Abstract
Pyranoanthocyanins have been reported to possess better chemical stability and bioactivities than monomeric anthocyanins in some aspects. The hypocholesterolemic activity of pyranoanthocyanins is unclear. In view of this, this study was conducted to compare the cholesterol-lowering activities of Vitisin A with the anthocyanin counterpart Cyanidin-3-O-glucoside(C3G) in HepG2 cells and to investigate the interaction of Vitisin A with the expression of genes and proteins associated with cholesterol metabolism. HepG2 cells were incubated with 40 μM cholesterol and 4 μM 25-hydroxycholeterol with various concentrations of Vitisin A or C3G for 24 h. It was found that Vitisin A decreased the cholesterol levels at the concentrations of 100 μM and 200 μM with a dose-response relationship, while C3G exhibited no significant effect on cellular cholesterol. Furthermore, Vitisin A could down-regulate 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR) to inhibit cholesterol biosynthesis through a sterol regulatory element-binding protein 2 (SREBP2)-dependent mechanism, and up-regulate low-density lipoprotein receptor (LDLR) and blunt the secretion of proprotein convertase subtilisin/kexin type 9 (PCSK9) protein to promote intracellular LDL uptake without LDLR degradation. In conclusion, Vitisin A demonstrated hypocholesterolemic activity, by inhibiting cholesterol biosynthesis and enhancing LDL uptake in HepG2 cells.