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N-alkylamide profiling of Achillea ptarmica and Achillea millefolium extracts by liquid and gas chromatography–mass spectrometry

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Journal of Pharmaceutical Analysis 2017年第1期7卷 34-47页

作者： Lieselotte Veryser Lien Taevernier evelien wynendaele Yannick Verheust Ann Dumoulin Bart De Spiegeleer Drug Quality and Registration (DruQuaR) group Faculty of Pharmaceutical Sciences Ghent University Ottergemsesteenweg 460 B-9000 Ghent Belgium LIWET Department of Industrial Biological Sciences Ghent University Campus Kortrijk Graaf Karel de Goedelaan 5 B-8500 Kortrijk Belgium

Achillea millefolium and Achillea ptarmica are both plants belonging to the Asteracea family and are traditionally used for their medicinal properties. It has already been shown that some N-alkylamides(NAAs)are responsible for these pharmacological actions. Therefore, in the present study, the NAA content of the two plants was analytically characterised. Different extracts were prepared from the roots, the leaves, the stems and the flowers. The structures of NAAs have been assigned in ethanolic extracts of Achillea millefolium and Achillea ptarmica using high performance liquid chromatography – electrospray ionisation – mass spectrometry(HPLC–ESI–MS) and gas chromatography – electron impact – mass spectrometry(GC–EI–MS). Using both analytical techniques, the structures of 14 and 15 NAAs have been assigned in Achillea ptarmica and Achillea millefolium, respectively. Structures of two new NAAs, previously never observed in Achillea ptarmica,were assigned: deca-2E,6Z,8E-trienoic acid 2-methylbutylamide(homospilanthol) or a related isomeric compound and deca-2E,4E-dienoic acid N-methyl isobutylamide. The structure of homospilanthol or a related isomeric compound was also assigned in Achillea millefolium for the first time.

关键词： N-alkylamides Achillea millefolium Achillea ptarmica HPLC–ESI–MS GC–EI–MS

Analysis of iodinated quorum sensing peptides by LC–UV/ESI ion trap mass spectrometry

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Journal of Pharmaceutical Analysis 2018年第1期8卷 69-74页

作者： Yorick Janssens Frederick Verbeke Nathan Debunne evelien wynendaele Kathelijne Peremans Bart De Spiegeleer Drug Quality and Registration (DruQuaR) Group Faculty of Pharmaceutical Sciences Ghent University Department of Veterinary Medical Imaging and Small Animal Orthopaedics Faculty of Veterinary Medicine Ghent University

Five different quorum sensing peptides(QSP) were iodinated using different iodination techniques. These iodinated peptides were analyzed using a C18 reversed phase HPLC system, applying a linear gradient of water and acetonitrile containing 0.1%(m/v) formic acid as mobile phase. Electrospray ionization(ESI)ion trap mass spectrometry was used for the identification of the modified peptides, while semi-quantification was performed using total ion current(TIC) spectra. Non-iodinated peptides and mono-and diiodinated peptides(NIP, MIP and DIP respectively) were well separated and eluted in that order. Depending on the used iodination method, iodination yields varied from low(2%) to high(57%).

关键词： Peptide iodination LC–UV/MS Quorum sensing Bolton-Hunter

Analytical quality-by-design approach for sample treatment of BSA-containing solutions

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Journal of Pharmaceutical Analysis 2015年第1期5卷 27-32页

作者： Lien Taevernier evelien wynendaele Matthias D'Hondt Bart De Spiegeleer Drug Quality and Registration(DruQuaR)Group Faculty of Pharmaceutical SciencesGhent UniversityHarelbekestraat 72B-9000 GhentBelgium

The sample preparation of samples conlaining bovine serum albumin（BSA）,e.g..as used in transdermal Franz diffusion cell（FDC） solutions,was evaluated using an analytical qualily-by-design（QbD）*** precipitation of BSA by adding an equal volume of organic solvent,often successfully used with conventional HPLC-PDA,was found insufficiently robust when novel fused-core HPLC and/or UPLC-MS methods were *** this study,three factors（acetonitrile（%）.formic acid（%） and boiling time（min）） were included in the experimental design to determine an optimal and more suitable sample treatment of BSAcontaining FDC *** a QbD and Derringer desirability（D） approach,combining BSA loss,dilution factor and variability,we constructed an optimal working space with the edge of failure defined as D〈*** design space is modelled and is confirmed to have an ACN range of 83 ± 3% and FA content of 1 ±0.25%.

