Propyl gallate inhibits the growth of HeLa cells via caspase-dependent apoptosis as well as a G1 phase arrest of the cell cycle.

Propyl gallate (PG) as a synthetic antioxidant exerts a variety of effects on tissue and cell functions. Here, we evaluated the effects of PG on the growth of HeLa cells in relation to apoptosis and the cell cycle. PG dose-dependently inhibited the growth of HeLa cells with an IC50 of approximately 800 microM at 24 h. DNA flow cytometric analysis indicated that PG significantly induced a G1 phase arrest of the cell cycle along with an increase in the cyclin-dependent kinase inhibitor (CDKI) p27. In addition, PG induced apoptosis, which was accompanied by the loss of mitochondrial membrane potential (MMP; DeltaPsim), activation of caspase-3 and caspase-8 and PARP cleavage. All the tested caspase inhibitors (pan-caspase, caspase-3, -8 or -9 inhibitor) significantly rescued HeLa cells from PG-induced cell death. However, none of the caspase inhibitors prevented the loss of MMP (DeltaPsim) induced by PG. In conclusion, PG inhibited the growth of HeLa cells via caspase-dependent apoptosis as well as a G1 phase arrest of the cell cycle.