Dubrovay Z.,Spectroscopic Research |
Dubrovay Z.,NMR Laboratory |
Hada V.,Spectroscopic Research |
Hada V.,MS Laboratory |
And 3 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2013
In the course of exploring the possibilities of developing a new, improved process at Gedeon Richter for the production of the "bisindole" alkaloids vinblastine (VLB) and vincristine (VCR), some novel VLB/VCR-related trace impurities were detected by analytical HPLC. Following isolation by preparative HPLC, a combination of 1D and 2D ultra high-field NMR and high-resolution (HR) (LC-)MS/MS studies allowed the structural identification and complete spectral characterization of several hitherto unpublished VLB/VCR-analogue impurities. Since the impurities could not be isolated in entirely pure forms and were available only in minute, mass-limited quantities, accessing the spectral information needed for their ab initio structure determination was met with various practical difficulties. Successful structure determination therefore relied heavily on the availability and use of detailed and definitive spectral data for both VLB and VCR. In particular, the utilization of detailed 1H, 13C, and 15N NMR assignments as well as 1H-1H, 1H-13C and 1H-15N spin-spin connectivities pertaining to different solvents for VLB/VCR base and sulphate salt was required. Although NMR studies on VLB base and other bisindoles were reported earlier in the literature, an NMR characterization of VLB and VCR under the above-mentioned circumstances and using ultra-high field instrumentation is either scarcely available or entirely lacking, therefore the necessary data had to be obtained in-house. Likewise, a modern tandem HR-ESI-MS/MSn fragmentation study of VLB and VCR has not been published yet. In the present paper we therefore give a thorough NMR and MS characterization of VLB and VCR specifically with a view to filling this void and to provide sufficiently extensive and solid reference data for the structural investigation of the aforementioned VLB/VCR impurities. Besides being scientifically relevant in its own right, the disclosed data should be useful for anyone interested in VLB/VCR-related molecules at a structural level. © 2012 Elsevier B.V.
Veszelka S.,Hungarian Academy of Sciences |
Toth A.E.,Hungarian Academy of Sciences |
Walter F.,Hungarian Academy of Sciences |
Kittel A.,Hungarian Academy of Sciences |
And 8 more authors.
European Journal of Pharmaceutics and Biopharmaceutics | Year: 2012
An accurate means of predicting blood-brain barrier (BBB) penetration and blood-brain partitioning of NCEs (new chemical entities) would fulfill a major need in pharmaceutical research. Currently, an industry-standard BBB drug penetration model is not available. Primary brain capillary endothelial cells, optionally co-cultured with astrocytes and/or pericytes, are the most valued models of BBB. For routine use, establishing and maintaining a co-culture system is too costly and labor intensive. Alternatively, non-cerebral cell lines such as MDCK-MDR1 are used, and most recently, the suitability of native and modified Caco-2 for predicting brain penetration has also come under investigation. This study provides comparative data on the morphology and functionality of the high integrity brain capillary endothelial BBB model (EPA: triple culture of brain capillary endothelial cells with pericytes and astrocytes) and the epithelial cell-based (native Caco-2, high P-glycoprotein expressing vinblastine-treated VB-Caco-2 and MDCK-MDR1) surrogate BBB models. Using a panel of 10 compounds VB-Caco-2 and MDCK-MDR1 cell lines show restrictive paracellular pathway and BBB-like selective passive permeability that makes them comparable to the rat brain BBB model, which gave correlation with the highest r2 value with in vivo permeability data. In bidirectional assay, the VB-Caco-2 and the MDCK-MDR1 models identified more P-glycoprotein drug substrates than the rat brain BBB model. While the complexity and predictive value of the BBB model is the highest, for the screening of NCEs to determine whether they are efflux substrates or not, the VB-Caco-2 and the MDCK-MDR1 models may provide a simple and inexpensive tool. © 2012 Elsevier B.V. All rights reserved.
PubMed | Spectroscopic Research, Steroid Synthetic Laboratory and Research Analytics
Type: | Journal: Journal of pharmaceutical and biomedical analysis | Year: 2014
Herein we discuss the structure elucidation of an unknown peak detected by HPLC in the active pharmaceutical ingredient ulipristal acetate during analytical method development. An extensive chromatographic, MS and NMR spectroscopic study gave the surprising result that the detected component is the natural-abundance mono-deuterium isotopologue of the API. To the best of our knowledge this is the first example where such a mono-deuterium isotopologue could be resolved from its mother component by HPLC and structurally fully characterized by NMR and MS. The reason for this separation could be rationalized in terms of some special structural features of the molecule.
Jablonkai E.,Budapest University of Technology and Economics |
Henyecz R.,Budapest University of Technology and Economics |
Milen M.,Budapest University of Technology and Economics |
Koti J.,Spectroscopic Research |
Keglevich G.,Budapest University of Technology and Economics
Tetrahedron | Year: 2014
A few phosphinic acids, such as phenylphosphinic acids, 1-hydroxy-3-phospholene 1-oxides and 1-hydroxyphospholane oxides are esterified with simple alcohols in the presence of propylphosphonic anhydride (T3P®). If 1.1 equiv of the T3P® reagent is used, the esterifications are fast and efficient at 25° C. In the case of more reactive models it was enough to apply 0.66 equiv of T3P® at 85°C under microwave conditions. The amidation of 1-hydroxy-3-methyl-3-phospholene oxide could also be accomplished under similar conditions. © 2014 Elsevier Ltd. All rights reserved.
