Yellow loosestrife (Lysimachia vulgaris) and High cholesterol: evidence and sources

A phytochemical investigation of the n -hexane-soluble chemical constituents of Lysimachia vulgaris 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 ( 1 ) and 3-pentadecyl-6,8-dihydroxyisocoumarin ( 2 ), along with 20 previously reported compounds ( 3 - 22 ). All of the structures were established using NMR spectroscopic data and MS analysis. Of the isolates, 1 and 3 were found to inhibit PCSK9, inducible degrader of the low-density lipoprotein receptor (IDOL), and SREBP2 mRNA expression. Further computational dockings of both 1 and 3 to C-ring of IDOL E3 ubiquitin ligase predicted the mechanism behind the inhibitory effect of these compounds on the enzyme.

The liver X receptors (LXRs) are major regulators of lipogenesis, and their reduced activation by an inhibitor could be a treatment strategy for fatty liver disease. Small molecules originating from dietary food are considered suitable and attractive drug candidates for humans in terms of safety. In this study, an edible plant, Lysimachia vulgaris (LV), used as a traditional and medicinal food in East Asia was evaluated for lipogenesis decreasing effects. Activity-guided fractionation was performed, and the isolated compounds were identified using spectroscopic methods. We conducted in vitro real-time polymerase chain reaction (PCR) and Western blotting as well as histological and biochemical analyses following in vivo treatments. Using a high-fat diet animal model, we confirmed that LV extracts (LVE) decreased lipogenic metabolism and restored liver function to control levels. To identify active components, we conducted activity-guided fractionation and then isolated compounds. Two compounds, loliolide and pinoresinol, were identified in the dichloromethane fraction, and they significantly attenuated the expression levels of lipogenic factors including sterol regulatory element-binding protein (SREBP)-1, stearoyl-CoA desaturase 1 (SCD1), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC). Importantly, loliolide and pinoresinol significantly accelerated the protein degradation of LXRs by enhanced ubiquitination, which inhibited lipogenesis. These results suggest that loliolide and pinoresinol might be potential candidate supplementary treatments for nonalcoholic fatty liver disease (NAFLD) by reducing lipogenesis through increased ubiquitination of LXRs.