Protective Effect of Jujube (Ziziphus jujuba Mill.) Extracts on Ethanol‐induced Liver Injury in Human HepG2 Cells

Abstract

Jujube has a long history of usage as a fruit and remedy. The main biologically active components are reported as vitamin C, phenolic acids, flavonoids, triterpenic acids, and polysaccharides. Oxidative stress plays a crucial role in the progression of alcoholic liver diseases and substances of antioxidant property are of special interest for therapeutic purposes. The purpose of this study was to investigate the protective effect of jujube extracts against ethanol‐induced liver injury in HepG2 cells. HepG2 cells were pretreated with methanol extract of jujube (25–100 μg/mL) and then hepatotoxicity was stimulated by addition of 3% ethanol. With response to ethanol‐challenge, increased amount of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) release were observed, whereas jujube pretreatment significantly reduced the levels of AST and ALT in HepG2 cells without appreciable cytotoxic effects. This protective effect was likely associated with antioxidant potential of jujube extracts, as evidenced by the attenuation of reactive oxygen species (ROS) and malondialdehyde (MDA) production and restoration of the depleted glutathione (GSH) levels in ethanol‐induced HepG2 cells. Considering these properties, quantification of the bioactive compounds is very important. Contents of phenolic acids and flavonoids were confirmed by LC‐MS/MS. Vanillic acid was the highest in jujube extracts followed by benzoic acid, rutin, and coumaric acid. Thus, we concluded that these active compounds may provide a pivotal mechanism for its hepatoprotective action. Further studies are needed to identify the mechanism and active compounds.