@article{BechtSchollmayerMonakhovaetal.2021, author = {Becht, Alexander and Schollmayer, Curd and Monakhova, Yulia and Holzgrabe, Ulrike}, title = {Tracing the origin of paracetamol tablets by near-infrared, mid-infrared, and nuclear magnetic resonance spectroscopy using principal component analysis and linear discriminant analysis}, series = {Analytical and Bioanalytical Chemistry}, volume = {413}, journal = {Analytical and Bioanalytical Chemistry}, number = {11}, doi = {10.1007/s00216-021-03249-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265400}, pages = {3107-3118}, year = {2021}, abstract = {Most drugs are no longer produced in their own countries by the pharmaceutical companies, but by contract manufacturers or at manufacturing sites in countries that can produce more cheaply. This not only makes it difficult to trace them back but also leaves room for criminal organizations to fake them unnoticed. For these reasons, it is becoming increasingly difficult to determine the exact origin of drugs. The goal of this work was to investigate how exactly this is possible by using different spectroscopic methods like nuclear magnetic resonance and near- and mid-infrared spectroscopy in combination with multivariate data analysis. As an example, 56 out of 64 different paracetamol preparations, collected from 19 countries around the world, were chosen to investigate whether it is possible to determine the pharmaceutical company, manufacturing site, or country of origin. By means of suitable pre-processing of the spectra and the different information contained in each method, principal component analysis was able to evaluate manufacturing relationships between individual companies and to differentiate between production sites or formulations. Linear discriminant analysis showed different results depending on the spectral method and purpose. For all spectroscopic methods, it was found that the classification of the preparations to their manufacturer achieves better results than the classification to their pharmaceutical company. The best results were obtained with nuclear magnetic resonance and near-infrared data, with 94.6\%/99.6\% and 98.7/100\% of the spectra of the preparations correctly assigned to their pharmaceutical company or manufacturer.}, language = {en} } @article{VolpatoKaukMessereretal.2020, author = {Volpato, Daniela and Kauk, Michael and Messerer, Regina and Bermudez, Marcel and Wolber, Gerhard and Bock, Andreas and Hoffmann, Carsten and Holzgrabe, Ulrike}, title = {The Role of Orthosteric Building Blocks of Bitopic Ligands for Muscarinic M1 Receptors}, series = {ACS Omega}, volume = {5}, journal = {ACS Omega}, number = {49}, doi = {10.1021/acsomega.0c04220}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230548}, pages = {31706-31715}, year = {2020}, abstract = {The muscarinic M\(_1\) acetylcholine receptor is an important drug target for the treatment of various neurological disorders. Designing M\(_1\) receptor-selective drugs has proven challenging, mainly due to the high conservation of the acetylcholine binding site among muscarinic receptor subtypes. Therefore, less conserved and topographically distinct allosteric binding sites have been explored to increase M\(_1\) receptor selectivity. In this line, bitopic ligands, which target orthosteric and allosteric binding sites simultaneously, may provide a promising strategy. Here, we explore the allosteric, M1-selective BQCAd scaffold derived from BQCA as a starting point for the design, synthesis, and pharmacological evaluation of a series of novel bitopic ligands in which the orthosteric moieties and linker lengths are systematically varied. Since β-arrestin recruitment seems to be favorable to therapeutic implication, all the compounds were investigated by G protein and β-arrestin assays. Some bitopic ligands are partial to full agonists for G protein activation, some activate β-arrestin recruitment, and the degree of β-arrestin recruitment varies according to the respective modification. The allosteric BQCAd scaffold controls the positioning of the orthosteric ammonium group of all ligands, suggesting that this interaction is essential for stimulating G protein activation. However, β-arrestin recruitment is not affected. The novel set of bitopic ligands may constitute a toolbox to study the requirements of β-arrestin recruitment during ligand design for therapeutic usage.