A series of four thiosemicarbazones from 6-nitropiperonal along with the corresponding copper complexes were synthesized. The biophysical characteristics of the complexes were investigated by the binding to DNA and human serum albumin. The binding to DNA is moderate; the binding constants run from (0.49–7.50) × 104 M− 1. In relation to HSA, the complexes interact strongly with binding constants on the order of 105 M− 1. The complexes also display antioxidant behavior as determined by the ability to scavenge diphenylpicrylhydrazyl (dpph) and nitric oxide radicals. The antimicrobial profiles of the compounds, tested against a panel of microbes including five of the ESKAPE pathogens (Staphylococcus aureus, MRSA, Escherichia coli, Klebsiella pneumoniae, MDR, Acinetobacter baumannii, Pseudomonas aeruginosa) and two yeasts (Candida albicans and Cryptococcus neoformans var. grubii), are also described. The compounds contain a core moiety that is similar to oxolinic acid, a quinolone antibiotic that targets DNA gyrase and topoisomerase (IV). The binding interaction between the complexes and these important antibacterial targets were studied by computational methods, chiefly docking studies. The calculated dissociation constants for the interaction with DNA gyrase B (from Staphylococcus aureus) range from 4.32 to 24.65 μM; the binding was much stronger to topoisomerase IV, with dissociation constants ranging from 0.37 to 1.27 μM.
The MS analysis was carried out using Advion Expression® CMS.
Aarajana Shrestha, HyeJin Oh, Mi Jin Kim, Nirmala Tilija Pun, Til Bahadur Thapa Magar, Ganesh Bist, Hongseok Choi, Pil-Hoon Park, Eung-Seok Lee
As a continuous effort to discover new potential anti-inflammatory agents, we systematically designed and synthesized sixty-one 2-benzylidene-1-indanone derivatives with structural modification of chalcone, and evaluated their inhibitory activity on LPS-stimulated ROS production in RAW 264.7 macrophages. Systematic structure-activity relationship study revealed that hydroxyl group in C-5, C-6, or C-7 position of indanone moiety, and ortho-, meta-, or para-fluorine, trifluoromethyl, trifluoromethoxy, and bromine functionalities in phenyl ring are important for inhibition of ROS production in LPS-stimulated RAW 264.7 macrophages. Among all the tested compounds, 6-hydroxy-2-(2-(trifluoromethoxy) benzylidene)-2,3-dihydro-1H-inden-1-one (compound 44) showed the strongest inhibitory activity of ROS production. Further studies on the mode of action revealed that compound 44 potently suppressed LPS-stimulated ROS production via modulation of NADPH oxidase. The findings of this work could be useful to design 2-benzylidene-indanone based lead compounds as novel anti-inflammatory agents.
The MS analysis was carried out using Advion Expression® CMS.
Christian Hoppmann, Allison Wong, Bing Yang, Shuwei Li, Tony Hunter, Kevan M. Shokat, Lei Wang
Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active phosphotyrosine-containing proteins by genetically encoding a stable phosphotyrosine analog that is convertible to native phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination.
The MS analysis was carried out using Advion Expression® CMS ESI.
Marie Monestier, Dimitrios Latousakis, Andrew Bell, Sandra Tribal, Louise E. Tailford, Ian J. Colquhoun, Gwenaelle Le Gall, Hai Yu, Xi Chen, Martin Rejzek, Simone Dedola, Robert A. Field, Nathalie Juge
Naturally occurring 2,7-anhydro-alpha-N-acetylneuraminic acid (2,7-anhydro-Neu5Ac) is a transglycosylation product of bacterial intramolecular trans-sialidases (IT-sialidases). A facile one-pot two-enzyme approach has been established for the synthesis of 2,7-anhydro-sialic acid derivatives including those containing different sialic acid forms such as Neu5Ac and N-glycolylneuraminic acid (Neu5Gc). The approach is based on the use of Ruminoccocus gnavus IT-sialidase for the release of 2,7-anhydro-sialic acid from glycoproteins, and the conversion of free sialic acid by a sialic acid aldolase. This synthetic method, which is based on a membrane-enclosed enzymatic synthesis, can be performed on a preparative scale. Using fetuin as a substrate, high-yield and cost-effective production of 2,7-anhydro-Neu5Ac was obtained to high-purity. This method was also applied to the synthesis of 2,7-anhydro-Neu5Gc. The membrane-enclosed multienzyme (MEME) strategy reported here provides an efficient approach to produce a variety of sialic acid derivatives.
