growth inhibitory impact of peganum harmala l. on two breast cancer cell lines

background: ß-carbolines, harmaline and harmine, are the major alkaloids presenting in the seeds of the peganum harmala l. these alkaloids are known as herbal active principals with potential use in pharmaceutical and medicine. objectives: to assess the growth inhibitory effect of phyto-alkaloids, harmaline and harmine, on cancer cell lines. methods: the p. harmala l.’s alkaloids were extracted by acidic/basic extraction method and identified by two methods, fourier transform infra-red spectroscopy (ftir) and high performance liquid chromatography (hplc). two breast cancer cell lines, mda_mb_231, mcf-7, were subjected to different concentration (1–100 μg.ml-1) of the p. harmala extract at different time courses (24h, 48h, and 72 h). methylthiazol tetrazolium (mtt) test, the half maximal inhibitory concentration (ic50) and the morphological changes through optical microscopy were evaluated. results: in both studied cell lines, the p. harmala extract decreased cell viability in longer time exposure in a dose dependent manner. the more concentrated extract led to higher motility of mda-mb-231 at 24h. although, mcf-7 cell line required longer exposure time has to reach the same motility. it was observed that 30 μg.ml-1 is the minimum lethal dose that kills approximately 50% of cells at 24 hours in mda-mb-231 cell line (ic50). ic50 for mcf-7 were calculated 40 μg.ml-1 and 25 μg.ml-1 at 48 h and 72 h, respectively.  the morphological observation ensured the apoptosis nature of p. harmala on cells as their membrane kept intact and no membrane permeabilization was observed. conclusions: the results revealed that the p. harmala extracts decreased significantly growth rate and cell survival of cancer cell lines. the extract induced cell death regarding natural cell growth rate. mda-mb-231 cell line naturally has a higher growth rate than mcf-7 cell line, so higher growth inhibition of mda-mb-231 cell line by the p. harmala extract was confirmed.