title: Ecdysteroids and bufadienolides from Helleborus torquatus (Ranunculaceae).
abstract: Three bufadienolides, hellebortin A (5-[beta-D-glucopyranosyloxy]-10,14,16-trihydroxy-19-nor-[5beta,10beta,14beta,16beta]-bufa-3,20,22-trienolide [1]), hellebortin B (5-[beta-D-glucopyranosyloxy]-3,4-epoxy-14-hydroxy-19-oxo-bufa-20,22-dienolide [2]) and hellebortin C (5-[beta-D-glucopyranosyloxy]-3,4-epoxy-10,14-dihydroxy-19-nor-bufa-20,22-dienolide [3]), together with 20-hydroxyecdysone 3-O-beta-D-glucoside (4) and 20-hydroxyecdysone (5) have been isolated by bioassay- and RIA-directed HPLC analyses of a methanol extract of the seeds of Helleborus torquatus. The structure and relative stereochemistry of the novel bufadienolide hellebortin A (1) and the structures of hellebortin B (2) and hellebortin C (3) were determined unambiguously by comprehensive analyses of their 1D and 2D NMR data. These five compounds are isolated from Hellborus torquatus for the first time. The biological activities of compound 1, 4 and 5 as ecdysteroid agonists and antagonists have been assessed.
authors.affiliation: Department of Biological Science, University of Exeter, Devon, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Meng
authors.forename: P
authors.initials: P
authors.lastname: Whiting
authors.forename: V
authors.initials: V
authors.lastname: Sik
authors.forename: H H
authors.initials: HH
authors.lastname: Rees
authors.forename: L
authors.initials: L
authors.lastname: Dinan
mesh_terms: D000818:Animals; D001681:Biological Assay; D002018:Bufanolides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004331:Drosophila melanogaster; D026461:Ecdysteroids; D006372:Helix, Snails / Q000201:enzymology; D006867:Hydrolases / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D019684:Magnoliopsida / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D012639:Seeds / Q000737:chemistry; D013256:Steroids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D002018:Bufanolides; D026461:Ecdysteroids; D013256:Steroids; D006867:Hydrolases