Diastereomers of Steroidal Alkaloids with Cytotoxic Activities against Non-Small-Cell Lung Cancer from the Bulbs of Fritillaria sinica .

Eleven new steroidal alkaloids, along with nine known related compounds, were isolated from the bulbs of Fritillaria sinica . Seven pairs of diastereomers were identified, including six and four 20-deoxy cevanine-type steroidal alkaloid diastereomers with molecular weights of 413 and 415, respectively. Structures were elucidated based on spectroscopic data analysis, chemical derivatization, and single-crystal X-ray diffraction analysis. Compounds 5 , 9 , 11 , 12 , 16 , and 20 exhibited significant in vitro cytotoxic activity against non-small-cell lung cancer with CC ₅₀ values from 6.8 ± 3.9 to 12 ± 5 μM.