Three new flavonoids from the leaves of oriental tobacco and their cytotoxicity

► Three new flavonoids were isolated from the leaves of oriental tobacco. ► The structures were determined by spectroscopic studies and chemical evidences. ► Compound 1 showed high cytotoxicity against PC3 cell with IC50 values of 2.6 μM. ► Compound 3 showed high cytotoxicity against A549 cell with IC50 values of 1.6 μM.