Identification Of Ecdysteroids Research Articles

Small-scale analysis of phytoecdysteroids in seeds by HPLC-DAD-MS for the identification and quantification of specific analogues, dereplication and chemotaxonomy.

Phytoecdysteroids are analogues of arthropod steroids occurring in plants. They contribute to invertebrate deterrence. A wide diversity of ecdysteroids occurs in phytoecdysteroid-containing plant species, sometimes in high amounts. Ecdysteroids demonstrate potentially useful pharmaceutical actions in mammals. Establish reversed-phase high-performance liquid chromatography with tandem mass spectrometry (RP-HPLC-MS/MS) and RP-HPLC-DAD-MS (diode array detector mass spectrometry) methods for the separation, identification and quantification of ecdysteroids to screen for species containing significant amounts of 20-hydroxyecdysone (20E) and other useful ecdysteroids. Micro-extracts of seed samples (ca. 30 mg) in 50% ethanol were subjected to RP-SPE (solid-phase extraction) purification prior to analysis by RP-HPLC-MS/MS and RP-HPLC-DAD-MS. The method was initially applied to genera (Amaranthus, Centaurea, Lychnis, Ourisia, Serratula, Silene and Trollius) where high-accumulating species had been previously encountered. Seeds of 160 randomly selected species, many of which have not previously been assessed, were then analysed. HPLC-MS/MS with a short analysis time initially identifies ecdysteroid-positive extracts and quantifies 20E. The positive extracts (20 ng 20E) are then analysed by HPLC-MS/MS with a longer analysis time to identify and quantify 17 common phytoecdysteroids and, finally, HPLC-DAD-MS (0.1-0.25 μg 20E) is used to obtain UV- and MS-spectra to confirm identifications or as a basis for characterisation of partially identified or novel analogues. Lychnis coronaria, Silene fimbriata and Silene hookeri ecdysteroids are characterised for the first time and those of Cucubalus baccifer and Ipheion uniflorum are more extensively characterised. The procedure provides a rapid/sensitive method for screening small plant samples for the presence, quantification and identification of ecdysteroids. It permits ready dereplication of samples, identifying extracts containing large amounts or novel analogues.

Phytoecdysteroids from the Silene genus

Research results on the isolation and identification of ecdysteroids from plants of the Silene L. genus were presented.

Distribution of phytoecdysteroids in the Caryophyllaceae

Certain genera within the Caryophyllaceae (especially Silene and Lychnis) have received a significant amount of attention with regard to the isolation and identification of ecdysteroids. However, the taxonomy of this family is difficult. Hence, the occurrence of phytoecdysteroids in members of the Caryophyllaceae is presented, and combined with new data on ecdysteroid agonist (phytoecdysteroid) and antagonist activities, in order to survey the distribution of phytoecdysteroid-containing species within this large family, and to assess the utility of phytoecdysteroids as chemotaxonomic markers. The new data presented (representing ca. 110 species) have been obtained by the application of sensitive biological/biochemical methods for the detection of ecdysteroid agonists and antagonists, using Drosophila melanogaster B(II) bioassay and ecdysteroid-specific immunoassays. In the antagonist version of the B(II) bioassay, only weak ecdysteroid antagonist activities were detected in a few of the extracts. From both new and previously available data, it was found that phytoecdysteroids were present predominantly in the Genera Lychnis, Petrocoptis, Sagina and Silene. Comparison of ecdysteroid occurrence with a molecular phylogeny for the tribe Sileneae [Taxon 44 (1995) 525] revealed close association of ecdysteroid occurrence with certain groups of this tribe. In 14 species of Silene examined, there is a reasonable, but not absolute, relationship between the presence of ecdysteroids in the seeds and in other plant parts. Where ecdysteroids are present in the plant, highest concentrations are generally present in the roots.

Spectroscopic characterisation and identification of ecdysteroids using high-performance liquid chromatography combined with on-line UV–diode array, FT-infrared and 1H-nuclear magnetic resonance spectroscopy and time of flight mass spectrometry

A prototype multiply hyphenated reversed-phase HPLC system has been applied to the analysis of a mixture of pure ecdysteroids and an ecdysteroid-containing plant extract. Characterisation was achieved via a combination of diode array UV, 1H NMR, FT-IR spectroscopy and time of flight (TOF) mass spectrometry. This combination of spectrometers allowed the collection of UV, 1H NMR, IR and mass spectra for a mixture of pure standards enabling almost complete structural characterisation to be performed. The technique was then applied to a partially purified plant extract in which 20-hydroxyecdysone and polypodine B were identified despite incomplete chromatographic resolution and the presence of co-chromatographing interferents. The experimental difficulties in the use of such a systems for these analytes are described.

Identification of Ecdysteroids and Their Titer in the Hemolymph during Development in the Bean Bug, Riptortus clavatus (THUNBERG) (Heteroptera: Alydidae)

Identification of Ecdysteroids and Their Titer in the Hemolymph during Development in the Bean Bug, Riptortus clavatus (THUNBERG) (Heteroptera: Alydidae)

Identification of ecdysteroids of hexactinic corals

Identification of ecdysteroids of hexactinic corals

Radioimmunoassay and the Characterization of Crustacean Ecdysteroids

The development of the radioimmunoassay (RIA) for ecdysteroids has permitted the sequential measurement of circulating ecdysteroids on individual organisms. In addition, used in conjunction with various chromatographic techniques, it has assisted in the identification of ecdysteroids secreted by molting glands. The sensitivity of the assay has also permitted the monitoring of the rate of secretion of ecdysteroids by molting glands exposed to various in vitro conditions. This latter approach will be of great utility in determining the nature and effect of molt regulators (inhibitors) present in other tissues.