Urtica dioica (UD) has been widely used in traditional medicine due to its therapeutic benefits, including its anticancer effects. Natural compounds have a promising potential when used in combination with chemotherapeutic drugs. The present study explores the anticancer and anti-proliferative properties of UD tea in combination with cisplatin on MDA-MB-231 breast cancer cells in vitro. To elucidate the effect of this combination, a cell viability assay, Annexin V/PI dual staining, cell death ELISA, and Western blots were performed. The results showed that the combination of UD and cisplatin significantly decreased the proliferation of MDA-MB-231 cells in a dose- and time-dependent manner compared to each treatment alone. This was accompanied by an increase in two major hallmarks of apoptosis, the flipping of phosphatidylserine to the outer membrane leaflet and DNA fragmentation, as revealed by Annexin V/PI staining and cell death ELISA, respectively. DNA damage was also validated by the upregulation of the cleaved PARP protein as revealed by Western blot analysis. Finally, the increase in the Bax/Bcl-2 ratio further supported the apoptotic mechanism of death induced by this combination. Thus, a leaf infusion of Urtica dioica enhanced the sensitivity of an aggressive breast cancer cell line to cisplatin via the activation of apoptosis.
