Cytotoxic effect of zinc oxide phytonanoparticles and Bonellia macrocarpa (Cav.) B. Stahl & Källersjö extract on breast cancer cell lines

This study focused on the synthesis of zinc oxide (ZnO) phytonanoparticles (PNPs) using Bonellia macrocarpa root extract and the evaluation of their cytotoxic activity in three cancer cell lines and the non-tumor control HaCaT cells. The PNPs were characterized using UV–Vis spectrophotometry, Fourier-transform infrared spectroscopy (FT-IR), particle analyzer, and scanning electron microscopy (SEM). The cytotoxic activity of ZnO PNPs was evaluated in the breast cancer cell lines MDA-MB-468, MDA-MB-231, and MCF-7. The results demonstrated a significant antiproliferative effect, particularly in the MDA-MB-468 cell line with an IC₅₀ of 34 ppm, along with increased selectivity for this cell line compared to the crude extract and the reference drug, doxorubicin. Furthermore, the PNPs also reduced both the formation and size of tumor cell colonies and suppressed cell migration in the MDA-MB-468 line. These effects indicate a significant impact on the growth and spread of cancer cells. Moreover, PNPs successfully internalized into the cancer cells and induced a significantly higher overproduction of reactive oxygen species (ROS) compared to doxorubicin and the crude extract from B. macrocarpa roots. Finally, PNPs were observed to induce apoptosis in MDA-MB-468 cells, suggesting activation of programmed cell death pathways. The synthesis of PNPs offers an alternative for obtaining nanoscale structures with significant potential to reduce the progression of breast cancer. This approach may complement and enhance existing therapies for this disease.