Abstract
Berberine is an isoquinoline alkaloid extracted from Rhizoma coptidis and shows anti-hyperlipidemia effect in vivo and in vitro. We previously found that berberine could decrease the intracellular triglyceride content in human hepatoma HepG2 cells through activation of AMP-activated protein kinase (AMPK), a major regulator of lipid metabolism. Herein, to find a more effective agent, several berberine analogues (A1-A13) were isolated and synthesized, and the triglyceride-lowering effects and potential mechanisms were investigated in HepG2 cells. Among these berberine analogues, 9-O-benzoyl-substituted berberine (A13) showed strong affinity to AMPK and significantly up-regulated the levels of phospho-Thr172 AMPK α subunit. Meanwhile, A13 reduced the cellular triglyceride levels. Furthermore, A13 could mediate the mRNA levels of downstream proteins involved in triglyceride synthesis and fatty acid oxidation of AMPK signaling pathway. These results suggested that A13 exerts a triglyceride-lowering effect via stimulation of AMPK pathway, which may be beneficial to regulate hyperlipidemia.