Novel Oleanane-Type Triterpene Glycosides from the Saponaria officinalis L. Seeds and Apoptosis-Inducing Activity via Mitochondria

Abstract

Saponaria officinalis L., commonly known as “Soapwort”, is a rich source of triterpene glycosides; however, the chemical constituents of S. officinalis seeds have not been fully identified. In this study, we conducted a systematic phytochemical investigation of the seeds of S. officinalis and obtained 17 oleanane-type triterpene glycosides (1–17), including seven new glycosides (1–7). The structures of 1–7 were determined based on a detailed analysis of NMR spectroscopic data and chromatographic and spectroscopic analyses following specific chemical transformation. The cytotoxicities of the isolated compounds were evaluated against HL-60 human promyelocytic leukemia cells, A549 human adenocarcinoma lung cancer cells, and SBC-3 human small-cell lung cancer cells. The cytotoxicities of 1, 4, and 10 toward HL-60 cells and SBC-3 cells were nearly as potent as that of cisplatin. Compound 1, a bisdesmosidic triterpene glycoside obtained in good yield, arrested the cell cycle of SBC-3 cells at the G2/M phase, and induced apoptosis through an intrinsic pathway, accompanied by ROS generation. As a result of the mitochondrial dysfunction induced by 1, mitochondria selective autophagy, termed mitophagy, occurred in SBC-3 cells.

Structure Elucidation of 16 Undescribed Steroidal Glycosides from the Underground Parts of Agapanthus africanus and Apoptosis-Inducing Activity in Small-Cell Lung Cancer Cell

“…After incubation with each test sample for 72 h, the cell viability was measured with the MTT assay method as previously described. 26 A dose–response curve was plotted for each compound, 1 – 3 , 10 , 13 , and 14 , which inhibited cell growth by more than 50% at sample concentrations of 50 μM, and the concentrations at which 50% inhibition (IC 50 ) of cell growth occurred were calculated. The cell growth inhibition of SBC-3 cells (cell concentration: 5 × 10 4 cells/mL) exposed to 1 for 24 h was elucidated by the same method as above ( Table 8 ).…”

“…SBC-3 cells (cell concentration: 5 × 10 5 cells/mL) were cultured in a six-well flat-bottom plate and treated with EtOH/H 2 O (1:1), 10 μM cisplatin, or 15 μM 1 for 24 h. The Western blotting analysis was carried out by the same procedures as previously reported. 26 The following antibodies were recruited: β-actin (8H10D10 Mouse mAb, product number 3700, 1:1000; Cell Signaling Technology, Danvers, MA, USA), caspase-8 (1C12 Mouse mAb, product number 9746, 1:1000; Cell Signaling Technology), caspase-9 (C9 Mouse mAb, product number 9508, 1:2000; Cell Signaling Technology), caspase-3 (3G2 Mouse mAb, product number 9668, 1:1000, Cell Signaling Technology), PARP (46D11 Rabbit mAb, product number 9532, 1:1000; Cell Signaling Technology), Bax (2D2 Mouse mAb, product number 89477, 1:1000; Cell Signaling Technology), Bcl-2 (124 Mouse mAb, product number 15071, 1:1000; Cell Signaling Technology), anti-rabbit IgG, horseradish peroxidase (HRP)-linked antibody (product number 7074, 1:10000; Cell Signaling Technology), and anti-mouse IgG, HRP-linked antibody (product number 7076, 1:10000; Cell Signaling Technology). The signals were detected using ECL Prime Western Blotting Detection Reagents (GE Healthcare, Boston, MA, USA), and photographed by a LAS-3000 luminescent image analyzer (FUJIFILM, Tokyo, Japan).…”

“…SBC-3 cells (cell concentration 5 × 10 5 cells/mL) were cultured in a six-well flat-bottom plate and preincubated for 24 h. Then, SBC-3 cells were treated with EtOH/H 2 O (1:1), 5 mM NAC, 50 μM TBHP, 10 μM cisplatin, or 15 μM 1 for 3, 6, 12, and 24 h. The ROS generation levels were measured using the same methods as previously described. 26 The ROS generation levels were evaluated using a BD FACSCelesta flow cytometer.…”

“…SBC-3 cells (cell concentration: 5 × 10 5 cells/mL) were cultured in a six-well flat-bottom plate and treated with EtOH/H 2 O (1:1), 10 μM cisplatin, or 15 μM 1 for 24 h. The Western blotting analysis was carried out by the same procedures as previously reported. 26 The following antibodies were recruited: β-actin (8H10D10 Mouse mAb, product number 3700…”

“…potential was detected by the same procedures as previously described. 26 Finally, SBC-3 cells were analyzed using a BD FACSCelesta flow cytometer. Evaluation of ROS Generation Level.…”