Preparative-scale chromatography of ecdysteroids: a class of biologically active steroids

A simple separation procedure is developed for the isolation of the main phytoecdysteroid 20-hydroxyecdysone from the herb Silene viridiflora. The purification in four steps uses only a simple preparative-scale separation technique (i.e., liquid-liquid extraction, precipitation, solid-phase extraction on octadecyl silica, and crystallization). This procedure is extended using classical normal-phase liquid column chromatography, rotation planar chromatography, and preparative high-performance liquid chromatography for the isolation of the minor ecdysteroids: integristerone A, 26-hydroxypolypodine B, 2-deoxy-20,26-dihydroxyecdysone, and polypodine B. 2-Deoxy-20,26-dihydroxyecdysone is isolated from this species for the first time. The isolation of these ecdysteroids in adequate amounts makes them readily available for insect physiology experiments and for structure-activity relationship studies. The preparative-scale separation work also results in a minor, as yet unknown ecdysteroid.