Representative neutral and alkaline comet profiles of A549, U87MG and MRC5 cells treated with tocotrienols . Based on the comet profiles, mean DNA damage were scored for A549, U87MG and MRC5 cells in response to alpha-, gamma- and delta-tocotrienols treatments for 72 h. Untreated cells show intact nuclei without comet-like appearance. Cells treated with IC50 values of alpha-, gamma- and delta-tocotrienols showing U87MG cells have higher scores of DSBs than A549 cells and MRC5 DNA damage is negligible. No SSBs are found in all treated cells. α-T3: alpha-tocotrienol; γ-T3: gamma-tocotrienol; δ-T3: delta-tocotrienol.