Bioactive flavonoids and stilbenes from the leaf of Morus alba var. multicaulis

Twenty-two flavonoids and stilbenes (1-22) were obtained from the leaf of Morus alba var. multicaulis. Among them, morusalbanosides A (1), B₁ (2), and B₂ (3) were new compounds. Moreover, compounds 1, 3, 4-11, 15-18, and 22 displayed inhibitory effects on triglyceride (TG) accumulation in HepG2 cells in a concentration dependent manner. Furthermore, compounds 1, 3, 11, and 22 could activate the phosphorylation of AMP-activated protein kinase α (AMPKα), reduce the synthesis of TG by inhibiting the expression of fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1). While, only compounds 1 and 11 could promote the phosphorylation of acetyl-CoA carboxylase 1 (ACC1) and accelerate the oxidation of fatty acids by up-regulating carnitine palmitoyltransferase 1A (CPT1A). In brief, this study found that most of the researched flavonoids and stilbenes could regulate TG metabolism in vitro. They might play the role by up-regulating phosphorylation of AMPKα, inhibiting TG biosynthesis, and promoting the oxidation of fatty acids.