Chemotaxonomic significance of ecdysteroid agonists and antagonists in the Ranunculaceae: phytoecdysteroids in the genera Helleborus and Hepatica

We present here a survey of ca. 100 species within 16 genera of the family Ranunculaceae for the presence of ecdysteroid agonist and antagonist activities in methanolic seed extracts. The levels of phytoecdysteroids (agonists) have been quantified by radioimmunoassay and bioassay. A few samples possess weak antagonistic activity. Phytoecdysteroids are most prominently associated with the genus Helleborus. In this genus, species fall into two distinct classes: those with low or undetectable ecdysteroid levels and those with high ecdysteroid levels. The relationship between ecdysteroid levels and the biology of the plants in this genus is discussed. Additionally, the extract of Hepatica triloba Chaix seeds contains a significant level of phytoecdysteroids. Several other species contain low levels of phytoecdysteroids, as detected by radioimmunoassay. Together with our previous data on the genera Anemone and Pulsatilla, this survey allows us to present an overview of the distribution of ecdysteroids in this family. [Copyright &y& Elsevier]