Phytoecdysteroids of plants of theSilene genus and the dynamics of their accumulation

The ecdysteroids of four species of the genusSilene L. have been studied. Six ecdysteroids have been isolated and identified, and the dynamics of the accumulation of the ecdysteroids in relation to the phases of development of the plants have been determined.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 718–723, September–October, 1997.     

Phytoecdysteroids of plants of the genusSilene

Ecdysteroids produced by plants of the genusSilene are considered. The discussion covers 17 species of plants, from which 45 ecdysteroids have been isolated. It has been shown that ecdysterone is the most characteristic representative of the biosynthesis of ecdysteroids in theSilene series.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 627–635, September–October, 1993.     

Micellar capillary electrophoresis of the ecdysteroids

Summary The technique of micellar capillary electrophoresis has been applied to the separation of ecdysteroids (polyhydroxylated insect hormones) both as pure standards and in the extracts of plants and insect eggs. Succesful separations of a range of closely related ecdysteroids were obtained, however, the quality of the result was found to be critically dependent on the solvent in which the sample was applied and the degree of purity of the extracts. The technique was found to be suitable for the analysis of purified ecdysteroid-rich extracts of plants (Silene nutans, S. otites) and the eggs of the desert locust (Schistocerca gregaria). The elution order of the analytes was similar to that obtained using reversed-phase HPLC.     

New Synthesis of Ecdysteroids Based on Stigmasterol

A new synthesis of ecdysteroids from stigmasterol has been developed.     

Synthesis of (22S,23S,24S)-3β,14α,22,23-Tetrahydroxy-5α-stigmast-7-en-6-one, a New Ecdysteroid Analog

A tetrahydroxyketone that is a structural analog of ecdysteroids is synthesized from stigmasterol     

High performance liquid chromatography coupled to nuclear magnetic resonance spectroscopy and mass spectrometry applied to plant products: Identification of ecdysteroids fromSilene otites

Summary HPLC coupled in parallel to nuclear magnetic resonance (NMR) and mass spectrometry (MS) has been used to obtain¹H NMR and mass spectra of a number of ecdysteroids present in an extract of the plantSilene otites. Reversed phase gradient chromatography was performed using a D₂0-acetonitrile-based solvent system. NMR and mass spectra were obtained for integristerone A, 20-hydroxyecdysone, 2-deoxy-20-hydroxyecdysone and 2-deoxyecdysone to provide structural confirmation using continuous and stopped flow HPLC-NMR. The combined HPLC-NMR-MS system described here provided a more comprehensive analysis of the ecdysteroids present in the extract than HPLC-NMR alone.     

Ecdysteroids of a culture of tissues and cells ofAjuga turkestanica

The possibility has been studied of obtaining ecdysteroids — ecdysterone and turkesterone — with the aid of a culture of the tissues and cells of the plantAjuga turkestanica. Conditions have been selected under which the yield of ecdysteroids in the culture of tissues and cells is comparable with amounts of the same substances in the organs of the whole plant.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 51–52, January–February, 1990.     

Structure-Activity Relationship of Steroidal Insecticides. IX. Cholestane and Stigmastane 5- and 7-Bromo-6-ketosteroids

Steroids 1-16, which are intermediates in the synthesis of ecdysteroids, have been shown to possess insecticidal activity for larvae of the Colorado beetle Leptinotarsa decemlineata. Active growth- and development-regulators were found among them.     

Phytoecdysteroids of Plants of the Silene Genus. 2-Dehydroxyecdysterone-3-O-benzoate from Silene wallichiana

The known ecdysteroids 2-dehydroxyecdysone, 2-dehydroxyecdysterone, ecdysterone-22-O-benzoate, ecdysterone, integristerone A, and a new ecdysteroid identified as 2-dehydroxyecdysterone-3-O-benzoate are isolated from roots ofSilene wallichianaKlotzsch     

Effect of N-Nitroso-N-methylurea on the Biosynthetic Activity of Ajuga turkestanica Callus Tissue

The effect of N-nitroso-N-methylurea on the biosynthesis of ecdysteroids and polysaccharides has been studied. The yield of ecdysterone and water-soluble polysaccharides increases at a concentration of 8 mM.     

13C NMR Spectra of 5- and 7-Bromo-6-ketosteroids and Related Compounds

¹³ C NMR spectra have been studied and signals of C atoms have been assigned for 5- and 7-bromo-6-ketosteroids, which are intermediates in the synthesis of ecdysteroids.     

Structure-Activity Relationship of Steroidal Insecticides. VIII. Cholestane and Stigmastane Ecdysteroids and Their Structural Analogs

Structural analogs of ecdysteroids were screened for insecticidal activity for larvae of the Colorado beetle Leptinotarsa decemlineata using a contact-feed method. High activity was found for compounds 3, 6b, 7a, and 9a.     

Phytoecdysteroids of Silene viridiflora

The known ecdysteroids polipodin B, 2-deoxyecdysterone, ecdysterone, 26-hydroxypolipodin B, integristerone A, and sileneosides A and D were observed in the aerial part of Silene viridiflora L. (Caryophyllaceae). 26-Hydroxypolipodin B was observed in this species for the first time.     

