Steroidal components of the whole plants of Helleborus niger L. and their cytotoxicity

The genus Helleborus (Ranunculaceae) includes about 20 species, most of which are cultivated for ornamental purposes. Among them, Helleborus niger L., commonly known as Christmas rose, is native to the alpine regions of southern and central Europe. Our previous phytochemical studies on H. foetidus L. and H. lividu s Aiton ex Curtis led to the isolation of diverse steroidal compounds, some of which exhibited potent cytotoxicity in cultured tumor cells [ 1 ] [ 2 ]. Therefore, we conducted a phytochemical examination of H. niger and evaluated the cytotoxicity of the isolated compounds. The whole plants of H. niger were extracted with MeOH. The concentrated MeOH extract was passed through a Diaion HP-20 column, successively eluted with 30% MeOH, 50% MeOH, MeOH, EtOH, and EtOAc. The MeOH eluate fraction was subjected to column chromatography on silica gel and octadecylsilanized silica gel, giving compounds 1-13 ([ Fig. 1 ]). Fig. 1 Chemical structures fo 1–13 The structures of the new bufadienolide ( 1 ), bufadienolide rhamnosides ( 2 and 3 ), and ecdysteroids ( 12 and 13 ) were determined by spectroscopic studies, including 2D NMR spectral data, and chromatographic and spectroscopic analyses of the hydrolyzed products. Compounds 1–12 showed cytotoxicity against HL-60 human leukemia cells, A549 human lung adenocarcinoma cells, SBC-3 human small-cell lung cancer cells, with IC 50 values ranging from 0.0016-6.1 μM. In contrast, 13 did not show cytotoxicity. 0 Compound 2 exhibited potent cell proliferation inhibitory activity against SBC-3 cells after 24-48 h of treatment and induced apoptosis in SBC-3 cells via an intrinsic pathway after 72 h of treatment. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany