ABSTRACT
Aims: The aim of this study was to evaluate the in vitro cytotoxic activity and cellular effects of organic extracts and fractions of four plants; Inula viscosa, Ormenis eiriolepis (Asteraceae), Retama monosperma (Fabaceae) and Marrubium vulgare (Lamiaceae), all of them used in Moroccan traditional medicine. Methodology: The four plants were extracted using organic solvents and screened on a panel of human cancer cell lines including cell types from both solid and haematological cancer origin as well as non-transformed murine fibroblasts. Cell viability assays were performed with sixteen plant extracts. Sensitive cell lines were then exposed to increasing concentrations of the most efficient extracts in order to calculate IC50 values. Microscopy, flow cytometry and caspase activity assays were then performed in LN229, SW620 and PC-3 cell lines upon treatment to investigate the cell morphology, cell cycle distribution and cell death. Results: cell viability assays reveals that at least one extract from each plant was able to exert cytotoxic activity against the majority of cell lines tested, the IC50 values of the active extracts were in most cases ≤ 30 μg/ml. the study of the cellular effects of the most active extracts on LN229, SW620 and PC-3 cell lines shows their ability to promote cell cycle arrest and cell death. The data obtained herein support strongly the use of these plants by traditional healers for the treatment of cancer patients and could have some scientific support indicating the presence of bioactive compounds. Conclusion: The reported biological activity of these four medicinal plants used in traditional Moroccan medicine provides a starting point for forthcoming studies to determine the molecular basis of their activity and to identify the chemical compounds within the most active extracts responsible for their antitumoral effects.