Studies on differentiation inducers. IV. Pregnane derivatives from condurango cortex.

In connection with the study of differentiation inducers from plants, the methanol extract of Condurango Cortex (bark of Marsdenia condurango REICH, Asclepiadaceae) was investigated to examine its differentiation-inducing activity towards mouse myeloid leukemia (M1) cell line. Six pregnane glycosides, including three new compounds, were isolated as differentiation inducers. Each of the six active glycosides has three or four deoxylated sugars which are well-known to occur in Asclepiadaceae plants. M1 cells were differentiated into phagocytic cells by these glycosides, and they were found to be more effective than their aglycones. Condurangoglycosides A (7) and C (8), having a cinnamoyl group in their aglycones, were the most potent differentiation inducers and M1 cells became phagocytic cells after 24 h treatment with these compounds.