Reactive oxygen species (ROS) are a crucial factor in the anticancer activity of Oliveria decumbens extract against the A431 human skin cell line.

Globally, skin cancer is a main public health challenge whose incidence is continuously increasing. Given the limitations of conventional t herapies, new research and novel therapies may be promising for reducing skin cancer morbidity and mortality. Phytochemicals are attractive resources for new therapy design in cancer research due to their cost-effectiveness and lower side effects. In the present study, the anti-cancer activity of Oliveria decumbens (O. decumbens) extract was investigated on the human skin cancer A431 cell line A431. The aqueous extract of the O. decumbens plant was prepared using the traditional method. Then IC50 was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay under different concentrations of O. decumbens. Cell apoptosis was investigated by Annexin V-FITC/Propidium Iodide (PI) and flow cytometry. Cell cycle was investigated by PI staining and flow cytometry. Reactive oxygen species (ROS) production was analyzed by DCFH-DA (2', 7' -dichlorofluorescein-diacetate) staining and flowcytometry.IC50 for cell viability was determined 475g/ml. Cell cycle analyses showed G1 arrest in treated cells compared to control cell. Results also confirmed significant increase of apoptotic cells (8.2%1, P<0.05) under IC50 concentration of the extract in comparison to the control group (2.50.99%). A significant increase in ROS level was observed in O.ecumbens treated cells compared to control cells (738 170 vs 31655 in the control group, P<0.05.).Overall, the present results indicate that O. decumbens extract can inhibit skin cancer cell proliferation via inhibition of cell cycle and apoptosis. It seems that ROS production plays a critical role in the anticancer effect of O. decumbens extract. Therefore, its potential option for future treatment of skin cancer should be considered.