Phenylboronic acid as a versatile derivatization agent for chromatography of ecdysteroids

Píš, Jaroslav; Harmatha, Juraj

doi:10.1016/0021-9673(92)85016-m

Cited by 18 publications

(1 citation statement)

References 12 publications

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“…All isolated and identified ecdysteroids, as well as their chemically modified analogues [10][11][12][13] were used for bioassays [14][15][16]19 . The new obtained minor ecdysteroids, presented in this paper, together with selected transformed analogues are scheduled 20 for ecdysteroid receptor mapping based on their interaction with the ligand-binding domain in the B II bioassay [14][15][16] . Our results, published earlier 15 , were included also into other models, using a homology modelling and docking approach 21 .…”

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Minor Ecdysteroid Components of Leuzea carthamoides

Vokáč

Budêšínský

Harmatha

2002

Collect. Czech. Chem. Commun.

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Fourteen minor ecdysteroid components were isolated and identified from the roots of Leuzea carthamoides (Willd.) DC. Two of them are new phytoecdysteroids: leuzeasterone (1) a six-member side-chain lactone, and (24Z)-29-hydroxy-24(28)-dehydromakisterone C (4) a structurally related sitostane type analogue and assumed biogenetic precursor of 1. The next one, 5α-20-hydroxyecdysone (6), is a rare A/B-ring trans-annelated epimer of the most common phytoecdysteroid 20-hydroxyecdysone. Further compounds: makisterone C (3), 3-epi-20-hydroxyecdysone (5), integristerone A (7), integristerone B (8), 22-oxo-20-hydroxyecdysone (10), taxisterone (11), rubrosterone (12), dihydrorubrosterone (13) and poststerone (14), are new constituents of L. carthamoides, though already reported as compounds isolated from other natural sources. Two earlier reported minor Leuzea ecdysteroids: the five-membered side-chain lactone carthamosterone (2) and the 11-hydroxy-substituted analogue isovitexirone (9), are also included because they are now better characterised. Certain previously described Leuzea ecdysteroids were not found in our material, which may indicate geographic, seasonal or cultivar variations.The abundant occurrence of ecdysteroids in Leuzea carthamoides DC. (syn. Rhaponticum carthamoides (Willd.) Iljin) is interesting from several viewpoints. First is the large structure variability of all so far isolated ecdysone analogues 2-8 and second is their high content in the roots or seeds of this plant 9 . L. carthamoides is endemic in Siberia, but is also cultivated as a medicinal plant on a large scale in Europe. This is why L. carthamoides can serve as a rich source of ecdysteroids, insect moulting hormone analogues,

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confidence: 99%

Minor Ecdysteroid Components of Leuzea carthamoides

Vokáč

Budêšínský

Harmatha

2002

Collect. Czech. Chem. Commun.

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Cyclic boronates in the mass spectrometry of ecdysteroids

Vaisar¹,

Píš²

1993

Rapid Comm Mass Spectrometry

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For the structural elucidation of ecdysteroids a reaction with phenylboronic acid has been employed. This reaction takes place exclusively on the C20,C22 diol moiety, thus facilitating fast and easy detection of this moiety in the molecule of ecdysteroid. This derivatization also redirects fragmentation to C17/C20 bond cleavage with charge retention on both fragments enabling assessment of the structure both of the steroid nucleus and of the side-chain. Possible reaction of phenylboronic acid with the diol moiety of the glycosyl group of the glycoside of ecdysteroid, producing di-adduct, is demonstrated; participation of the 5p-hydroxy group of 58,20-dihydroxyecdysone in the formation of such a di-adduct is discussed; and the role of the enol form of the 6-carbonyl group is proved.Ecdysteroids are polyhydroxylated steroid compounds, which take part in the regulation of developmental processes of invertebrates. Many compounds of this structural type have also been isolated from plants. ' Structure elucidation of these polyfunctional substances is usually accomplished by spectral methods, mainly nuclear magnetic resonance (NMR) and mass spectrometry because of the low amounts of the individual compounds that are available. Mass spectrometry is especially suitable because it requires only a very small amount of sample. Its combination with NMR and infra-red spectroscopy can give a large amount of information about the structure of the compound under investigation.Fast-atom bombardment (FAB) mass spectra of ecdysteroids give molecular weight information' and further information can be obtained from the spectra of daughter ions from collision-activated dissociation (CAD) in either the positive-or negative-ion m~d e .~.~ On the other hand, in an electron-impact (EI) mass spectrum the molecular ion is usually missing or is very weak, but from extensive fragmentation by sequential losses of molecules of water, cleavage of bonds C20/C22 for those compounds with a C20,C22 diol group or of bonds C17/C20 for compounds without this group as well as from steroid nucleus fragmentation, the main structural features can be Desorption chemical ionization (DCI) mass spectra can provide both molecular weight information and structural information from the extensive fragmentation that can be observed. However, in order to achieve both kinds of information it is necessary to set the experimental conditions precisely .'Another way of obtaining structural information is via the preparation of derivatives of ecdysteroids in order to change the mass spectrum in a defined way. For this purpose the derivatization reaction should fulfil the following criteria: it should be quantitative, it should produce only one product, and a mass spectrum should give information which cannot be obtained from the spectrum of an underivatized ecdysteroid. Trimethylsilylation has been used for increasing the volatility for GC/MS analysis,' while acetonides and Author to whom correspondence should be addressed. acetates have been prepared for elucidation of...

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Boronate Affinity Chromatography

Liu

Scouten

2000

Methods in Molecular Biology

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Phenylboronic acid as a versatile derivatization agent for chromatography of ecdysteroids

Cited by 18 publications

References 12 publications

Minor Ecdysteroid Components of Leuzea carthamoides

Minor Ecdysteroid Components of Leuzea carthamoides

Cyclic boronates in the mass spectrometry of ecdysteroids

Boronate Affinity Chromatography

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