Mulberry leaf polyphenol extract improves obesity by inducing adipocyte apoptosis and inhibiting preadipocyte differentiation and hepatic lipogenesis

This study investigated the effects of mulberry leaf extract (MLE) and mulberry leaf polyphenol extract (MLPE) on lipid accumulation in 3T3-L1 cells and obesity in mice fed a high-fat diet (HFD). MLPE was extracted from mulberry leaves using ethanol, and those polyphenolic compounds that can be analysed by HPLC. Both MLE and MLPE efficiently suppressed the expression of SREBP-1c and PPAR-γ proteins and the target genes A-FABP and FAS, whereas both of these compounds increased phosphorylation of AMPK in vivo and in vitro. Treatment of quercetin, caffeic acid, hydroxyflavin and hesperetin, the main ingredients of MLPE, also inhibited the differentiation of 3T3-L1 preadipocytes. In addition, orally administering MLE significantly reduced body weight gain and lipid accumulation in the liver and serum/hepatic triglyceride and total cholesterol levels compared with those in the HFD group. Therefore, the mulberry leaf may be used as a dietary supplement in patients with certain diseases with obesity involvement.