ABSTRACT
OBJECTIVE To explore the effects and potential mechanism of veratramine （VTM） on the proliferation of human glioblastoma U251 cells. METHODS The network pharmacology methods were adopted to screen the targets of ferroptosis related to the effects of VTM on glioblastoma， and to conduct gene ontology and Kyoto Encyclopedia of Genes and Genosomes enrichment analysis. Using U251 cells as the object， CCK-8 assay， the observation of cell morphological changes， DCFH-DA fluorescence probe method， FerroOrange fluorescence probe method and Western blot assay were used to validate the inhibitory effects of VTM on U251 cell proliferation and its possible mechanism. RESULTS Totally 462 targets of ferroptosis related to the effects of VTM on glioblastoma were screened out； they mainly enriched in biological processes such as oxidative stress and apoptosis， and cellular components such as cytoplasmic vesicles and mitochondrial membranes； they affected molecular functions such as iron ion （Fe2+） binding and DNA transcription processes， as well as iron death and phosphoinositide 3-kinase/protein kinase B signaling pathways. VTM with 40， 60， 80， 100， 120 and 140 μmol/L could significantly reduce the cell survival rate （P＜ 0.01）； VTM with 40， 80 and 120 μmol/L could cause cell atrophy and nuclear fragmentation， significantly inhibit the clone formation， increase the levels of intracellular reactive oxygen species （ROS） and Fe2+ levels， increase the expressions of nuclear factor-erythroid 2-related factor 2 （Nrf2） and heme oxygenase 1 （HO-1） protein to different extents， while down-regulate the expression of glutathione peroxidase 4 （GPX4） protein （P＜0.05 or P＜0.01）. CONCLUSIONS VTM can inhibit the proliferation of U251 cells， and promote the accumulation of intracellular ROS and Fe2+， thus inducing ferroptosis； its mechanism might be related to the regulation of the Nrf2/HO-1/GPX4 signaling pathway.
ABSTRACT
Objective: To study the chemical constituents of the roots and rhizomes of Veratrum grandiflorum and its antitumor activities. Methods: The compounds were isolated and purified by silica gel, C-18 reversed phase column chromatography, and their structures were identified by MS and NMR analyses. The cytotoxic activities of compounds 1-6 against HepG2 (human liver cancer cell line) were evaluated by MTT method. The effect of compound 3 on cell apoptosis of HepG2 was detected by flow cytometry. Results: Eight steroidal alkaloids were isolated and their structures were identified as (3S,15S)-3β-angeloyl-15α-acetylzygadenine (1), epirubijervine (2), veratramine (3), jervine (4), 3-angeloylzygadenine (5), veratrosine (6), veramitaline (7) and veralkamine (8). Conclusion: Compound 1 is a new alkaloid, compounds 7-8 are isolated from this plant for the first time. Compound 3 showed moderate cytotoxic activity against human tumor cell line HepG2 with IC50 value of (13.70 ± 0.99) μmol/L, and induced early apoptosis of HepG2 cells.