Fig. 1

Dosage and time effect of Solamargine on cellular proliferation and viability. a Proliferation of WM115 and WM239 as measured by alamarBlue assay was reduced by 50 % upon treatment with 6 µM (IC₅₀) of Solamargine, while benign WM35 and the normal cells did not show significant reduction in proliferation at doses as high as 10 µM. The graph represents the mean ± S.D (error bars) of four independently repeated experiments. b Viability of WM115 and WM239 was reduced by 50 % after 30 min of Solamargine IC₅₀ administration; however WM35 cell viability was not significantly affected even after 2.5 h of drug administration. c Mitochondrial membrane potential as revealed by JC-1 aggregate signal was significantly reduced in WM239 cells and to a lesser extent in WM115 cells, when compared to control untreated cells. There was no significant reduction in mitochondrial membrane potential in either WM35 benign melanoma cells or normal BAEC cells. d and e The IC₅₀ (6 µM) and IC₇₀ (10 µM) of Solamargine treatment significantly reduced colony formation ability of all the melanoma cell lines in the study; the most profound decrease was noticed in WM239, N = 4, p < 0.0001