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 μg/ml (Pl) 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. Pl alone produced a significant decrease in the cell count on days 3 and 4, whereas RT treatment significantly decreased the cell count 24 hr after the exposure, which persisted till day 4. Pl treatment before RT significantly enhanced the growth inhibitory effect when compared to RT or Pl alone. These findings suggests the radiosensitizing effect of Pl on mouse melanoma cells in vitro, supporting the earlier in vivo findings.