O. majorana extract induces a dose-dependent activation of γH2AX, a marker of DNA double-strands breaks, in MDA-MB 231 cells.

(A) Western blot analysis of phosphor-H2AX (ser 139) in MDA-MB231 cells exposed for 6 and 24h with the indicated concentrations of OME or equal volume of vehicle (ethanol) as control. (B) Immunofluorescence staining for γH2AX in OME-treated MDA-MB 231cells. Cells were treated with vehicle or 150, 300 and 450 µg/mL extract for 24 h, fixed, permeabilized, and then processed for immunofluorescence using antibodies against p-H2AX (ser 139) protein. DAPI was used as a nuclear stain.