Pyrogallol inhibits the growth of human pulmonary adenocarcinoma A549 cells by arresting cell cycle and triggering apoptosis

Pyrogallol (PG) is a polyphenol compound and has been known to be an O ₂^•- generator. We evaluated the effects of PG on the growth of human pulmonary A549 cells in relation to the cell cycle and apoptosis. Treatment with 50 or 100 μM PG significantly inhibited the cell growth of A549 for 72 h. DNA flow cytometric analysis indicated that PG slightly induced a G1 phase arrest of the cell cycle at 24 or 48 h, but did not induce the specific cell cycle arrest at 72 h. Intracellular GSH depletion was observed in PG-treated cells. PG induced apoptosis in A549 cells, as evidenced by sub-G1 cells, annexin V staining cells, and the loss of mitochondrial membrane potential (ΔΨ_m). The intracellular ROS (reactive oxygen species) level including O,₂^- increased in PG-treated A549 cells at 24 and 48 h, and persisted at 72 h. The changes in GSH as well as ROS levels by PG affected the cell viability in A549 cells. In conclusion, PG inhibited the growth of human pulmonary A549 cells by inducing cell cycle arrest as well as triggering apoptosis.