Background: Iron oxide nanoparticles are one of the most efficient metal nanoparticles, which have prominent properties in biomedical applications. In previous studies, these nanoparticles were prepared using a green synthesis method with the aqueous extract of brown seaweed (Sargassum muticum). This study aimed to examine the cytotoxic effect of these synthesized nanoparticles on A2780cp ovarian cancer cells which indicate resistance to chemotherapy regimen.

Materials and Methods: The cytotoxic effect of synthesized nanoparticles on A2780cp ovarian cancer cells were examined using the methylthiazol tetrazolium assay, acridine orange/ propodium iodide and caspase assay.

Results: Results indicated that Fe3O4 nanoparticles encapsulated in seaweed water extract possess a cytotoxic effect on ovarian cancer cells resistant to chemotherapy (IC50 values of 250 µg/ml, 125 µg/ml and 62.5µg/ml for 24, 48 and 72 h, respectively). The nanoparticles through the induction of caspase-3 and -9 dependent apoptosis (intrinsic pathway) significantly exerted a cytotoxic effect against A2780cp ovarian cancer cells.

Conclusion: The aqueous extract of brown seaweed is an appropriate candidate for stability and reduction of colloidal solution of iron oxide nanoparticles. Due to the apoptotic effect of this extract on A2780cp ovarian cancer cells, it can be a good choice for ovarian cancer treatment.