PubMed | Compound Profiling Laboratory, Spectroscopic Research and Budapest University of Technology and Economics
Type: | Journal: Journal of pharmaceutical and biomedical analysis | Year: 2016
The linkage between the central nervous system availability and neuropharmacological activity of the constituents of Ginkgo biloba L. extracts (GBE) is still incomplete. In this study, the in vitro blood-brain barrier (BBB) permeability profile of the standardised GBE was investigated by the parallel artificial membrane permeability assay (PAMPA). Biomarkers, such as terpene trilactones, flavonoid aglycones and ginkgotoxin exerted moderate or good BBB-permeability potential (BBB+), while glycosides and biflavones were predicted as unable to pass the BBB. N-methyltyramine (NMT) and N,N-dimethyltyramine or hordenine (Hor) were identified among BBB+ compounds, while subsequent direct HRMS analysis revealed tyramine (Tyr) and N,N,N-trimethyltyramine or candicine (Can) in GBE as trace constituents. Distribution of Tyr, NMT, Hor and Can was determined by a validated ion-exchange mechanism-based liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method in G. biloba samples, such as herbal drugs and dietary supplements. The total content of the four tyramine derivatives in various GBEs ranged from 7.3 up to 6357g/g dry extract with NMT and Hor as most abundant ones. Considering the pharmacological activities and the revealed fluctuation in the concentration of the analysed adrenergic protoalkaloids, the presented rapid LC-ESI-MS method is proposed for monitoring of the levels of Tyr, NMT, Hor and Can in G. biloba products.
Simon A.,Budapest University of Technology and Economics |
Vanyolos A.,University of Szeged |
Beni Z.,Spectroscopic Research |
Dekany M.,Spectroscopic Research |
And 2 more authors.
Steroids | Year: 2011
Three new compounds (3, 7, and 11) together with eight known phytoecdysteroids (1, 2, 4-6, and 8-10) were isolated from the rhizomes of common polypody, Polypodium vulgare L. The structures of compounds were elucidated by spectroscopic methods including 1D and 2D NMR measurements. The 1H and 13C NMR assignments of compounds 1, 6, 9 and 10 are included. © 2011 Elsevier Inc. All rights reserved.
Marosi A.,Semmelweis University |
Szalay Z.,Drug Polymorphism Research |
Beni S.,Semmelweis University |
Szakacs Z.,Spectroscopic Research |
And 4 more authors.
Analytical and Bioanalytical Chemistry | Year: 2012
Multinuclear one (1D-) and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopic investigations of famotidine, the most potent and widely used histamine H 2-receptor antagonist, were carried out in dimethyl sulfoxide-d 6 (DMSO-d 6) and water. Previous NMR assignments were either incomplete or full assignment was based only on 1D spectra and quantum-chemical calculations. Our work revealed several literature misassignments of the 1H, 13C, and 15N NMR signals and clarified the acid-base properties of the compound at the site-specific level. The erroneous assignment of Baranska et al. (J. Mol. Struct. 2001, 563) probably originates from an incorrect hypothesis about the major conformation of famotidine in DMSO-d 6. A folded conformation similar to that observed in the solid-state was also assumed in solution, stabilized by an intramolecular hydrogen bond involving one of the sulphonamide NH 2 protons and the thiazole nitrogen. Our detailed 1D and 2D NMR experiments enabled complete ab initio 1H, 13C, and 15N assignments and disproved the existence of the sulphonamide NH hydrogen bond in the major conformer. Rather, the molecule is predominantly present in an extended conformation in DMSO-d 6. The aqueous acid-base properties of famotidine were studied by 1D 1H- and 2D 1H/ 13C heteronuclear multiple-bond correlation (HMBC) NMR-pH titrations. The experiments identified its basic centers including a new protonation step at highly acidic conditions, which was also confirmed by titrations and quantum-chemical calculations on a model compound, 2-[4-(sulfanylmethyl)-1,3-thiazol-2-yl]guanidine. Famotidine is now proved to have four protonation steps in the following basicity order: the sulfonamidate anion protonates at pH∈=∈11.3, followed by the protonation of the guanidine group at pH∈=∈6.8, whereas, in strong acidic solutions, two overlapping protonation processes occur involving the amidine and thiazole moieties. © 2011 Springer-Verlag.
Seres A.B.,University of Szeged |
Ducza E.,University of Szeged |
Bathori M.,University of Szeged |
Hunyadi A.,University of Szeged |
And 3 more authors.