}, language = {en} } @article{SchmidtSkafGavriletal.2017, author = {Schmidt, Marianne and Skaf, Josef and Gavril, Georgiana and Polednik, Christine and Roller, Jeanette and Kessler, Michael and Holzgrabe, Ulrike}, title = {The influence of Osmunda regalis root extract on head and neck cancer cell proliferation, invasion and gene expression}, series = {BMC Complementary and Alternative Medicine}, volume = {17}, journal = {BMC Complementary and Alternative Medicine}, number = {518}, doi = {10.1186/s12906-017-2009-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158704}, year = {2017}, abstract = {Background: According to only a handful of historical sources, Osmunda regalis, the royal fern, has been used already in the middle age as an anti-cancer remedy. To examine this ancient cancer cure, an ethanolic extract of the roots was prepared and analysed in vitro on its effectiveness against head and neck cancer cell lines. Methods: Proliferation inhibition was measured with the MTT assay. Invasion inhibition was tested in a spheroid-based 3-D migration assay on different extracellular matrix surfaces. Corresponding changes in gene expression were analysed by qRT-PCR array. Induction of apoptosis was measured by fluorescence activated cell sorting (FACS) with the Annexin V binding method. The plant extract was analysed by preliminary phytochemical tests, liquid chromatography/mass spectroscopy (LC-MS) and thin layer chromatography (TLC). Anti-angiogenetic activity was determined by the tube formation assay. Results: O. regalis extract revealed a growth inhibiting effect on the head and neck carcinoma cell lines HLaC78 and FaDu. The toxic effect seems to be partially modulated by p-glycoprotein, as the MDR-1 expressing HLaC79-Tax cells were less sensitive. O. regalis extract inhibited the invasion of cell lines on diverse extracellular matrix substrates significantly. Especially the dispersion of the highly motile cell line HlaC78 on laminin was almost completely abrogated. Motility inhibition on laminin was accompanied by differential gene regulation of a variety of genes involved in cell adhesion and metastasis. Furthermore, O. regalis extract triggered apoptosis in HNSCC cell lines and inhibited tube formation of endothelial cells. Preliminary phytochemical analysis proved the presence of tannins, glycosides, steroids and saponins. Liquid chromatography/mass spectroscopy (LC-MS) revealed a major peak of an unknown substance with a molecular mass of 864.15 Da, comprising about 50\% of the total extract. Thin layer chromatography identified ferulic acid to be present in the extract. Conclusion: The presented results justify the use of royal fern extracts as an anti-cancer remedy in history and imply a further analysis of ingredients.}, language = {en} } @article{TriyasmonoSchollmayerSchmitzetal.2023, author = {Triyasmono, Liling and Schollmayer, Curd and Schmitz, Jens and Hovah, Emilie and Lombo, Cristian and Schmidt, Sebastian and Holzgrabe, Ulrike}, title = {Simultaneous determination of the saponification value, acid value, ester value, and iodine value in commercially available red fruit oil (Pandanus conoideus, Lam.) using \(^1\)H qNMR spectroscopy}, series = {Food Analytical Methods}, volume = {16}, journal = {Food Analytical Methods}, number = {1}, issn = {1936-9751}, doi = {10.1007/s12161-022-02401-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324728}, pages = {155-167}, year = {2023}, abstract = {Red fruit oil (RFO) can be extracted from fruits of Pandanus conoideus, Lam., an endogenous plant of Papua, Indonesia. It is a commonly used essential original traditional medicine. By applying a newly developed quantitative \(^1\)H NMR (qNMR) spectroscopy method for quality assessment, a simultaneous determination of the saponification value (SV), acid value (AV), ester value (EV), and iodine value (IV) in RFO was possible. Dimethyl sulfone (DMSO\(_2\)) was used as an internal standard. Optimization of NMR parameters, such as NMR pulse sequence, relaxation delay time, and receiver gain, finally established the \(^1\)H NMR-based quantification approach. Diagnostic signals of the internal standard at δ = 2.98 ppm, SV at δ = 2.37-2.20 ppm, AV at δ = 2.27-2.20 ppm, EV at δ = 2.37-2.27 ppm, and IV at δ = 5.37-5.27 ppm, respectively, were used for quantitative analysis. The method was validated concerning linearity (R\(^2\) = 0.999), precision (less than 0.83\%), and repeatability in the range 99.17-101.17\%. Furthermore, this method was successfully applied to crude RFO, crude RFO with palmitic and oleic acid addition, and nine commercial products. The qNMR results for the respective fat values are in accordance with the results of standard methods, as can be seen from the F- and t-test (< 1.65 and < 1.66, respectively). The fundamental advantages of qNMR, such as its rapidity and simplicity, make it a feasible and existing alternative to titration for the quality control of RFO.}, language = {en} } @article{GutierrezGiraldoDavilaCombarizaetal.2020, author = {Guti{\´e}rrez, Gustavo and Giraldo-D{\´a}vila, Deisy and Combariza, Marianny Y. and Holzgrabe, Ulrike and Tabares-Guevara, Jorge Humberto and Ram{\´i}rez-Pineda, Jos{\´e} Robinson and Ac{\´i}n, Sergio and Mu{\~n}oz, Diana Lorena and Montoya, Guillermo and Balcazar, Norman}, title = {Serjanic acid improves immunometabolic markers in a diet-induced obesity mouse model}, series = {Molecules}, volume = {25}, journal = {Molecules}, number = {7}, issn = {1420-3049}, doi = {10.3390/molecules25071486}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203253}, year = {2020}, abstract = {Plant extracts from Cecropia genus have been used by Latin-American traditional medicine to treat metabolic disorders and diabetes. Previous reports have shown that roots of Cecropia telenitida that contains serjanic acid as one of the most prominent and representative pentacyclic triterpenes. The study aimed to isolate serjanic acid and evaluate its effect in a prediabetic murine model by oral administration. A semi-pilot scale extraction was established and serjanic acid purification was followed using direct MALDI-TOF analysis. A diet induced obesity mouse model was used to determine the impact of serjanic acid over selected immunometabolic markers. Mice treated with serjanic acid showed decreased levels of cholesterol and triacylglycerols, increased blood insulin levels, decreased fasting blood glucose and improved glucose tolerance, and insulin sensitivity. At transcriptional level, the reduction of inflammation markers related to adipocyte differentiation is reported.}, language = {en} } @article{MasotaVoggOhlsenetal.2021, author = {Masota, Nelson E. and Vogg, Gerd and Ohlsen, Knut and Holzgrabe, Ulrike}, title = {Reproducibility challenges in the search for antibacterial compounds from nature}, series = {PLoS One}, volume = {16}, journal = {PLoS One}, number = {7}, doi = {10.1371/journal.pone.0255437}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260239}, year = {2021}, abstract = {Background Reproducibility of reported antibacterial activities of plant extracts has long remained questionable. Although plant-related factors should be well considered in serious pharmacognostic research, they are often not addressed in many research papers. Here we highlight the challenges in reproducing antibacterial activities of plant extracts. Methods Plants with reported antibacterial activities of interest were obtained from a literature review. Antibacterial activities against Escherichia coli and Klebsiella pneumoniae were tested using extracts' solutions in 10\% DMSO and acetone. Compositions of working solutions from both solvents were established using LC-MS analysis. Moreover, the availability of details likely to affect reproducibility was evaluated in articles which reported antibacterial activities of studied plants. Results Inhibition of bacterial growth at MIC of 256-1024 μg/mL was observed in only 15.4\% of identical plant species. These values were 4-16-fold higher than those reported earlier. Further, 18.2\% of related plant species had MICs of 128-256 μg/mL. Besides, 29.2\% and 95.8\% of the extracts were soluble to sparingly soluble in 10\% DMSO and acetone, respectively. Extracts' solutions in both solvents showed similar qualitative compositions, with differing quantities of corresponding phytochemicals. Details regarding seasons and growth state at collection were missing in 65\% and 95\% of evaluated articles, respectively. Likewise, solvents used to dissolve the extracts were lacking in 30\% of the articles, whereas 40\% of them used unidentified bacterial isolates. Conclusion Reproducibility of previously reported activities from plants' extracts is a multi-factorial aspect. Thus, collective approaches are necessary in addressing the highlighted challenges.