In an effort to understand the molecular events contributing to the cytotoxicity activity of resveratrol (RSV),we investigated its effects on human lung adenocarcinoma epithelial cell line A549 at different concentrations.Cellular nucleoside metabolic profiling was determined by an established liquid chromatography-mass spectrometry method in A549 cells.RSV resulted in significant decreases and imbalances of deoxyribonucleoside triphosphates (dNTPs) pools suppressing subsequent DNA synthesis.Meanwhile,RSV at high concentration caused significant cell cycle arrest at S phase,in which cells required the highest dNTPs supply than other phases for DNA replication.The inhibition of DNA synthesis thus blocked subsequent progression through S phase in A549 cells,which may partly contribute to the cytotoxicity effect of RSV.However,hydroxyurea (HU),an inhibitor of RNR activity,caused similar dNTPs perturbation but no S phase arrest,finally no cytotoxicity effect.Therefore,we believed that the dual effect of high concentration RSV,including S phase arrest and DNA synthesis inhibition,was required for its cytotoxicity effect on A549 cells.In summary,our results provided important clues to the molecular basis for the anticancer effect of RSV on epithelial cells.