Calendula arvensis L. as an anti-cancer agent against breast cancer cell lines.

Calendula arvensis L. is used in traditional folk medicine for the treatment of several diseases. Leaves, stems, and flowers of C. arvensis were extracted using a Soxhlet extractor with different solvents (i.e., hexane, chloroform, ethyl acetate, and methanol). The ethyl acetate extract of C. arvensis flowers (CAF EtOAC) had cytotoxic activity against MCF-7 and MDA-MB-231 breast cancer cells, with IC values of 70 and 78 µg/mL, respectively. Microscopic examination revealed concentration-dependent cell shrinkage, cell detachment, nuclear fragmentation, and chromatin condensation. The CAF EtOAC inhibited the migration of cultured cells in a scratch wounding assay, indicating a possible defense against metastasis. The same extract also caused apoptosis by downregulating Bcl-2 and upregulating Bax and caspase 3/7 activity. Phytochemical analyses revealed the presence of phenols and flavonoids, and gas chromatography-mass spectroscopy (GC-MS) revealed a high content of linolenic acid in the extract. Based on our data, the CAF EtOAC may provide active ingredients for the development of novel chemotherapeutics for breast cancer therapy.