}, language = {en} } @article{SeitzerKlapperMazigoetal.2021, author = {Seitzer, Moritz and Klapper, Sylvia and Mazigo, Humphrey D. and Holzgrabe, Ulrike and Mueller, Andreas}, title = {Quality and composition of Albendazole, Mebendazole and Praziquantel available in Burkina Faso, C{\^o}te d'Ivoire, Ghana and Tanzania}, series = {PLoS Neglected Tropical Diseases}, volume = {15}, journal = {PLoS Neglected Tropical Diseases}, number = {1}, doi = {10.1371/journal.pntd.0009038}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270434}, year = {2021}, abstract = {Background Even though the international combat against Neglected Tropical Diseases such as schistosomiasis or soil-transmitted helminthiases depends on reliable therapeutics, anthelminthic pharmacovigilance has been neglected on many national African drug markets. Therefore, quality and composition of Albendazole, Mebendazole and Praziquantel locally collected in Burkina Faso, C{\^o}te d'Ivoire, Ghana and Tanzania were analysed. Methods Samples of 88 different batches were obtained from randomly selected facilities. Sampling took place in Northwest Tanzania, Western Burkina Faso, Southeast C{\^o}te d'Ivoire and Southwest Ghana. Visual examination of both packaging and samples was performed according to the WHO 'Be Aware' tool. Products were then screened with the GPHF Minilab, consisting of tests of mass uniformity, disintegration times and thin-layer chromatography (TLC). Confirmatory tests were performed according to international pharmacopoeiae, applying assays for dissolution profiles and high-performance liquid chromatography (HPLC). Findings Despite minor irregularities, appearance of the products did not hint at falsified medicines. However, 19.6\% of the brands collected in Ghana and Tanzania were not officially licensed for sale. Mass uniformity was confirmed in 53 out of 58 brands of tablets. 41 out of 56 products passed disintegration times; 10 out of the 15 failing products did not disintegrate at all. Evaluating TLC results, only 4 out of 83 batches narrowly missed specification limits, 18 batches slightly exceeded them. Not more than 46.3\% (31 / 67) of the tablets assayed passed the respective pharmaceutical criteria for dissolution. HPLC findings confirmed TLC results despite shifted specification limits: 10 out of 83 tested batches contained less than 90\%, none exceeded 110\%. Conclusion In the four study countries, no falsified anthelminthic medicine was encountered. The active pharmaceutical ingredient was not found to either exceed or fall below specification limits. Galenic characteristics however, especially dissolution profiles, revealed great deficits.}, language = {en} } @article{MontoyaPelaezSierraAlzateetal.2013, author = {Montoya Pel{\´a}ez, Guillermo L. and Sierra, Jelver A. and Alzate, Fernando and Holzgrabe, Ulrike and Ramirez-Pineda, Jos{\´e} R.}, title = {Pentacyclic triterpenes from Cecropia telenitida with immunomodulatory activity on dendritic cells}, series = {Revista Brasileira de Farmacognosia - Brazilian Journal of Pharmacognosy}, volume = {23}, journal = {Revista Brasileira de Farmacognosia - Brazilian Journal of Pharmacognosy}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131851}, pages = {754-761}, year = {2013}, abstract = {Pentacyclic triterpenes are a large family of plant metabolites that exhibit a wide array of biological activities. The genus Cecropia, which encompasses many plant species, has been used as traditional medicine for the treatment of inflammatory diseases and is known to produce many active pentacyclic triterpenes. In this study we investigated the chemical composition of a pentacyclic triterpene fraction from the roots of Cecropia telenitida Cuatrec., Urticaceae. A novel compound, which we termed yarumic acid, and four known molecules (serjanic acid, spergulagenic acid A, 20-hydroxy-ursolic acid and goreishic acid I) were isolated and characterised. In a dendritic