关键词： Bovine serum albumin(BSA)solutions Franz diffusion cell(FDC) Analytical quality-by-design(QbD) Sample preparation Design of experiment(DOE) Derringer desirability(D)

Quality evaluation of synthetic quorum sensing peptides used in R&D

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Journal of Pharmaceutical Analysis 2015年第3期5卷 169-181页

作者： Frederick Verbeke evelien wynendaele Sarah Braet Matthias D'Hondt Bart De Spiegeleer Drug Quality and Registration(DruQuaR) Group Faculty of Pharmaceutical SciencesGhent University

Peptides are becoming an important class of molecules in the pharmaceutical field. Closely related peptide-impurities in peptides are inherent to the synthesis approach and have demonstrated to potentially mask biomedical experimental results. Quorum sensing peptides are attracting high interest in R＆D and therefore a representative set of quorum sensing peptides, with a requested purity of at least 95.0%, was evaluated for their purity and nature of related impurities. In-house quality control （QC） revealed a large discrepancy between the purity levels as stated on the supplier＇s certificate of analysis and our QC results. By using our QC analysis flowchart, we demonstrated that only 44.0% of the peptides met the required purity. The main compound of one sample was even found to have a different structure compared to the desired peptide. We also found that the majority of the related impurities were lacking amino acid（s） in the desired peptide sequence. Relying on the certificates of analysis as provided by the supplier might have serious consequences for peptide research, and peptide-researchers should implement and maintain a thorough in-house QC.

关键词： Quorum sensing peptides Quality Impurity profiling

Derringer desirability and kinetic plot LC-column comparison approach for MS-compatible lipopeptide analysis

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Journal of Pharmaceutical Analysis 2014年第3期4卷 173-182页

作者： Matthias D’Hondt Frederick Verbeke Sofie Stalmans Bert Gevaert evelien wynendaele Bart De Spiegeleer Drug Quality and Registration (DruQuaR) Group Faculty of Pharmaceutical SciencesGhent University

Lipopeptides are currently re-emerging as an interesting subgroup in the peptide research field, having historical applications as antibacterial and antifungal agents and new potential applications as antiviral, antitumor, immune-modulating and cell-penetrating compounds. However, due to their specific structure, chromatographic analysis often requires special buffer systems or the use of trifluoroacetic acid, limiting mass spectrometry detection. Therefore, we used a traditional aqueous/acetonitrile based gradient system, containing 0.1% （m/v） formic acid, to separate four pharmaceutically relevant lipopeptides （polymyxin B1, caspofungin, daptomycin and gramicidin A1）, which were selected based upon hierarchical cluster analysis （HCA） and principal component analysis （PCA）.In total, the performance of four different C18 columns, including one UPLC column, were evaluated using two parallel approaches. First, a Derringer desirability function was used, whereby six single and multiple chromatographic response values were rescaled into one overall D-value per column. Using this approach, the YMC Pack Pro C18 column was ranked as the best column for general MS-compatible lipopeptide separation. Secondly, the kinetic plot approach was used to compare the different columns at different flow rate ranges. As the optimal kinetic column performance is obtained at its maximal pressure, the length elongation factor λ（Pmax/Pexp） was used to transform the obtained experimental data （retention times and peak capacities） and construct kinetic performance limit （KPL） curves, allowing a direct visual and unbiased comparison of the selected columns, whereby the YMC Triart C18 UPLC and ACE C18 columns performed as best. Finally, differences in column performance and the （dis）advantages of both approaches are discussed.

关键词： Lipopeptide Hierarchical cluster analysis (HCA) Principal component analysis (PCA) LC-MS Kinetic plot Derringer desirability function

Reversed-phase fused-core HPLC modeling of peptides

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Journal of Pharmaceutical Analysis 2013年第2期3卷 93-101页

作者： Matthias D'Hondt Bert Gevaert Sofie Stalmans Sylvia Van Dorpe evelien wynendaele Kathelijne Peremans Christian Burvenich Bart De Spiegeleer Drug Quality and Registration(DruQuaR) group Faculty of Pharmaceutical SciencesGhent UniversityHarelbekestraat 72B-9000 GhentBelgium Departments of Medical Imaging and Physiology Faculty of Veterinary MedicineGhent UniversitySalisburylaan 133B9820 MerelbekeBelgium

