Antioxidative Effect of Rhus javanica Linne Extract Against Hydrogen Peroxide or Menadione Induced Oxidative Stress and DNA Damage in HepG2 Cells

摘要

The free radical scavenging activities and the protective effects of Rhus javanica extracts against oxidative damage induced by reactive oxygen species (ROS) were investigated. n-Hexane, ethyl acetate and water fractions were prepared from a methanolextract DPPH radical, superoxide anion and hydroxyl radical scavenging activities were estimated. Intracellular ROS formation was quantified using fluorescent probes, 2', 7'-dichlorofluorescin diacetate (DCFH-DA) for hydroxyl radical and dinydroethidium(DHE) for super oxide anion. The oxidative DNA damage was investigated by the comet assay in HepG_2 cells exposed either to H_2O_2 or to menadione. The highest IC_(50) values for DPPH radical scavenging activity was found in the ethyl acetate fraction with a value of 5.38 μg/mL. Cells pretreated with >=1 μg/mL of the ethyl acetate extract had significantly increased cell viability compared to control cells, which were not pretreated with the extract Intracellular ROS formation and DNA damage in HepG_2cells, which were pretreated with the various concentrations of Rhus javanica ethyl acetate extract and then incubated either with H_2O_2 or with menadione, reduced in a dose-dependent manner. These findings suggest that Rhus javanica might have biologically active components which have strong protective effects against ROS induced oxidative damages to the biomolecules, such as cell membranes and DNA.