1H and 13C NMR spectral assignments of some phenothiazine derivatives

1H and 13C NMR data for six pheno‐thiazine derivatives are reported. Spectral assignments were made on the basis of two‐dimensional homonuclear 1H,1H and heteronuclear 1H,13C correlation techniques (COSY, COSY‐LR, HETCOR, COLOC) and 13C,1H coupling constant measurements. Copyright © 1994 John Wiley & Sons Limite

Stability and reactivity of γ-ΜPTMS silane in some commercial primer and adhesive formulations

Objectives: To evaluate the stability and reactivity of γ-methacryloxypropyl trimethoxysilane (MPTMS) in commercially available primers and adhesives. Methods: Four representative primer formulations [Calibra Silane Coupling Agent/Dentsply (CLB), G-Multi Primer/GC (GMP), Kerr Silane Primer/Kerr (KSP), Monobond Plus/Ivoclar Vivadent (MBP)] and a universal adhesive [Scotchbond Universal/3M ESPE (SBU)] containing MPTMS were analyzed spectroscopically. For the stability study, the silanol content was evaluated in bulk solutions as received (reference-RE) and after aging (AG, 48 °C/1 month) by 1H, 13C, 31P NMR and in fresh films by transmission FTIR analysis (TIR, films applied on Ge windows after solvent evaporation). The reactivity, as expressed by the siloxane formation capacity of the RE products, was evaluated by micro-multiple internal reflectance FTIR analysis (MIR, films applied on Ge crystals) after drying and ethanol rinsing (t0) and following 1 (t1) and 24 h (t24) storage (air/37 °C). Results: NMR and TIR showed ∼60% MPTMS silanol groups in RE-CLB, with the other (∼40%) groups being methylated or ethoxylated. In AG-CLB, the silanol peaks further decreased, while ethoxylation and siloxane derivatization increased. In all other products and aging conditions no silanols were traced and formation of small- and large-size MPTMS derivatives was evident. Apart from the 10-MDP molecule, phosphorous impurities were identified in all RE specimens (2–5%), which after AG reached a maximum value of 15% (MBP). MIR analysis showed siloxane formation in all products, regardless the presence of free silanols (t1), which further increased at t24 especially in CLB, GMP and MBP. Significance: MPTMS silanols are very sensitive to mild thermal aging. Incorporation of MPTMS in the same vials with adhesive and conventional methacrylate monomers, results in derivatization with no detectable silanols, even in fresh materials. The condensates formed may induce additional siloxane formation due to residual activity, which greatly varies among the materials tested. These may have a detrimental effect on MPTMS silanol chemisorption and bonding capacity. © 2018 The Academy of Dental Material

(E)-(1-(4-ethoxycarbonylphenyl)-5-(3,4-dimethoxyphe nyl)-3-(3,4-dimethoxystyryl)-2-pyrazoline: Synthesis, characterization, dna-interaction, and evaluation of activity against drug-resistant cell lines

(E)-1-(4-Ethoxycarbonylphenyl)-5-(3,4-dimethoxyphenyl)-3-(3,4-dimethoxystyryl)-2-pyrazoline was synthesized via the cyclization reaction between the monocarbonyl curcuminoid (2E,6E)-2,6-bis(3,4-dimethoxybenzylidene)acetone and ethyl hydrazinobenzoate in high yield and purity (>95% by High-performance liquid chromatography (HPLC)). The compound has been fully characterized by1H,13C NMR, FTIR, UV-Vis and HRMS and its activity was evaluated in terms of its potential interaction with DNA as well as its cytotoxicity against resistant and non-resistant tumor cells. Both DNA thermal denaturation and DNA viscosity measurements revealed that a significant intercalation binding takes place upon treatment of the DNA with the synthesized pyrazoline, causing an increase in melting temperature by 3.53 ± 0.11 °C and considerable DNA lengthening and viscosity increase. However, neither re-sensitisation of Doxorubicin (DO X)-resistant breast cancer and multidrug resistance (MDR) reversal nor synergistic activity with DOX by potentially increasing the DOX cell killing ability was observed. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Fusarium graminearum 1H NMR metabolomics

Raw 1H NMR spectra of Fusarium graminearum hyphae can be found at the website of the pesticide metabolomics group (PMG) of the Agricultural University of Athens at the address: http://www.aua.gr/pesticide-metabolomicsgroup/Resources/Fusarium_graminearum_NMR_spectra.html, accession number PMG-01–17. The data set support the research article “Implication of Fusarium graminearum Primary Metabolism in its Resistance to Benzimidazole Fungicides as revealed by 1H NMR Metabolomics” [1]

Palladium(II) and platinum(II) complexes of derivatives of 2-(4′-aminophenyl)benzothiazole as potential anticancer agents

The synthesis, structural characterization and in vitro biological evaluation of two 2-(4′-aminophenyl)benzothiazole based ligands and their corresponding Pd(II) and Pt(II) complexes is reported. Their design was based on the selective anticancer action of phenylbenzothiazole in conjunction with the cytotoxicity of the metallic center, aiming at targeted and synergistic effectiveness of the complexes as anticancer agents. All compounds were fully characterized with IR, NMR and MS analysis and their binding to CT-DNA was investigated by UV–Vis spectroscopy, fluorescence, circular dichroism, viscometry, and thermal denaturation. The data indicate that both ligands interact with CT-DNA via a combined mode of action involving both groove binding and non-classical intercalation, while in the case of the complexes covalent bond formation takes place as well. The in vitro cytotoxicity and cell uptake studies in human breast carcinoma cell line (MCF-7 and MDA-MB-231) as well as in healthy human skin fibroblasts (DSF) show uptake of the intact complexes by cancer cells and increased activity against cancer cell lines. © 2016 Elsevier B.V