Different fused-core stationary phase chemistries（C18,Amide,Phenyl-hexyl and Peptide ES-C18） were used for the analysis of 21 structurally representative model *** addition,the effects of the mobile phase composition（ACN or MeOH as organic modifier;formic acid or acetic acid,as acidifying component） on the column selectivity,peak shape and overall chromatographic performance were *** RP-amide column,combined with a formic acid-acetonitrile based gradient system,performed as best.A peptide reversed-phase retention model is proposed,consisting of 5 variables：log SumAA,log Sv,clog P,log nHDon and log *** structure-retention relationship（QSRR） models were constructed for 16 different chromatographic *** accuracy of this peptide retention model was demonstrated by the comparison between predicted and experimentally obtained retention times,explaining on average 86% of the ***,using an external set of 5 validation peptides,the predictive power of the model was also *** peptide retention model includes the novel in-silico calculated amino acid descriptor,AA,which was calculated from log P,3D-MoRSE,RDF and WHIM descriptors.

关键词： Peptides Fused-core(core-shell core-enhanced poro-shell HALO s) stationary phases RP-HPLC peptide retention model In-silico amino acid descriptor

Differential leaf flooding resilience in Arabidopsis thaliana is controlled by ethylene signalingactivated and age-dependent phosphorylation of ORESARA1

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Plant Communications 2024年第6期5卷 73-88页

作者： Tom Rankenberg Hans van Veen Mastoureh Sedaghatmehr Che-Yang Liao Muthanna Biddanda Devaiah evelien AStouten Salma Balazadeh Rashmi Sasidharan Plant Stress Resilience Utrecht UniversityPadualaan 83584 CH Utrechtthe Netherlands Evolutionary Plant-Ecophysiology Groningen Institute for Evolutionary LIfe SciencesNijenborgh 79747 AG Groningenthe Netherlands Max Planck Institute of Molecular Plant Physiology Am Muhlenberg 114476 PotsdamGermany Experimental and Computational Plant Development Utrecht UniversityPadualaan 83584 CH Utrechtthe Netherlands Leiden University Leidenthe Netherlands

The phytohormone ethylene is a major regulator of plant adaptive responses to *** flooded plant tissues,ethylene quickly increases to high concentrations owing to its low solubility and diffusion rates in *** accumulation in submerged plant tissues makes it a reliable cue for triggering flood acclimation responses,including metabolic adjustments to cope with flood-induced ***,persistent ethylene accumulation also accelerates leaf ***-induced senescence hampers photosynthetic capacity and stress *** submerged Arabidopsis,senescence follows a strict age-dependent pattern starting with the older *** mechanisms underlying ethylene-mediated senescence have been uncovered,it is unclear how submerged plants avoid indiscriminate breakdown of leaves despite high systemic ethylene *** demonstrate that although submergence triggers leaf-age-independent activation of ethylene signaling viaEIN3 in Arabidopsis,senescence is initiated only inold ***3 stabilization also leads to overall transcript and protein accumulation of the senescence-promoting transcription factor ORESARA1(ORE1)in both old and young leaves during ***,leaf-age-dependent senescence can be explained by ORE1 protein activation via phosphorylation specifically in old leaves,independent of the previously identifiedage-dependentcontrol of ORE1 viami R164.A systematic analysis of the roles of the majorflooding stresscuesand signalingpathways shows that only the combination of ethylene and darkness is sufficientto mimic submergence-induced senescence involving ORE1 accumulation and ***,most of ten associated with flooding stress in plants,appears to have no role in these *** results reveal a mechanism by which plants regulate the speed and pattern of senescence during environmental stresses such as ***-dependent ORE1 activity ensures that older,expendable leaves are dismantled firs

关键词： ﬂooding abiotic stress hypoxia senescence ethylene

Androgens and estrogens in skeletal sexual dimorphism

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Asian Journal of Andrology 2014年第2期16卷 213-222,I0008页

作者： Michael Laurent Leen Antonio Mieke Sinnesael Vanessa Dubois evelien Gielen Frank Classens Dirk Vanderschueren Laboratory of Molecular Endocrinology Department of Cellular and Molecular Medicine Gerontology and Geriatrics Department of Clinical and Experimental Medicine KU Leuven Leuven Begum Geriatric Medicine University Hospitals Leuven Leuven Belgium Clinical and Experimental Endccrinology Department of Clinical and Experimental Medicine KU Leuven Leuven Belgium Endocrinology and Andrology Centre for Metabolic Bone Diseases Laboratory Medicine University Hospitals Leuven Leuven Belgium.

