Propyl gallate inhibits the growth of HeLa cells via regulating intracellular GSH level

Propyl gallate (PG) as a synthetic antioxidant exerts a variety of effects on tissue and cells. Here, we investigated an involvement of glutathione (GSH) and reactive oxygen species (ROS) in PG-induced inhibition of HeLa cell growth. PG dose-dependently inhibited HeLa cell growth and induced apoptosis at 24 h. The intracellular ROS levels including O₂^{{radical dot} -} were increased or decreased in PG-treated HeLa cells depending on the incubation times (1 or 24 h) and doses (100-1600 μM). PG increased activities of superoxide dismutase (SOD) and catalase in HeLa cells. PG significantly increased GSH depleted cells in a time- and dose-dependent manner. Treatment with 2 mM N-acetyl-cysteine (NAC; a well known antioxidant) slightly prevented 400 μM PG-induced cell death, which was accompanied by an increase in ROS level and a decrease in GSH depletion level. PG induced a G1 phase arrest of the cell cycle. NAC did not affect the cell cycle distributions in PG treated- or untreated-HeLa cells. Conclusively, PG inhibited the growth of HeLa cells via regulating GSH level rather than ROS level. Our present data could provide useful information on the molecular anti-growth mechanisms of PG in cancer cells in relation to ROS and GSH level.