The MS analysis was carried out using Advion Expression® CMS ESI.
Harrison C. Daly, Gonzalo Sampedro, Corentin Bon, Dan Wu, Ghazi Cahill, Roman A. Cahill, Donal F. O’Shea
The use of near-infrared fluorescence for in vivo research and intraoperative clinical imaging is rapidly expanding, with new applications being proposed and developed. While imaging hardware and software have significantly progressed in recent times, the molecular fluorescent agents remain a limiting factor. In this report, the design, synthesis, photophysical characterization and bio-medical imaging assessment of two new NIR-fluorophores based on the BF2-azadipyrromethene fluorophore class are described. Inclusion of dimethylamino substituents on these BF2-azadipyrromethene probes results in very large bathochromic shifts with photophysical measurements showing absorption and emission maxima between 757 and 818 nm within the desired NIR spectra region. Testing of the probes shows that they are suitable for fluorescence imaging with both research and clinical instrumentation. Preclinical imaging assessment shows their suitability as fluorescent markers (tattoos) of lesions for intraoperative identification and lymphatic mapping in ex vivo human colonic tissue. These new clinical wavelength-compatible fluorophores may contribute towards the on-going expansion of medical uses for NIR-fluorescence.
The LC/MS analysis was carried out using Advion Expression® CMS.
UV-cured transparent acrylic pressure sensitive adhesives (PSAs) composed of semi-interpenetrating networks were prepared using the menthyl acrylate (MnA) and tetrahydro-geraniol acrylate (TGA) synthesized from menthol and tetrahydro geraniol, respectively. This study investigated the adhesion performance and environmental reliability of the resulting acrylic PSAs by changing the mole ratio for MnA and TGA while fixing the mole ratio for 2-hydroxyehtyl acrylate (2-HEA) in the PSAs. Also, the optical properties of the acrylic PSAs for optically clear adhesive applications were examined by UV–Vis spectroscopy, color-difference meter, and haze meter. All acrylic PSAs exhibited high transparency (>92%) and stable weatherability under reliability testing (85/85 test), regardless of the various comonomer compositions. The resulting acrylic PSAs showed proper adhesion performance to be allowed to use as optically clear adhesive; 180° peel strength of 1.6–4.0 kgf/25 mm, probe tack of 0.25–0.43 kgf, and shear holding power of 0.10–0.17 mm.
The MS analysis was carried out using Advion Expression® CMS.
Martin Doert, Stephanie Krüger, Gertrud E. Morlock, Lothar W. Kroh
Ternary mixtures of lecithins, vitamin C and vitamin E are powerful antioxidants for the stabilization of polyunsaturated (n-3 fatty acid) oils. In this study, the chemistry of the antioxidant synergistic effect was investigated in ethyl linoleate (EL) containing α-tocopherol (α-Toc) or in linoleate rich vegetable oils at 110 °C using mixtures of phosphatidylethanolamine (PE) and either l-ascorbic acid (AA) or l-dehydroascorbic acid (DHA). The highest stabilization effects in EL were similar in both systems and were found in the molar mixtures of PE and AA or DHA. The thermal formation of reaction products between PE and AA (PE–AA) or DHA (PE–DHA) were investigated by HPTLC/ESI-MS. When α-tocopherylquinone (α-TQ) was used instead of α-Toc, nearly the same antioxidant effect was observed in the EL system. It was shown that molar mixtures of PE and AA, or PE and DHA, can regenerate α-TQ to α-Toc at elevated temperatures. PE–AA was synthesized and tested as antioxidants in EL containing α-Toc and in vegetable oils at room temperature. An improved stabilization was observed with the synthesized derivative compared to the physical mixture of the compounds, which demonstrated that PE–AA is a potential new antioxidant. A mechanism for the synergistic action between PE, AA and α-Toc through an acid-catalysed regeneration of α-TQ is suggested. PE–AA is an active apolar antioxidant, which is involved in the reduction of α-TQ.
