Tubeimoside-1 (TBMS1) has been shown to possess promising anticancer potential against various cancer cells. However, its effect against melanoma cells remained enigmatic. In this study, for the first time, we investigated the effect of TBMS1 on cell proliferation, cell cycle, and apoptosis in melanoma A375 cells. In order to examine the effects of TBMS1 on cell proliferation, cell cycle, apoptosis, we performed MTT assays and flow cytometry analysis. The results revealed that TBMS1 decreased the cell viability of melanoma A375 cells. Flow cytometric analysis demonstrated that TBMS1 markedly induced apoptosis of A375 cells and arrested cell cycle at G2/M phase in a dose-dependent manner. Induction of apoptosis involved a decrease in mitochondrial membrane potential, down-regulation of Bcl-2 and up-regulation of Bax before culminating in apoptosis in TBMS1-treated A375 cells. These in vitro results suggested that TBMS1 should be further examined for in vivo activity and molecular mechanism in human melanoma.DOI: http://dx.doi.org/10.3329/bjp.v7i3.11507Bangladesh J Pharmacol 2012; 7: 150-156