Cytotoxic and antiproliferative activity of <i>Helichrysum arenarium</i> (Asteraceae) extract against tumor cell lines

For the first time, the presence of cytotoxic and antiproliferative activity in the Helichrysum arenarium (L.) Moench extract and its ability to induce apoptosis in human tumor cell lines Jurkat, MCF-7, SK-BR-3, A549, PC-3, HCT-116, A498 was revealed. After 24 hours of incubation in the extract (0.9 mg/ml), cells in early apoptosis (from 36.1% in the A549 line to 49.2% in the HCT-116 line) and late apoptosis (from 11.7% in the HCT-116 line to 37.7% in the MCF-7 line) were detected. Different cell lines exhibit different sensitivity response: early apoptosis predominated in some, while late apoptosis or even complete cell destruction prevailed in others. Under the effect of H. arenarium extract, caspase-dependent apoptosis which is induced through caspase-3, was established in the Jurkat line. More than 11% of cells killed by apoptosis were observed in cell lines A549, PC-3, HCT-116, and MCF-7 when incubated in 0.9 mg/mL extract. The extract of H. arenarium showed maximum activity on A498 cells at a semi-lethal concentration of 7.2 mg/mL: in the first 24 h of exposure, cytotoxic and cytostatic activity, and a decrease in the cell’s ability to cytoprotective autophagy were detected; after 48 h the extract retained only cytostatic activity.