with ethanol, hexane, dichloromethane, ethyl acetate (EtOAc), and butanol to identify the active fractions. The EtOAc fraction extracts inhibited morphological differentiation and lipid accumulation in the C3H10T1=2 and 3T3-L1 preadipocytes. Molecular studies indicated that the EtOAc fraction extracts also reduced the expression of peroxisome proliferator-activated receptor g and other adipocyte markers. Furthermore, among the fractions, the EtOAc fraction extracts had the highest total phenolic contents, suggesting that the polyphenols in the EtOAc fractions mediated the anti-adipogenic effects. Finally, high-performance liquid chromatography identified genistein, a known anti-adipogenic compound, as the probable mediator of the anti-adipogenic effects of the EtOAc fractions. This work validates the beneficial roles of S. japonica L. in controlling body weight and obesity-related metabolic diseases. KEY WORDS:  adipocyte  C3H10T1=2 cells  differentiation  genistein  obesity  peroxisome proliferator-activated receptor c INTRODUCTION A rapid increase in the prevalence of obesity is a major contributing factor for augmented incidents of metabolic diseases such as cardiovascular disease, cancer, atherosclerosis, and diabetes. This epidemic of obesity is known to be caused by greater caloric intake and less physical activity. 1 Therefore, proper control of obesity has the potential to greatly impact human health and obesity- related symptoms. Numerous anti-obesity strategies are being developed that target appetite suppression, inhibit nutrient absorption, and stimulate energy expenditure. 2,3 However, various medica- tions against obesity have undesirable side effects. 4 There- fore, natural products are attractive alternatives and with fewer side effects than chemically synthesized anti-obesity drugs. 5–7 For example, resveratrol has been suggested as a promising natural anti-obesity compound. Resveratrol can mimic the effects of endurance exercise by activating the SIRT1–PGC1a coactivator complex. 8,9 In addition, peroxi- some proliferator-activated receptor (PPAR) b=d and AMP- activated protein kinase stimulations have been shown to act as exercise mimetics. 10 Other bioactive compounds isolated from natural products such as epigallocatechin-3-gallate, genistein, rutin, and other PPARg antagonists can inhibit adipogenesis and regulate PPARg functions. These PPARg and adipogenic inhibitors thus could provide potential new avenues for the treatment of obesity and its related diseases. Therefore, the identification of natural products against obe- sity and the study of their mechanisms are fueling the development of new applications in the biomedical and food industries. PPARg is the master transcriptional regulator of adipo- genesis. 11 As PPARg is necessary and sufficient for adipo- genesis, its downstream targets are generally considered adipocyte-specific markers. Downstream markers including aP2, CD36, lipoprotein lipase, and adiponectin are known to regulate lipid accumulation, storage, and adipocyte differ- entiation. 12 PPARg can also act as a modulator of glucose homeostasis. The most widely used orally delivered antidi- abetic drug, thiazolidinedione, functions as a PPARg ligand Manuscript received 10 August 2010. Revision accepted 12 December 2010. Address correspondence to: Kye Won Park, Ph.D., Department of Food Science and Biotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea, E-mail: kwpark@skku.edu JOURNAL OF MEDICINAL FOOD J Med Food 14 (4) 2011, 360–368 # Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition DOI: 10.1089=jmf.2010.1324 360