cell (DC)-based assay, we demonstrated that non-toxic doses of these pentacyclic triterpenes inhibited the secretion of at least one of the proinflammatory cytokines tested (IL-1 beta, IL-12p40, IL-12p70, TNF-alpha). Spergulagenic acid A also inhibited nitric oxide production in lipopolysaccharide-stimulated dendritic cell. Serjanic acid and spergulagenic acid A, which were the most potent abundant compounds in the pentacyclic triterpene fraction, showed the most activity in the dendritic cell-based assay. These results show that all pentacyclic triterpenes might contribute to the anti-inflammatory activities of C. telenitida. Moreover, yarumic acid as well as the four known pentacyclic triterpenes, can be exploited as potential immunomodulatory/anti-inflammatory agents.}, language = {en} } @article{HartungSeufertBergesetal.2012, author = {Hartung, Andreas and Seufert, Florian and Berges, Carsten and Gessner, Viktoria H. and Holzgrabe, Ulrike}, title = {One-Pot Ugi/Aza-Michael Synthesis of Highly Substituted 2,5-Diketopiperazines with Anti-Proliferative Properties}, series = {Molecules}, volume = {17}, journal = {Molecules}, number = {12}, doi = {10.3390/molecules171214685}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130423}, pages = {14685-14699}, year = {2012}, abstract = {The well-known Ugi reaction of aldehydes with amines, carboxylic acids and isocyanides leads to the formation of acyclic alpha-acylaminocarboxamides. Replacement of the carboxylic acid derivatives with beta-acyl substituted acrylic acids gives access to highly substituted 2,5-diketopiperazines in one single reaction-step without additives or complex reaction procedures. The obtained diketopiperazines show anti-proliferative effects on activated T cells and represent therefore potential candidates for targeting unwanted T cell-mediated immune responses.}, language = {en} } @article{MateraKaukCirilloetal.2023, author = {Matera, Carlo and Kauk, Michael and Cirillo, Davide and Maspero, Marco and Papotto, Claudio and Volpato, Daniela and Holzgrabe, Ulrike and De Amici, Marco and Hoffmann, Carsten and Dallanoce, Clelia}, title = {Novel Xanomeline-containing bitopic ligands of muscarinic acetylcholine receptors: design, synthesis and FRET investigation}, series = {Molecules}, volume = {28}, journal = {Molecules}, number = {5}, issn = {1420-3049}, doi = {10.3390/molecules28052407}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311249}, year = {2023}, abstract = {In the last few years, fluorescence resonance energy transfer (FRET) receptor sensors have contributed to the understanding of GPCR ligand binding and functional activation. FRET sensors based on muscarinic acetylcholine receptors (mAChRs) have been employed to study dual-steric ligands, allowing for the detection of different kinetics and distinguishing between partial, full, and super agonism. Herein, we report the synthesis of the two series of bitopic ligands, 12-Cn and 13-Cn, and their pharmacological investigation at the M\(_1\), M\(_2\), M\(_4\), and M\(_5\) FRET-based receptor sensors. The hybrids were prepared by merging the pharmacophoric moieties of the M\(_1\)/M\(_4\)-preferring orthosteric agonist Xanomeline 10 and the M\(_1\)-selective positive allosteric modulator 77-LH-28-1 (1-[3-(4-butyl-1-piperidinyl)propyl]-3,4-dihydro-2(1H)-quinolinone) 11. The two pharmacophores were connected through alkylene chains of different lengths (C3, C5, C7, and C9). Analyzing the FRET responses, the tertiary amine compounds 12-C5, 12-C7, and 12-C9 evidenced a selective activation of M\(_1\) mAChRs, while the methyl tetrahydropyridinium salts 13-C5, 13-C7, and 13-C9 showed a degree of selectivity for M\(_1\) and M\(_4\) mAChRs. Moreover, whereas hybrids 12-Cn showed an almost linear response at the M\(_1\) subtype, hybrids 13-Cn evidenced a bell-shaped activation response. This different activation pattern suggests that the positive charge anchoring the compound 13-Cn to the orthosteric site ensues a degree of receptor activation depending on the linker length, which induces a graded conformational interference with the binding pocket closure. These bitopic derivatives represent novel pharmacological tools for a better understanding of ligand-receptor interactions at a molecular level.}, language = {en} }