Camellia euphlebia flower extract inhibits oleic acid-induced lipid accumulation via reduction of lipogenesis in HepG2 cells

Abstract

IntroductionCamellia euphlebia is a medicinal and edible plant used to treat hepatic disease in Southern China. However, there have been no reports on the anti-obesity and hypolipidemic effects of Camellia euphlebia flower. This study evaluated the hepatic lipid-lowering potential of different preparations of Camellia euphlebia flower extracts using in vitro models. MethodsA model of hepatic steatosis in the HepG2 cells was induced by oleic acid. HepG2 cells were divided into control group, oleic acid group, oleic acid plus aqueous extract group and oleic acid plus ethanol extract group. The cytotoxicity was quantitatively assessed by methyl-thiazolyl-tetrazolium and lactate dehydrogenase release assay. Lipid accumulation and intracellular triglyceride level were also evaluated by oil red O staining and a commercially available assay kit respectively. Expressions of 3-hydroxy-3-methylglutaryl CoA reductase, fatty acid synthase, acetyl-CoA carboxylase and glycerol-3-phosphate acyl transferase genes in the HepG2 cells were examined by reverse transcription polymerase chain reaction. ResultsTreatment of HepG2 cells with 100 μg/mL aqueous or ethanol extract significantly reduced lipid accumulation and the level of triglyceride in the cells. Furthermore, pre-treatment of HepG2 cells with 100 μg/mL aqueous extract effectively down-regulated the mRNA levels of fatty acid synthase, 3-hydroxy-3-methylglutaryl CoA reductase and glycerol-3-phosphate acyl transferase, whereas 150 μg/mL ethanol extract only down-regulated the mRNA level of 3-hydroxy-3-methylglutaryl CoA reductase. ConclusionThese results provided support for the potential preventive effect of Camellia euphlebia flower on nonalcoholic fatty liver disease and could partly explain the basis of using Camellia euphlebia for the treatment of fatty liver.