Thirty-five steroidal glycosides from Ornithogalum thyrsoides bulbs and their cytotoxicity against human leukemia cells and human small-cell lung cancer cells

The authors have previously reported several cholestane- and spirostan-type steroidal glycosides from Ornithogalum thyrsoides [ 1 ] [ 2 ] [ 3 ] [ 4 ]. Since conventional TLC analysis of the extract of O. thyrsoides bulbs suggested the presence of unprecedented compounds, a comprehensive phytochemical investigation of O. thyrsoides bulbs was conducted, which resulted in the isolation of 35 steroidal glycosides ( 1–35 ), including 21 previously undescribed ones ( 1–21 ). The structures of 1–21 were determined mainly by NMR spectroscopic analyses. The isolated compounds were classified into three distinct groups: furostan-type, spirostan-type, and cholestane-type. Although the C/D-ring junction of the steroidal skeleton is generally trans -oriented, except for certain cardiotonic and pregnane-type steroidal derivatives, 7 was revealed to possess a cis C/D-ring junction ([ Fig. 1 ]). This is the first reported instance of such a configuration in spirostan-type steroidal derivatives, marking it as a finding of significant interest. Compounds 1–35 were evaluated for cytotoxicity against HL-60 human promyelocytic leukemia cells and SBC-3 human small-cell lung cancer cells. The isolated compounds exhibited cytotoxicity in a dose-dependent manner with IC 50 values ranging from 0.000086 to 18 μM toward HL-60 cells, and from 0.00014 to 37 μM toward SBC-3 cells, respectively. Compound 19 ([ Fig. 1 ]), which demonstrated relatively potent cytotoxicity among the novel compounds, induced apoptosis in HL-60 cells, concomitant with cell cycle arrest at the G2/M phase. In contrast, 19 caused oxidative stress-associated necrosis in SBC-3 cells. These findings indicate that 19 induces cell death through distinct mechanisms of action in HL-60 and SBC-3 cells, respectively. Fig. 1 Structures of 7 and 19 . Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany