Prenylated Flavonoids from the Roots and Rhizomes of <i>Sophora tonkinensis</i> and Their Effects on the Expression of Inflammatory Mediators and Proprotein Convertase Subtilisin/Kexin Type 9

Abstract

Seven new prenylated flavonoids (1–7) and one new prenylated phenylpropiophenone (8) were isolated from roots and rhizomes of Sophora tonkinensis, along with nine known compounds (9–17). The structures 1–8 were elucidated by spectroscopic data analysis and comparison with reported values. Compounds 8 and 12 (7-methoxyebenosin) showed inhibitory activities against nitric oxide production in lipopolysaccharide-induced RAW264.7 cells, with IC50 values of 8.1 and 6.2 μM, respectively. They also significantly lowered expression of CSF2, TNF, and IL-1β. Lonchocarpol A (10) and erybraedin D (16) at concentrations of 20 μM downregulated proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA expression in HepG2 cells. Moreover, erybraedin D (16) inhibited PCSK9 protein synthesis (IC50 7.8 μM), while simultaneously activating AMP-activated protein kinase and acetyl-CoA carboxylase.