Application of combined chromatographic techniques in the screening and purification of ecdysteroids

Summary Plants were found to contain ecdysteroids in concentrations in the order of 0.1% which are higher than those of the insects, and are adequate for the preparative production of ecdysteroids. A TLC screening method is elaborated for the qualitative and semiquantitative analysis of the ecdysteroid content of plants. The combined TLC method differentiates several characteristic ecdysteroids ranging from the apolar 2-deoxyecdysone to the polar 20,26-dihydroxyecdysone. A preparative purification method was developed consisting of solvent extraction, precipitation, crystallization and column liquid chromatography; these procedures permit the isolation of the main ecdysteroids in gram quantities. In some cases, droplet counter-current chromatography was also applied. Altogether, the isolation of thirteen ecdysteroids from five different plant species was accomplished by using a fast, simple and low-cost procedure, resulting in pure substances.     

Reductive Amination of ω‐Oxoecdysteroids in the Synthesis of Dimeric Ecdysteroids

N‐Alkyl‐ and N‐arylaminoecdysteroids were synthesized for the first time by reductive amination of ω‐oxoecdysteroids. By using aliphatic or aromatic diamines, dimeric ecdysteroids with an ethylenediamine or p‐phenylenediamine bridge at the C(24), C(24′)‐position of the monomeric moieties were obtained.     

Phytoecdysteroids from the <Emphasis Type="Italic">Silene</Emphasis> genus

Research results on the isolation and identification of ecdysteroids from plants of the Silene L. genus were presented.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 472–475, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Superimposition evaluation of ecdysteroid agonist chemotypes through multidimensional QSAR

The EC₅₀ values for a training set of 66 ecdysteroids and 97 diacylhydrazines were measured in the ecdysteroid-responsive Drosophila melanogaster B_II cell line, a prototypical homologous inducible gene expression system. Each of eight superimposition hypotheses for the folded diacylhydrazine conformation was evaluated and ranked on the basis of CoMFA and 4D-QSAR Q² values for the training set and R² values for a 52-member test set comprising randomly-chosen diacylhydrazines and chronologically-chosen ecdysteroids for which data became available after model construction. Both 4D-QSAR and CoMFA rate a common superimposition as the preferred one. Two additional superimpositions, with somewhat weaker 4D-QSAR and CoMFA consensus, nonetheless share several important topological features. The resultant QSAR models address the question of relative binding orientation of the two ligand families and can be useful as a virtual screen for new chemotypes.     

Sample preparation for the chromatographic determination of ecdysteroids using solid-phase extraction methods

The ecdysteroids are hormones widely distributed in insects and crustaceans, where they are involved in the regulation of moulting. Methods of sample preparation based on solid-phase extraction of the ecdysteroids from biological samples for subsequent chromatographic analysis are reviewed. Most methods use an initial partition of the sample (or extract) between water or aqueous methanol with a non-polar solvent to remove lipids. The aqueous portion is applied to a cartridge containing C₁₈-bonded silica gel. Removal of polar impurities is then effected, followed by recovery of the ecdysteroids from the cartridge and chromatographic analysis. Results are given for the use of phenylboronic acid (PBA) bonded to silica gel as a means of obtaining a much more specific method of extraction. The PBA phase was shown to have a high affinity for ecdysteroids containing a 20,22-cis-diol but not for compounds possessing only a 2,3-cis-diol.     

A Developmental Analysis of Ecdysteroids During the Metamorphosis of Drosophila Melanogaster

Abstract

A combination of ion suppression reverse phase high pressure liquid chromatography (RP-HPLC) and differential radioimmunoassay (RIA) was used to identify and quantify ecdysteroids from Drosophila melanogaster during the development of the white puparium to the adult. The whole body ecdysteroid titer revealed a large peak approximately 30 hours after pupariation. RP-HPLC-RIA analysis of the brain-ring gland complex secretion in vitro revealed the presence of: ecdysone, 20-deoxymakisterone A, and a yet uncharacterized low polarity ecdysteroid (LP-1). The metabolism of ecdysone and 20-deoxymakisterone A was followed by analysis of the ecdysteroids during development. The white puparium (0 hour) yielded a four-fold greater quantity of free 20-hydroxyecdysone and makisterone A than ecdysone and 20-deoxymakisterone A, respectively, indicating high 20-monooxygenase activity during this stage. Another metabolite of ecdysone, 20,26-dihydroxyecdysone, was present at a quantity intermediate between that of ecdysone and 20-hydroxyecdysone. Highly polar ecdysteroids (conjugates) treated with an esterase-phosphatase mixture yielded the free ecdysteroids, ecdysone, 20-deoxymakisterone A, 20-hydroxyecdysone, and makisterone A, suggesting the presence of novel ecdysteroid conjugates of 20-deoxymakisterone A and makisterone A. At 18 hours post-pupariation the levels of all free ecdysteroids were reduced when compared to the 0 hour white puparium with the highly polar ecdysteroids predominating. By 30 hour after pupariation the level of free ecdysteroids had increased, indicating net ecdysteroid synthesis. Both ecdysone and 20-deoxymakisterone A were in greater concentrations than 20-hydroxyecdysone and makisterone A, indicating a reduced level of 20-monooxygenase activity at this stage. At 48 hours post-pupariation Drosophila contained decreasing amounts of ecdysteroids except for 20,26-dihydroxy- ecdysone and low polar products. 20, 26-Dihydroxyecdysone was the only known ecdysteroid to remain at a high level during the rest of adult development.     

13C NMR of 2,3,14-Trisubstituted Δ4,7-6-Ketosteroids and Related Compounds

¹³ Spectra have been studied and signals of C atoms assigned for steroids 3-5 and 7-10, which are close structural analogs of the natural ecdysteroids 4-dehydroecdysterone 1, diaulusterol A 2, and 5,20-dihydroxyecdysone 6