Bone is an endocrine tissue expressing androgen and estrogen receptors as well as steroid metabolizing enzymes. The bioactivity of circulating sex steroids is modulated by sex hormone-binding globulin and local conversion in bone tissue, for example, from testosterone （T） to estradiol （E2） by aromatase, or to dihydrotestosterone by 5（x-reductase enzymes. Our understanding of the structural basis for gender differences in bone strength has advanced considerably over recent years due to increasing use of （high resolution） peripheral computed tomography. These microarchitectural insights form the basis to understand sex steroid influences on male peak bone mass and turnover in cortical vs trabecular bone. Recent studies using Cre/LoxP technology have further refined our mechanistic insights from global knockout mice into the direct contributions of sex steroids and their respective nuclear receptors in osteoblasts, osteoclasts, osteocytes, and other cells to male osteoporosis. At the same time, these studies have reinforced the notion that androgen and estrogen deficiency have both direct and pleiotropic effects via interaction with, for example, insulin-like growth factor 1, inflammation, oxidative stress, central nervous system control of bone metabolism, adaptation to mechanical loading, etc., This review will summarize recent advances on these issues in the field of sex steroid actions in male bone homeostasis.

关键词： androgen receptor bone mineral density estradiol estrogen receptor male osteoblast osteoclast osteocyte osteoporosis sex hormone-binding globulin testosterone

Predominant mucosal expression of 5-HT_(4(+h)) receptor splice variants in pig stomach and colon

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World Journal of Gastroenterology 2013年第24期19卷 3747-3760页

作者： evelien KV Priem Joris H De Maeyer Mado Vandewoestyne Dieter Deforce Romain A Lefebvre Heymans Institute of Pharmacology Ghent UniversityB-9000 Ghent Belgium Shire-Movetis NV B-2300 Turnhout Belgium Laboratory for Pharmaceutical Biotechnology Ghent UniversityB-9000 Ghent Belgium

AIM: To investigate cellular 5-HT4(-h/+h) receptor distribution, particularly in the epithelial layer, by laser mi-crodissection and polymerase chain reaction (PCR) in porcine gastrointestinal (GI) tissues. METHODS: A stepwise approach was used to evaluate RNA quality and to study cell-specific 5-HT4 receptor mRNA expression in the porcine gastric fundus and colon descendens. After freezing, staining and laser microdissection and pressure catapulting (LMPC), RNA quality was evaluated by the Experion automated electrophoresis system. 5-HT4 receptor and glyceral-dehyde-3-phosphate dehydrogenase (GAPDH) expressions were examined by endpoint reverse transcription (RT)-PCR in mucosal and muscle-myenteric plexus (MMP) tissue fractions, in mucosal and MMP parts of hematoxylin and eosin (HE) stained tissue sections andin microdissected patches of the epithelial and circular smooth muscle cell layer in these sections. Pig gastric fundus tissue sections were also stained immunohisto-chemically (IHC) for enterochromaffin cells (EC cells; MAB352); these cells were isolated by LMPC and examined by endpoint RT-PCR. RESULTS: After HE staining, the epithelial and circular smooth muscle cell layer of pig colon descendens and the epithelial cell layer of gastric fundus were identified morphologically and isolated by LMPC. EC cells of pig gastric fundus were successfully stained by IHC and isolated by LMPC. Freezing, HE and IHC staining, and LMPC had no influence on RNA quality. 5-HT4 recep-tor and GAPDH mRNA expressions were detected in mucosa and MMP tissue fractions, and in mucosal and MMP parts of HE stained tissue sections of pig colon descendens and gastric fundus. In the mucosa tissue fractions of both GI regions, the expression of h-exon containing receptor [5-HT4(+h) receptor] mRNA was significantly higher (P<0.01) compared to 5-HT4(-h) re-ceptor expression, and a similar trend was obtained in the mucosal part of HE stained tissue sections. Large microdissected patches of the

关键词： 5-hydroxytryptamine 4 receptors Pig Gastric fundus Colon descendens Epithelium Smooth muscle Laser microdissection and pressure catapulting