Abstract
An activity-guided isolation study on the EtOH extract prepared from the bulbs of Prospero autumnale yielded four new phenolic compounds, including a new stilbenoid (1), a new homoisoflavonoid derivative (8), a new homoisoflavonoid dimer (9), and an unprecedented homoisoflavone-stilbene heterodimer (10), together with six known (2-7) analogs. Their chemical structures were elucidated by spectroscopic analysis and theoretical NMR and ECD calculations. Compounds 9 and 10 are unique in their scaffolds. The in vitro cytotoxic activity of purified compounds was evaluated against eight tumor cell lines (HCT116, LoVo, DU145, PC3, HEP3B, HEPG2, MCF7, and MDA-MB-231) and one nontumor cell line (L929) by the MTS assay. Compounds 1, 2, 4, and 10 exhibited inhibition with IC50 values ranging from 8.2 to 37.6 μM. Cytotoxic cell death mechanisms were further investigated, indicating variability in apoptosis, necrosis, or cell cycle arrest.