Cytotoxicity, in vivo toxicity, and chemical composition of the hexane extract of Plectranthus amboinicus (Lour.) Spreng.

Cancer is a universal health issue, and many anticancer therapeutic drugs have been isolated from natural products. This study analyzed the cytotoxic and apoptotic activity of Plectranthus amboinicus leaf hexane (PALH) extract in MDA-MB-231 (median inhibitory concentration [IC50] = 39.26 µg/mL) and MCF7 (IC50 = 89.05 µg/mL) breast cancer cell lines. Cells appeared rounded and shrunken, indicating morphological changes due to apoptosis induction. The primary constituent of PALH was phenol, 5-methyl-2-(1-methylethyl) (44%). PALH extract treatment increased the percentage of late apoptotic cells in the MDA-MB231 cell line (58% ± 1.5% at 200 µg/mL) compared to the control group, as evidenced by the activated caspase-3 and caspase-7 identified and captured by fluorescence microscopy. The relative migration rate in MDA-MB-231 cells treated with 10 µg/mL of PALH extract for 48 h was significantly lower compared to the control group. Analysis of acute (2000 mg/kg/BW) and subacute (250 and 500 mg/kg/BW) toxicity of PALH extract in mice showed no mortality or adverse effects in the kidney and liver histology compared to the control group. PALH extract can be considered nontoxic as it does not cause any adverse changes and so can be proposed as a potential breast anticancer agent.

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 IC50 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.