Occurrence of Progesterone and Related Animal Steroids in Two Higher Plants^,

Previously, the presence of a wide variety of chemically diverse steroids has been identified in both flora and fauna. Despite the relatively small differences in chemical structures and large differences in physiological function of steroids, new discoveries indicate that plants and animals are more closely related than previously thought. In this regard, the present study gathers supporting evidence for shared phylogenetic roots of structurally similar steroids produced by these two eukaryotic taxa. Definitive proof for the presence of progesterone (3) in a vascular plant, Juglans regia, is provided. Additional evidence is gleaned from the characterization of five new plant steroids from Adonis aleppica: three 3-O-sulfated pregnenolones (6a/b, 7), a sulfated H-5β cardenolide, strophanthidin-3-O-sulfate (8), and spirophanthigenin (10), a novel C-18 oxygenated spirocyclic derivative of strophanthidin. The ab initio isolation and structure elucidation (NMR, MS) of these genuine minor plant steroids offers information on preparative metabolomic profiling at the ppm level and provides striking evidence for the conserved structural space of pregnanes and its congeners across the phylogenetic tree.