Radiosensitizing effect of plumbagin on mouse melanoma cells grown in vitro.

Mouse melanoma cells were treated with plumbagin, a naphthoquinone, from the plant Plumbago rosea at 0.5 microgram/ml (PI) for 60 min either alone or followed by 2 Gy gamma radiation (RT). Response to the different treatments was assessed by following the cell growth up to 5 days post treatment. PI alone produced a significant decrease in the cell count on days 3 and 4, whereas RT treatment significantly enhanced the growth inhibitory effect when compared to RT or PI alone. These findings suggests the radiosensitizing effect of PI on mouse melanoma cells in vitro, supporting the earlier in vivo findings.