New flavans, spirostanol sapogenins, and a pregnane genin from Tupistra chinensis and their cytotoxicity.

Seven new compounds, including three new flavans [tupichinol A-C (1-3)], three new spirostanol sapogenins [tupichigenin D-F (4-6)], and one new pregnane genin [tupipregnenolone (7)], together with 18 known compounds, were isolated from the underground parts of Tupistra chinensis. The structures of the new compounds were elucidated by spectroscopic analysis and chemical evidence. The structures and relative stereochemistry of 1 and 9 were further confirmed by single-crystal X-ray crystallographic analysis. Compounds Delta(25(27))-pentrogenin, 10, and ranmogenin A showed 100%, 96%, and 80% inhibition, respectively, against human gastric tumor (NUGC) cells at a concentration of 50 microM. Delta(25(27))-pentrogenin showed 100% inhibition against human nasopharyngeal carcinoma (HONE-1) cells at a concentration of 50 microM.