ABSTRACT
Methanolic extracts of seeds of several (Carex species were found to antagonise the action of 20-hydroxyecdysone in the Drosophila melanogaster microplate-based B(II) cell bioassay. Bioassay-guided HPLC analysis of seeds of Carex pendula (drooping sedge) provided one previously unknown tetrastilbene (cis-miyabenol A) and two known oligostilbenes (kobophenol B and cis-miyabenol C) as the biologically active compounds (EC50 values were 31, 37 and 19 microM, respectively, vs. 5 x 10(-8) M 20-hydroxyecdysone). The structures and relative stereochemistries of these compounds were deduced by comprehensive ID- and 2D-NMR experiments. These compounds are isolated from Carex pendula for the first time. In vitro experiments with dipteran and lepidopteran ecdysteroid receptor proteins demonstrate that the oligostilbenes are able to compete with radiolabelled ecdysteroid ([3H]ponasterone A) for occupancy of the ligand binding site. IC50/Ki values are similar to the EC50 values obtained in the B(II) bioassay.
Subject(s)
Ecdysterone/analogs & derivatives , Ecdysterone/pharmacology , Magnoliopsida/chemistry , Receptors, Steroid/physiology , Seeds/chemistry , Steroids/antagonists & inhibitors , Stilbenes/pharmacology , Animals , Biological Assay , Chromatography, High Pressure Liquid , Diptera , Drosophila melanogaster , Ecdysteroids , Ecdysterone/antagonists & inhibitors , Ecdysterone/pharmacokinetics , Lepidoptera , Magnoliopsida/classification , Receptors, Steroid/antagonists & inhibitors , Receptors, Steroid/drug effects , Species Specificity , Steroids/agonists , Stilbenes/chemistry , Stilbenes/isolation & purificationABSTRACT
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.
Subject(s)
Bufanolides/chemistry , Magnoliopsida/chemistry , Steroids/chemistry , Animals , Biological Assay , Bufanolides/isolation & purification , Bufanolides/pharmacology , Cell Line , Cell Survival/drug effects , Chromatography, High Pressure Liquid , Drosophila melanogaster , Ecdysteroids , Helix, Snails/enzymology , Hydrolases/metabolism , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Conformation , Molecular Structure , Seeds/chemistry , Steroids/isolation & purification , Steroids/pharmacologyABSTRACT
A new ecdysteroid glycoside, limnantheoside C (20-hydroxyecdysone 3-O-beta-D-glucopyranosyl-[-->3]-beta-D-xylopyranoside [1]), together with limnantheoside A (20-hydroxyecdysone 3-O-beta-D-xylopyranoside [2]) and 20-hydroxyecdysone (3) have been isolated by bioassay/RIA-directed HPLC analyses of a methanol extract of the seedmeal of Limnanthes alba Hartw. ex Benth. The structure of the novel ecdysteroid glycoside (1) was determined unambiguously by UV, LSIMS and a combination of 1D- and 2D-NMR experiments. These three compounds are isolated from Limnanthes alba for the first time.
Subject(s)
Brassicaceae/chemistry , Ecdysone/chemistry , Ecdysteroids/chemistry , Glycosides/chemistry , Saponins/chemistry , Seeds/chemistry , Animals , Cell Line , Drosophila melanogaster/drug effects , Ecdysone/analogs & derivatives , Ecdysone/isolation & purification , Ecdysteroids/pharmacology , Glycosides/pharmacology , Models, Molecular , Molecular Structure , Radioimmunoassay , Saponins/isolation & purificationABSTRACT
Seeds of Rhagodia baccata afforded, in addition to 20-hydroxy-ecdysone and polypodine B, a novel phytoecdysteroid, (20R)-22-deoxy-20,21-dihydroxyecdysone, the structure of which was elucidated unequivocally by UV, LSIMS and NMR techniques. This compound possessed agonistic activity in the Drosophila melanogaster BII cell bioassay, with an ED50 value of 2.0 x 10(-7)M (ED50 value for 20-hydroxyecdysone = 7.5 x 10(-9)M). The distribution of ecdysteroids in plants of R. baccata has been determined. Highest levels are associated with the youngest aerial tissues and with the roots. Ecdysteroid profiles are qualitatively very similar throughout the plant, with 20-hydroxyecdysone and polypodine B predominating in all plant parts tested.
Subject(s)
Chenopodiaceae/chemistry , Ecdysone/analogs & derivatives , Steroids/chemistry , Animals , Ecdysteroids , Plant Extracts , Seeds , Steroids/isolation & purification , Steroids/metabolismABSTRACT
Bioassay/RIA-directed phytochemical examination of the seeds of Axyris amaranthoides afforded a new ecdysteroid: 1 alpha,20R-dihydroxyecdysone [1-epi-integristerone A], together with 20-hydroxyecdysone and polypodine B. The structure of 1 alpha,20R-dihydroxyecdysone was determined unequivocally by UV, LSIMS, and a combination of 1D and 2D NMR techniques.
Subject(s)
Ecdysone/analogs & derivatives , Plants/chemistry , Ecdysone/chemistry , Ecdysone/isolation & purification , Magnetic Resonance Spectroscopy , Molecular Structure , Radioimmunoassay , Spectrometry, Mass, Secondary Ion/methods , Spectrophotometry, UltravioletABSTRACT
Bioassay-assisted HPLC analyses yielded two prieurianin-type limonoids, prieurianin and rohitukin, from the seeds of Turraea obtusifolia, which act as antagonists of 20-hydroxyecdysone action in the Drosophila melanogaster BII cell line. With a 20-hydroxyecdysone concentration of 5 x 10(-8) M, the ED50 values for prieurianin and rohitukin are 10(-5) M and 1.25 x 10(-4) M, respectively.