Search results for "Electrospray ionization"
showing 10 items of 275 documents
Bistacrine derivatives as new potent antimalarials
2016
Linking two tacrine molecules results in a tremendous increase of activity against Plasmodia in comparison to the monomer. This finding prompted the synthesis of a library of monomeric and dimeric tacrine derivatives in order to derive structure-activity relationships. The most active compounds towards chloroquine sensitive Plasmodium strain 3D7 and chloroquine resistant strain Dd2 show IC50 values in the nanomolar range of concentration, low cytotoxicity and target the cysteine protease falcipain-2, which is essential for parasite growth.
Chemical characterization of a variety of cold-pressed gourmet oils available on the Brazilian market
2018
Different specialty extra virgin oils, produced by cold-pressing fruits/nuts (olive, pequi, palm, avocado, coconut, macadamia and Brazil nut) and seeds (grapeseed and canola), and retailed in the Brazilian region of Minas Gerais, were chemically characterized. Specifically, for each type of oil, the fatty acid composition was elucidated by GC-FID, the contents of selected polyphenols and squalene were determined respectively by UHPLC-MS and UHPLC-PDA, whereas minerals were explored by means of ICP-MS. Olive oil was confirmed to have the highest MUFA content due to a valuable level of oleic acid, while oils from grapeseed, Brazil nut and canola were marked by nutritionally important PUFA lev…
Influence of pitanga leaf extracts on lipid and protein oxidation of pork burger during shelf-life
2018
Abstract The effect of pitanga leaf extracts, as source of natural antioxidants, on physicochemical properties as well as lipid and protein oxidation of pork burgers during storage at 2 ± 1 °C, packed under modified atmosphere, was assessed. Formerly, the in vitro antioxidant and antimicrobial activities as well as the phenolic profile of pitanga leaf extracts were also studied. Thereafter, five samples were prepared, including control (without antioxidants), commercial synthetic antioxidant (BHT at 200 mg/kg) and three concentrations of pitanga leaf extracts: PLL (at 250 mg/kg), PLM (at 500 mg/kg) and PLH (at 1000 mg/kg). The predominant phenolic compounds identified in pitanga leaf extrac…
Determinants for Tight and Selective Binding of a Medicinal Dicarbene Gold(I) Complex to a Telomeric DNA G-Quadruplex: a Joint ESI MS and XRD Investi…
2016
International audience; The dicarbene gold(I) complex [Au(9-methylcaffein-8-ylidene)(2)]BF4 is an exceptional organometallic compound of profound interest as a prospective anticancer agent. This gold(I) complex was previously reported to be highly cytotoxic toward various cancer cell lines invitro and behaves as a selective G-quadruplex stabilizer. Interactions of the gold complex with various telomeric DNA models have been analyzed by a combined ESI MS and X-ray diffraction (XRD) approach. ESI MS measurements confirmed formation of stable adducts between the intact gold(I) complex and Tel 23 DNA sequence. The crystal structure of the adduct formed between [Au(9-methylcaffein-8-ylidene)(2)]…
Evaluation of Alternaria mycotoxins in strawberries: quantification and storage condition
2016
Alternariol (AOH), alternariol methyl ether (AME) and tentoxin (TEN) are Alternaria mycotoxins produced by the most common post-harvest pathogens of fruits. The production of these metabolites depends on several environmental factors, mainly temperature, water activity, pH and the technological treatments that have been applied to the product. In this study, the occurrence of AOH, AME and TEN was evaluated in strawberries samples stored at different temperatures ranges (at 22 ± 2 or 6 ± 2°C) and different periods (up to 1 month) simulating the current practice of consumer's storage conditions. Sample extraction was performed using a liquid-liquid extraction method prior to LC-MS/MS analysis…
Colletotrin: a sesquiterpene lactone from the endophytic fungus Colletotrichum gloeosporioides associated with Trichilia monadelpha
2017
Abstract A new sesquiterpene lactone, namely colletotrin (1), together with two known fungal metabolites (2, 3), was obtained from a rice culture of Colletotrichum gloeosporioides, an endophytic fungus isolated from the stem bark of Cameroonian medicinal plant Trichilia monadelpha (Meliaceae). The structure of the new compound was established on the basis of extensive NMR analysis (1H, 13C, heteronuclear single-quantum coherence and heteronuclear multiple-bond correlation) completed by high-resolution electrospray ionization mass spectroscopy results and by comparison of these data with those of related compounds described in the literature. Their cytotoxic and antibacterial activities agai…
Oxidation-Induced Increase In Photoreactivity of Bovine Retinal Lipid Extract
2017
Open access original paper Source : 10th EPR Workshop on Applications of EPR in Biology and Medicine, 2016 in Krakow, POLAND.; International audience; The mammalian retina contains a high level of polyunsaturated fatty acids, including docosahexaenoic acid (22:6) (DHA), which are highly susceptible to oxidation. It has been shown that one of the products of DHA oxidation-carboxyethylpyrrole (CEP), generated in situ, causes modifications of retinal proteins and induces inflammation response in the outer retina. These contributing factors may play a role in the development of age-related macular degeneration (AMD). It is also possible that some of the lipid oxidation products are photoreactiv…
Native Electrospray-based Metabolomics Enables the Detection of Metal-binding Compounds
2019
AbstractMetals are essential for the molecular machineries of life, and microbes have evolved a variety of small molecules to acquire, compete for, and utilize metals. Systematic methods for the discovery of metal-small molecule complexes from biological samples are limited. Here we describe a two-step native electrospray ionization mass spectrometry method, in which double-barrel post-column metal-infusion and pH adjustment is combined with ion identity molecular networking, a rule-based informatics workflow. This method can be used to identify metal-binding compounds in complex samples based on defined mass (m/z) offsets of ion features with the same chromatographic profiles. As this nati…
LC‐ESI / HRMS analysis of glucosinolates, oxylipins and phenols in Italian rocket salad ( Diplotaxis erucoides subsp. erucoides (L.) DC .) and evalua…
2021
BACKGROUND This study investigated the chemical profile and biological activity of Diplotaxis erucoides subsp. erucoides (L.) DC. (Brassicaceae) collected in Sicily (Italy). RESULTS Liquid chromatography coupled with electrospray ionization and high-resolution mass spectrometry (LC-ESI/HRMS) analysis of the ethanol extract revealed the presence of 42 compounds - glucosinolates, hydroxycinnamic acids, flavonoids, and oxylipins. The extract was tested for its antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), ferric reducing ability power (FRAP), and β-carotene bleaching tests. Promising protection from lipid peroxida…
Ag11(SG)7 : A New Cluster Identified by Mass Spectrometry and Optical Spectroscopy
2014
We report a one-step and high yield synthesis of a red-luminescent silver cluster with the molecular formula, Ag11(SG)7 (SG: glutathionate) via reduction of silver ions by sodium borohydride in the presence of the tripeptide, glutathione (GSH). The as-prepared cluster shows prominent absorption features at 485 and 625 nm in its UV-vis absorption spectrum. Aging of the as-prepared cluster solution led to the disappearance of the 625 nm peak, followed by broadening of the 485 nm peak to give three maxima at ?487, 437, and 393 nm in its absorption spectrum. These peaks remain unchanged even after polyacrylamide gel electrophoresis (PAGE), where a single band was observed confirming high purity…