Twelve New Seco-Pregnane Glycosides from Cynanchum taihangense .

For our interest in the potential biologically active and structurally unique steroidal glycosides, continued phytochemical investigation of Cynanchum taihangense was carried out; twelve new seco-pregnane glycosides, cynataihosides I-L ( 1 - 4 ), M-T ( 7 - 14 ), and two known glycosides, glaucoside A ( 5 ) and atratcynoside F ( 6 ), were isolated from the 95% ethanol extract of Cynanchum taihangense . Two new aglycones were found among compounds 10 , 11 , 13 , and 14 . The structures of the glycosides were elucidated based on 1D and 2D NMR spectroscopic data, HR-ESI-MS analysis, and chemical evidence. The cytotoxicity of compounds against three human tumor cell lines (HL - 60, THP-1, and PC-3) were evaluated by MTT assay. Compound 11 displayed significant cytotoxicity against THP-1 and PC-3 cell line with IC ₅₀ values of 5.08 and 22.75 μm, respectively. Compounds 3 and 14 exhibited moderate and selective cytotoxicity on HL - 60 and THP-1 with IC ₅₀ values of 17.78 and 16.02 μm, respectively.