The effect of tamoxifen on the growth of Leishmania major promastigotes and amastigotes in vitro

Treatment of cutaneous leishmaniasis with pentavalent antimony compounds, as an established drug, may have limitations, side effects and recurrence risk. For this reason, finding new and effective drugs is of great importance. In the present study, the effect of tamoxifen on the growth of Leishmania major promastigotes and amastigotes was evaluated in vitro. In this experimental study, the effect of different concentrations (1, 5, 10, 20 and 50 μg/ml) of tamoxifen on Leishmania promastigotes and amastigotes were evaluated in three different times (24, 48 and 72h) and the inhibitory concentration 50 (IC50) was calculated by counting of the parasites. The MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5 biphenyltetrazolium bromide) assay was used to determine the percentage of live promastigotes and amastigotes after adding tamoxifen. The number of promastigotes and amastigotes were declined in the presence of various concentrations of tamoxifen after 24, 48 and 72 hours of culturing. Twenty-four hours after culturing, the number of parasites was 1.07×106 per ml in the control group and the parasite numbers in the concentrations of 1 and 50 μg/ml tamoxifen were 0.95×106 and 0.06×106, respectively. The IC50 value of tamoxifen was 2.64μg/ml. Tamoxifen has antileishmanial effects in vitro; thus, more researches on the effect of tamoxifen in animal models are suggested.