Synthesis and biological evaluation of berberine analogues as novel up-regulators for both low-density-lipoprotein receptor and insulin receptor

Berberine (BBR) is a natural compound with up-regulating activity on both low-density-lipoprotein receptor (LDLR) and insulin receptor (InsR). This one-drug-multiple-target characteristic might be suitable for the treatment of metabolic syndrome. In searching for up-regulators effective for both LDLR and InsR expression, the structure-activity relationship (SAR) analysis for BBR analogues was done. Fourteen BBR analogues were designed, synthesized and biologically evaluated. SAR analysis revealed that appropriate modifications on the phenyl ring A or D of BBR might retain the up-regulatory activities on the expression of both LDLR and InsR. Among these compounds, compound 13a bearing 9-methoxy and 10-hydroxyl on the ring D showed promising activities on either LDLR or InsR gene expression. The 10-hydroxyl of 13a could be an arm to connect proper chemical groups for optimizing drug-bioavailability in vivo. Thus, 13a could be considered to be a parent compound to make pro-drugs for either blood lipids or glucose.