Isocoumarins and Benzoquinones with Their Proprotein Convertase Subtilisin/Kexin Type 9 Expression Inhibitory Activities from Dried Roots of .

A phytochemical investigation of the -hexane-soluble chemical constituents roots allowed for selection using a proprotein convertase subtilisin-kexin type 9 (PCSK9) mRNA expression monitoring assay in HepG2 cells. This led to the isolation of two previously undescribed isocoumarins of natural origin, 8'Z,11'Z-octadecadienyl-6,8-dihydroxyisocoumarin () and 3-pentadecyl-6,8-dihydroxyisocoumarin (), along with 20 previously reported compounds (-). All of the structures were established using NMR spectroscopic data and MS analysis. Of the isolates, and were found to inhibit PCSK9, inducible degrader of the low-density lipoprotein receptor (IDOL), and SREBP2 mRNA expression. Further computational dockings of both and to C-ring of IDOL E3 ubiquitin ligase predicted the mechanism behind the inhibitory effect of these compounds on the enzyme.