Constituents of Morus alba var. multicaulis leaf improve lipid metabolism by activating the AMPK signaling pathway in HepG2 cells.

Abstract

One new compound, 3Z-1-O-β-D-glucopyranosyl-3-hexene-1,5-diol (1), together with 26 known isolates (2-27) were obtained from the leaf of Morus alba var. multicaulis. Among the known compounds, 7, 11, 12, 14, 15, 18, 19, 23, and 24 were firstly obtained from the Morus genus; 2-5, 8, 10, 13, and 20 were firstly isolated from M. alba. var. multlcaulis. Meanwhile, the NMR data of 20 and 23 have been reported here for the first time. Moreover, compounds 1-11, 13, 21, and 23-27 showed inhibitory effects on triglyceride (TG) accumulation in HepG2 cells. In mechanism, compound 1 could activate the phosphorylation of AMP-activated protein kinase α (AMPKα) to accelerate the β-oxidation of fatty acids via promoting the phosphorylation of acetyl-CoA carboxylase 1 and up-regulating carnitine palmitoyl-transferase 1A. Besides, compound 1 exerted lipolysis effect by activating hormone-sensitive lipase. In brief, compound 1 might play a role by up-regulating phosphorylation of AMPKα, enhancing the fatty acid β-oxidation and lipolysis. 27 compounds were obtained from the leaf of Morus alba var. multicaulis. Among them, 18 showed inhibitory effects on TG accumulation in HepG2 cells. Moreover, the new compound, 3Z-1-O-β-D-glucopyranosyl-3-hexene-1,5-diol (1), was found to play a role by up-regulating phosphorylation of AMPKα, enhancing the fatty acids β-oxidation and lipolysis.