The MS analysis was carried out using Advion Expression® CMS TLC and ESI.
Rajesh H. Vekariya, Kinjal D. Patel, Dhanji P. Rajani, Smita D. Rajani, Hitesh D. Patel
A convenient, one-pot, multi-component protocol for the preparation of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinecarbothioamide derivatives has been achieved. Here, firstly we have reported the synthesis of 3-acetyl-2H-chromen-2-one using starch sulfuric acid and cellulose sulfuric acid as biodegradable catalysts. Subsequently, we also carried out the reaction of isothiocynates, hydrazine hydrate and 3-acetyl-2H-chromen-2-one in the presence of catalytic amount of glacial acetic acid in refluxing ethanol to afford corresponding 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinecarbothioamide derivatives in high to excellent yields. All synthesized compounds were screened for antimicrobial activity. All compounds were found to show good to excellent activity against Escherichia coli MTCC 443.
Using the tetrahydro-geraniol acrylate (TGA) synthesized from biomass tetrahydro-geraniol, UV-cured transparent acrylic pressure sensitive adhesives (PSAs) composed of semi-interpenetrating networks were successfully fabricated. The utility for optically clear adhesive on adhesion performances according to various concentrations of TGA in the acrylic PSAs were investigated. After characterizing the photo-polymerized PSA syrups, the optical properties for the acrylic PSA films were examined using UV–vis spectroscopy, a color-difference meter, and a haze meter. The acrylic PSAs exhibited high transparency and stable weather-ability under reliability testing (85/85 test). With increasing TGA concentration in the acrylic PSAs, adhesion properties such as the 180° peel strength, shear holding power, and probe tack had decreased.
The LC/MS analysis was carried out using Advion Expression® CMS.
Additi Roy Chowdhury, Biswajit Gopal Roy, Saibal Jana, Thomas Weyhermuller, Priyata Banerjee
Novel colorimetric hydrazine-functionalized Schiff base chemoreceptor [N1N3bis(perfluorobenzylidene)isophthalahydrazide] NBPBIH has been prepared for selective detection of F−. In this receptor more NH and CN units are incorporated for better colorimetric responses as compared to systems having lesser number of such units. NBPBIH turns from colorless to dark yellow on exposure to F−. The detection event is well supported by UV–vis, fluorescence, 1H and 19F-NMR like spectrophotometric and cyclic voltammetric studies in DMSO because of enhanced fluorescence responses, higher Stokes shift value and for its less toxic nature compared to other solvents. Quenching of fluorescence is explained with photoinduced electron transfer mechanism (PET). The binding constant of NBPBIH with F− is around 0.84 × 105 M−1 and limit of detection of F− is found 1.42 × 10−5 M. Our concern is also to address fluorosis: an issue related to global health problem, affecting millions of common people. It is noteworthy that the existing diagnostic and treatment options are of huge expenses. As an artefact, chemoreceptor assisted simple prototype for detecting excessive fluoride in sample solution has been designed and developed which has potential and good prospect to be applied as a low cost affordable diagnostic kit for fluorosis in largely affected countries like China, India and several others.
The MS analysis was carried out using Advion Expression® CMS ESI.
N units are incorporated for better colorimetric responses as compared to systems having lesser number of such units. NBPBIH turns from colorless to dark yellow on exposure to F−. The detection event is well supported by UV–vis, fluorescence, 1H and 19F-NMR like spectrophotometric and cyclic voltammetric studies in DMSO because of enhanced fluorescence responses, higher Stokes shift value and for its less toxic nature compared to other solvents. Quenching of fluorescence is explained with photoinduced electron transfer mechanism (PET). The binding constant of NBPBIH with F− is around 0.84 × 105 M−1 and limit of detection of F− is found 1.42 × 10−5 M. Our concern is also to address fluorosis: an issue related to global health problem, affecting millions of common people. It is noteworthy that the existing diagnostic and treatment options are of huge expenses. As an artefact, chemoreceptor assisted simple prototype for detecting excessive fluoride in sample solution has been designed and developed which has potential and good prospect to be applied as a low cost affordable diagnostic kit for fluorosis in largely affected countries like China, India and several others.