Figure 9. The effect of methotrexate (MTX) and 6-mercaptopurine (6-MP) when used in combination with quercetin (QUE), apigenin (AP), emodin (EMO), rhein, (RH) or cis-stilbene (CIS) on γ-H2AX foci formation (DNA damage marker): in two lymphoid (Jurkat and CCRF-CEM) and two myeloid (THP-1 and KG-1a) leukemia cell lines.

This was evaluated by the immunofluorescent staining using Alexa Fluor® 647 Mouse anti-H2AX (pS139). Cells were treated with MTX or 6-MP and polyphenols alone and in combination for 24 hrs using their lowest-significant doses (LSD). The data was expressed as medians and ranges (n=4). Data was normalised to the vehicle control which was assigned 0% of γ-H2AX foci formation (DNA damage marker). Effects of combination treatments were statistically classified as synergistic (^*) causing an increase in the percentage of cells with γ-H2AX foci or antagonistic (^#) causing an decrease in the percentage of cells with γ-H2AX foci; when compared to vehicle control, drugs alone and expected values of combination treatments. Statistical significant was set at P≤0.05.