Nowadays natural compounds are increasingly used in various fields since they cause fewer adverse side effects than their chemical counterparts. In addition, preparation and production of natural compounds are comparatively simple. The present study aimed to evaluate the anti-cancer effects of brittle star methanol extract on MCF-7 cells. Anti-cancer effects of brittle star methanol extract were examined on the MCF-7 cell line. Moreover, the toxicity of this compound was assessed using cell apoptosis methods,
ethidium bromide/acridine orange (EB/AO) staining and Annexin V Apoptosis Detection Kit. According to the MTT assay, the methanolic extract of brittle star could prevent proliferation in a time- and dose-dependent manner. The calculated inhibitory concentration that decreased the cell-viability by half (IC
50) was estimated at 150 µg/ml. On the other hand, results of EB/AO staining were indicative of increased apoptotic cells in the treatment group. In addition, results of Annexin V/PI protocol demonstrated a significant enhancement in the percentage of late apoptotic cells (29.02%) in the treatment groups (150 µg/ml) and the percentage of necrotic cells were 2.77% for a period of 24 hours. According to the results, the methanolic extract of Persian Gulf brittle star induced apoptosis in the MCF-7 cell line. These effects could be attributed to the presence of certain active biological compounds, such as Saponins, Naphthoquinones and Carotenoids. Furthermore, our findings suggested that brittle star might have beneficial effects on cancer management. Therefore, this natural marine compound could be used as a complementary element in the prevention and treatment of cancer.