cytotoxic activity of selected iranian traditional medicinal plants on colon, colorectal and breast cancer cell lines

background: many natural products from plants have been recognized to exert anticancer activity. in this study, ethanolic extracts of selected medicinal herbs from iranian flora including alyssum homolocarpum fisch. (from seeds), urtica dioica l. (from aerial parts), cichorium intybus l. (from roots) and solanum nigrum l. (from fruits), were evaluated for their cytotoxic effect on different cell lines. methods: cytotoxic effect of these extracts was studied on three different cancer cell lines; colon carcinoma (ht-29), colorectal adenocarcinoma (caco-2) and breast ductal carcinoma (t47d). in addition, swiss mouse embryo fibroblasts (nih 3t3) were used as normal nonmalignant cells. mtt assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was utilized for calculating the cytotoxicity of extracts on cell lines. results: results showed the potent cytotoxic activity of u. dioica ethanolic extract against t47d cell line with ic50 value of 46.14±4.55 µg/ml. other extracts showed poor activity with ic50>100 µg/ml. conclusions: cytotoxic activity recorded in the present study revealed high potential antiproliferative activity of u. dioica ethanolic extract against t47d cell line. the real ic50 values of this extract may be considerably lower than the ic50 measured in our study if its pharmacological active compounds become pure. the results emphasize the importance of studies on u. dioica ethanolic extract to characterize potential components as cytotoxic natural medicines.