Sodium arsenite and arsenic trioxide differently affect the oxidative stress, genotoxicity and apoptosis in A549 cells: an implication for the paradoxical mechanism.

•Trivalent inorganic arsenic induced paradoxical effects.•Paradoxical effects result from cytotoxicity, genotoxicity, oxidative stress and apoptosis.•Sodium arsenite and arsenic trioxide differential affect multiple biological outcomes.•Arsenic trioxide is shown to be a more powerful toxic than sodium arsenite.