Ergot Alkaloids Ergotamine Research Articles

Interaction of ergotamine with liver Cytochrome P450 3A in rats

This study was conducted to investigate the effect of the ergot alkaloid, ergotamine (ET), on the induction of CYP3A and the interaction in vivo and in vitro with ET. Sprague-Dawley rats were treated intraperitoneally for 4 days as follows: control (injecting with 0.5 ml of only corn oil); dexamethasone treatment (injecting with 100mg/kg of dexamethasone in corn oil); and ergotamine treatment (injecting with 100mg/kg of ergotamine in corn oil). Liver tissues were collected from each group (n = 5, total of 30 rats) and liver microsomes were prepared. Cytochrome CYP3A activity was evaluated using ET and its isomer as substrates in medium containing liver microsomes and NADPH at 37℃ for 30 min. HPLC was used to measure the disappearance of the substrate and the appearance of the metabolites. Liver microsomes from rats pretreated with dexamethasone were five times more (P 0.05) in activity of CYP3A when compared to the control group (5.2 vs. 7.0 nM ET/min/mg protein; SE = 4.83) or ET isomer (1.5 vs. 4.7 nM ET isomer/ min/mg protein; SE = 1.70). When ketoconazole was used as specific inhibitor of CYP3A, ergotamine metabolisms were inhibited in a dose dependent fashion reaching a maximum at an inhibitor to substrate ratio of greater than one and LD50 at 0.5 nM of ketoconazole/mg protein. The data presented in this study suggest that although the ergot alkaloids ergotamine and its isomer are ideal substrates for the isozyme CYP3A, these compounds have no effect on the induction of CYP3A after 4 days of treatment.

Indole Prenyltransferases from Fungi: A New Enzyme Group with High Potential for the Production of Prenylated Indole Derivatives

Prenylated indole derivatives are hybrid natural products containing both aromatic and isoprenoid moieties and are widely spread in plants, fungi and bacteria. Some of these complex natural products, e.g. the ergot alkaloids ergotamine and fumigaclavine C as well as the diketopiperazine derivative fumitremorgin C and its biosynthetic precursors tryprostatin A and B, show a wide range of biological and pharmacological activities. Prenyl transfer reactions catalysed by prenyltransferases represent key steps in the biosynthesis of these compounds and often result in formation of products which possess biological activities distinct from their non-prenylated precursors. Recently, a series of putative indole prenyltransferase genes could be identified in the genome sequences of different fungal strains including Aspergillus fumigatus. The gene products show significant sequence similarities to dimethylallyltryptophan synthases from fungi. We have cloned and overexpressed six of these genes, fgaPT1, fgaPT2, ftmPT1, ftmPT2, 7-dmats and cdpNPT from A. fumigatus in E. coli and S. cerevisiae. The overproduced enzymes were characterised biochemically. Three additional prenyltransferases, DmaW-Cs, TdiB and MaPT were identified and characterised in a Clavicipitalean fungus, Aspergillus nidulans and Malbranchea aurantiaca, respectively. Sequence analysis and alignments with known aromatic prenyltransferases as well as phylogenetic analysis revealed that these enzymes belong to a new group of "aromatic prenyltransferases". They differ clearly from membrane-bound aromatic prenyltransferases from different sources and soluble prenyltransferases from bacteria. The characterised enzymes are soluble proteins, catalyse different prenyl transfer reactions on indole moieties of various substrates and do not require divalent metal ions for their enzymatic reactions. All of the enzymes accepted only dimethylallyl diphosphate as prenyl donor. On the other hand, they showed broad substrate specificity towards their aromatic substrates. Diverse tryptophan derivatives and tryptophan-containing cyclic dipeptides were accepted by these enzymes, providing a new strategy for convenient production of biologically active substances, e.g. by chemoenzymatic synthesis.

Management of Nonobstetric Pain During Pregnancy and Lactation

Management of Nonobstetric Pain During Pregnancy and Lactation

Management of nonobstetric pain during pregnancy and lactation.

Management of nonobstetric pain during pregnancy and lactation.

ChemInform Abstract: CONFORMATIONAL ANALYSIS OF THE ERGOT ALKALOIDS ERGOTAMINE AND ERGOTAMININE

Conformational analyses by 1H NMR and potential-energy calculations are reported for the ergot alkaloids ergotamine and ergotaminine, both as free bases and as the protonated species. In the neutral forms in CDCl3. two strong intramolecular hydrogen bonds fix the molecules in folded conformations, but the protonated species adopt a more extended conformation, with a single intramolecular hydrogen bond. Of the 24 alternative conformations available to ergotamine, the most likely biologically active species in environments with low dielectric constants, e.g., the presumed ergotamine binding site, is the folded, hydrogen-bonded conformation observed for the neutral molecule in CDCl3 solution.

Conformational analysis of the ergot alkaloids ergotamine and ergotaminine.

Conformational analyses by 1H NMR and potential-energy calculations are reported for the ergot alkaloids ergotamine and ergotaminine, both as free bases and as the protonated species. In the neutral forms in CDCl3. two strong intramolecular hydrogen bonds fix the molecules in folded conformations, but the protonated species adopt a more extended conformation, with a single intramolecular hydrogen bond. Of the 24 alternative conformations available to ergotamine, the most likely biologically active species in environments with low dielectric constants, e.g., the presumed ergotamine binding site, is the folded, hydrogen-bonded conformation observed for the neutral molecule in CDCl3 solution.

Radioimmuntests für die Bestimmung der Peptidealkaloide Ergotamin und Ergocristin in Claviceps purpurea

Radioimmunoassays for the separate and quantitative determination of the peptide ergot alkaloids ergotamine and ergocristine were developed. The alkaloids were coupled covalently to bovine serum albumin and antibodies were raised in rabbits. 3H-labelled tracers were used. The antibodies exhibited high specificity and affinity towards these alkaloids [Ka = 0.15 × 109l/mol (ergocristine); Ka = 1.32 × 109 l/mol (ergotamine)]. Simple lysergic acid derivatives and clavines did not cross react. The measuring range was between 3.5-86 pmol (2-50 ng) of ergotamine and 0.8-33 pmol (0.5-20 ng) of ergocristine. With this assay the alkaloid distribution in sclerotia of Claviceps purpurea (Fries) Tulasne was determined, and the time course of alkaloid formation in parasitic Claviceps cultures was followed. Alkaloid rich sclerotia were selected from natural sources and successfully used in the establishment of high alkaloid yielding parasitic strains.