[Effects of flavonoids from Gynostemma pentaphyllum on A549 cells damaged by hydrogen peroxide].

ABSTRACT

This study focuses on the therapeutical effect of flavonoids from Gynostemma pentaphyllum on human lung carcinoma A549 cells induced by H2O2 oxidative stress and its possible mechanisms. The oxidative damage model was established using different concentrations H2O2 to induce A549 cell for different hours, and then treated with the flavonoids for 10 hours. The effects of flavonoids from G. pentaphyllum on cell viability of A549 cell damaged by H2O2 were detected by MTT assay. The contents of ROS were detected by DCFH-DA fluorescent probe method via flow cytometer. The contents of MDA, SOD and GSH were detected by TBA，NBT and DTNB-linked colorimetry assay, respectively. Expressions levels of Nrf2, NQO1 and HO-1 in A549 cells were evaluated by Western blot. The results showed that the cell activity was decreasing with the rise of H2O2 concentration within the range of 200-700 µmol·L⁻¹. The cell viability was 60.4% after treated with 500 µmol·L⁻¹H2O2 for 10 h, so it was chosen to be as an oxidant stress model. Compared with normal group，the contents of SOD, GSH and HO-1 expressions were lower after damaged with H2O2. On the contrary, the contents of ROS and MDA expressions were increased. Compared with model group, the contents of SOD, GSH and the expressions of Nrf2, NQO1 and HO-1 were increased after treated with flavonoids from G. pentaphyllum. The above results demonstrate that flavonoids from G. pentaphyllum may attenuate the effect of H2O2-induced oxidative stress on A549 cell by resisting oxidation. The finding may provide a biological evidence for the application of the G. pentaphyllum to fight the oxidative stress related diseases.