Pregnane glycosides from the bark of Marsdenia cundurango and their cytotoxic activity.

Seven new pregnane glycosides (1-7) and eight known compounds (8-15) were isolated from the bark of Marsdenia cundurango (Asclepiadaceae). The structures of 1-7 were determined by spectroscopic analysis, including two-dimension NMR spectroscopy, chemical transformations, and chromatographic analysis of the hydrolyzed products. The isolated compounds 1-15 were evaluated for their cytotoxic activity against HL-60 human leukemia cells, A549 human lung adenocarcinoma cells, and TIG-3 normal human lung cells, including apoptosis-inducing activity of a representative pregnane glycoside in HL-60 cells.