Oleuropein, an anti-oxidant polyphenol constituent of olive promotes α-Secretase cleavage of the amyloid precursor protein (AβPP)

Over the past decade, intense focus has been dedicated on investigating processes involved in the proteolysis of amyloid precursor protein (AβPP) and β-amyloid (Aβ) peptide metabolism, as possible targets for Alzheimer's disease (AD) therapy. To this goal, considerable research has been targeted on potential therapeutic use of compounds promoting non-amyloidogenic processing of AβPP. One of these compounds, oleuropein, a polyphenol constituent of extra virgin olive oil exhibiting a wide range of pharmacological properties, was shown to interact non-covalently with Aβ, an interaction that might be related to a potential protective role of oleuropein against Aβ aggregation. In the present study, it was demonstrated that oleuropein treatment of HEK293 cells stably transfected with the isoform 695 of human AβPP (APP695) leads to markedly elevated levels of sAPPα and to significant reduction of Aβ oligomers. These effects were associated with increased activity of matrix metalloproteinase 9 (MMP-9), whereas no significant alterations in the expression of secretases TACE, ADAM-10 or BACE-1 were observed. Similar results were obtained using the human neuroblastoma cell line SK-N-SH. The experimental data reveal an anti-amyloidogenic effect of oleuropein and suggest a possible protective role for oleuropein against AD, extending the spectrum of beneficial properties of this naturally occurring polyphenol. © 2012 Springer Science+Business Media New York

Inducing the formation of a colloidal albumin carrier of curcumin

The administration and delivery of pharmaceuticals faces a variety of well-known obstacles that result in limited biocompatibility and bioavailability. Efforts to improve these properties have often employed serum albumin, primarily due to its inherent biocompatibility and its ability to enhance the circulation times of pharmaceuticals. In this work, we have adapted a nanoparticle-formulation protocol, to produce a protein carrier of curcumin with bovine serum albumin. This was achieved by using a near-equimolar protein:curcumin ratio instead of the abundance of curcumin that would be normally used in a nanoparticle formulation. Photometric and quantitative analysis of this carrier showed an increased curcumin content in the produced aqueous solutions following the homogenization of bovine serum albumin (water) and curcumin (dichloromethane) phases. Albumin fluorescence studies indicated curcumin association near a tryptophan residue, without excluding the possibility of additional sites. Circular dichroism provided strong evidence of this association through the induced circular dichroism effect and showed that the secondary structure of bovine serum albumin was effectively maintained. Overall, this work presented a new means of facilitating the association of increased levels of curcumin with bovine serum albumin, which could potentially be used to generate additional non-covalent albumin carriers for pharmaceutical compounds. © 2022 The Author

Detection of interactions of the β-amyloid peptide with small molecules employing transferred NOEs

The interaction of pineal hormone melatonin, the histological dye thioflavin T, and the olive tree polyphenol oleuropein, with the 28 amino acid residue N-terminal fragment of the β-amyloid peptide (β-AP) of Alzheimer's disease, [β-AP(1-28)], was detected in solution through the observationof transferredNOEs (trNOEs) in1Dand2DNOEspectroscopy (NOESY) experiments. The trNOE method is applied for the first time in the detection of interactions of soluble β-AP(1-28) with small molecules and may provide a means of screening for the identification of possible inhibitors of the formation of neurotoxic β-AP assemblies. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd

Solution structure of Ser14Gly-humanin, a potent rescue factor against neuronal cell death in Alzheimer's disease

The NMR solution study of Ser14Gly-humanin (S14G-HN), a 1000-fold more potent derivative of humanin (HN), is reported. HN is 24-residue peptide that selectively suppresses neuronal cell death caused by Alzheimer's disease (AD)-specific insults and offers hope for the development of a cure against AD. In aqueous solution the NMR data show that S14G-HN is a flexible peptide with turn-like structures in its conformational ensemble distributed over an extensive part of its sequence from Pro3 to Glu15. In the more lipophilic environment of 30% TFE, an α-helical structure spanning residues Phe6 to Thr13 is identified. Comparison of these findings to the NMR structure of the parent HN and to existing structure-function relationship literature data outlines the important for activity structural features for this class of neuroprotective peptides, and brings forth flexibility as an important characteristic that may facilitate interactions with functional counterparts of the neuroprotection pathway. © 2006 Elsevier Inc. All rights reserved

High-resolution NMR spectroscopy of the β-amyloid(1-28) fibril typical for Alzheimer's disease

Unlabeled samples of the β-amyloid peptide(1-28) fibrils typical of Alzheimer's disease could be used to obtain well-resolved one- and two-dimensional 1H NMR spectra (see picture). The technique applied was high-resolution magic-angle spinning on a 600 MHz NMR spectrometer. The results are in agreement with a parallel, in-register arrangement of the β-amyloid peptide in the fibril