Journal of Medicinal Food | Year: 2013
Numerous honeybee products are used in medicine, but the literature furnishes no information concerning the effects of the drone milk (DM), although drone brood, which is similar to DM, was reported to elicit a hormone-like strengthening effect. In certain countries, DM is traditionally used to treat infertility and to promote vitality in both men and women. The aim of this study was to determine the putative estrogen hormone-like effect of raw DM in rats and to identify the effective compounds. Uterotrophic assays revealed that DM increased the relative weight of the immature rat uterus. This effect was confirmed by reverse transcription polymerase chain-reaction and Western blot methods, in which the mRNA and protein expression of the estrogen-dependent peptide complement component C3 was determined. Column chromatography and uterotrophic assays were used to fractionate and check bioactivity, respectively. The active compound after the last fractionation was identified by the nuclear magnetic resonance and mass spectrometry techniques as E-dec-2-enedioic acid, which is very similar to the fatty acids with estrogenic activity that were previously isolated from royal jelly. These results lead us to suppose that E-dec-2-enedioic acid is responsible for the estrogen-like effect of DM. This appears to be the first report on the pharmacological effects of DM and E-dec-2-enedioic acid in mammals. © Copyright 2013, Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2013.
Seres A.B.,University of Szeged |
Ducza E.,University of Szeged |
Bathori M.,University of Szeged |
Hunyadi A.,University of Szeged |
And 5 more authors.
Journal of Ethnopharmacology | Year: 2014
Ethnopharmacological relevance Numerous honeybee (Apis mellifera) products have been used in traditional medicine to treat infertility and to increase vitality in both men and women. Drone milk (DM) is a relatively little-known honeybee product with a putative sexual hormone effect. The oestrogenic effect of a fraction of DM has recently been reported in rats. However, no information is available on the androgenic effects of DM. The purpose of the present study was to determine the androgen-like effect of DM in male rats and to identify effective compounds. Materials and methods A modified Hershberger assay was used to investigate the androgenic effect of crude DM, and the plasma level of testosterone was measured. The prostatic mRNA and protein expression of Spot14-like androgen-inducible protein (SLAP) were also examined with real-time PCR and Western blot techniques. GC-MS and NMR spectroscopic investigations were performed to identify the active components gained by bioactivity-guided fractionation. Results The crude DM increased the relative weights of the androgen-dependent organs and the plasma testosterone level in castrated rats and these actions were flutamide-sensitive. DM increased the tissue mRNA and protein level of SLAP, providing further evidence of its androgen-like character. After bioactivity-guided fractionation, two fatty acid esters, methyl palmitate (MP) and methyl oleate (MO), were identified as active compounds. MP alone showed an androgenic effect, whereas MO increased the weight of androgen-sensitive tissues and the plasma testosterone level only in combination. Conclusion The experimental data of DM and its active compounds (MO and MP) show androgenic activity confirming the traditional usage of DM. DM or MP or/and MO treatments may project a natural mode for the therapy of male infertility. © 2014 Elsevier Ireland Ltd.
PubMed | Compound Profiling Laboratory, Spectroscopic Research, Gedeon Richter Plc. and Institute of Ecology and Botany
Type: Journal Article | Journal: Journal of ethnopharmacology | Year: 2014
Oxybaphus nyctagineus (Michx.) Sweet has traditionally been used by several Native American tribes predominantly as a topical anti-inflammatory and analgesic agent.To evaluate the antioxidant, analgesic and anti-inflammatory activity of the extracts prepared from the aerial parts of Oxybaphus nyctagineus and to characterize the major chemical constituents of the bioactive extracts.Crude polar and apolar extracts (PCE and ACE) of the herb of Oxybaphus nyctagineus were prepared and tested in the models of the CFA-induced hyperalgesia in rat knee and carrageenan-induced paw edema in rat. To identify the active compounds, subfractions were prepared by column chromatography and subjected in vitro assays, such as antioxidant assays (DPPH, peroxynitrite (ONOO-) scavenging), and the LPS-induced IL-1 release test in human monocytes. Preparative HPLC was employed for the isolation of active substances, while phytochemical analysis was performed by mean of LC-MS/MS and NMR.The topically administered PCE and ACE of Oxybaphus nyctagineus demonstrated a significant analgesic and anti-inflammatory effect in the inflammation animal models. The subfraction A4 of ACE and the subfraction P5 of PCE considerably inhibited the LPS-induced IL-1 release in human monocytes, while the strongest activity was localized in the subfraction P5 in the antioxidant assays. The HPLC-MS/MS and NMR analysis revealed that 6-methoxyflavonol diglycosides, namely patuletin-3-O-robinobioside (1), 6-methoxykaempferol-3-O-robinobioside (2), spinacetin-3-O-robinobioside (3), and hydroxy-polyenoic fatty acids, namely corchorifatty acid B (4), 9-hydroxy-10E,12Z,15Z-octadecatrienoic acid (9-HOT acid) (5), and 9-hydroxy-10E,12Z-octadecadienoic acid (9-HOD acid) (6) were present in PCE, and in ACE as major compounds.The results of this study established a pharmacological evidence for the traditional use of Oxybaphus nyctagineus as an anti-inflammatory agent used topically, and provided data on its phytochemical composition for the first time.