Saponin Fractions from Eryngium planum L. Induce Apoptosis in Ovarian SKOV-3 Cancer Cells

(1) The cytotoxicity and antioxidant activity of different fractions as well as the pro-apoptotic activity of saponin fractions from Eryngium planum L. in SKOV-3 was investigated. (2) In screening studies, the cytotoxicity of six fractions on SKOV-3 was examined by LDH and SRB assays. The most active fractions—triterpenoid saponins—were selected for further investigation. To determine the mechanism of saponin fractions’ cytotoxicity, their ability to induce apoptosis was examined via Annexin V assay. The effect of the saponin fractions on caspase 3 activity was measured using a Caspase 3 Assay Kit. The expression of 84 apoptosis-related genes was investigated in cancer cells exposed to saponin fractions from the roots. The radical scavenging capacity of different fractions was determined via DPPH assay. (3) The pronounced cytotoxic effects in SKOV-3 were demonstrated by saponin fractions from the leaves and roots. Those saponin fractions were chosen for further investigation. The treatment of cancer cell lines with saponins obtained from the roots provoked a significant increase in apoptotic cells. In the SKOV-3 cells, saponins caused upregulation of pro-apoptotic genes and a decrease in anti-apoptotic genes. The activation of caspase 3 was correlated with an increased DFFA expression level in the treated SKOV-3 cells. The most active fractions were phenolic acids from the shoots and roots. (4) To the best of our knowledge, the current study is the first to demonstrate that the barrigenol-type triterpenoid saponin fraction from the roots of E. planum inhibits SKOV-3 cell proliferation and induces apoptosis, which may be regulated by the expression of genes mostly specific to a mitochondria-related pathway.