Background: Silver nanoparticles (AgNPs) have antibacterial, anti-angiogenesis and anti-cancer activity. The purpose of this study was to examine the apoptotic effects of AgNPs coated with Zataria multiflora leaves extract on HepG2 liver cancer cells.

Materials and Methods: HepG2 cancer cell lines were treated with different concentrations of AgNPs for 24 and 48 hours. The viability of the cells and inhibitory concentration (IC₅₀) were determined by the methylthiazol tetrazolium (MTT) assay. To evaluate the ability of AgNPs to induce apoptosis in HepG2 cells, the 4′,6-Diamidino-2-phenylindole dihydrochloride (DAPI), acridine orange-propidium iodide staining and flow cytometry analysis for annexin V- propidium iodide were used.

Results: The results of the MTT assay showed that AgNPs decreased the proliferation of HepG2 cells in dose- and time-dependent manner. The IC₅₀ during the incubation times of 24 and 48 hours were determined 40 and 30 &mu;g/mL, respectively (P<0.05). The results of DAPI staining showed that AgNPs can lead to break down of nuclear DNA. Moreover, the acridine orange-propidium iodide staining and annexin V-propidium iodide showed that the percentage of apoptotic cells was increased in the treated cells.

Conclusion: Silver nanoparticles covered with Z. multiflora leaf extract have the ability to induce apoptosis in cancer cells HepG2 and they can be considered as a promising strategy for the treatment of liver cancer.