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Abdirahman Elmi Fatouma Mohamed Abdoul-Latif Rosella Spina Franois Dupire Stphanie Philippot Champy Marie-France Hugues Jacobs Dominique Laurain-Mattar 《Molecules (Basel, Switzerland)》2021,26(10)
For the first time, the study of the antioxidant activity, the characterization of the phytoconstituants, and the evaluation of in vitro and in vivo toxicity of A. djiboutiensis leave and latex are performed. The antioxidant activity of both latex (ADL) and the methanolic extract of leaves (ADM) is determined using 1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) scavenging radical methods and ferric reducing/antioxidant power (FRAP) assay. The phytochemical study of latex is done using Liquid Chromatography-Mass Spectrometry (LC-MS/MS) and a molecular networking-based approach. The evaluation of in vivo toxicity is performed on mice by oral gavage with a suspension of ADL. Our results show that weak antioxidant activity of ADL and ADM in opposition to their high polyphenol, 83.01 mg and 46.4 mg expressed in gallic acid equivalent (GAE)/g of dry weight (DW), respectively, and flavonoid contents 13.12 mg and 4.25 mg expressed in quercetin equivalent (QE)/g dry weight (DW), respectively. Using the Global Natural Products Social Molecular Networking (GNPS) website, nine (9) anthraquinones derivatives, ten (10) chromones derivatives, two (2) flavonols/ chromones isomers are annotated in the molecular network. The treated mice do not display abnormalities in their general physical appearance and biochemistry parameters, compared to the controls. Only glucose and calcium levels are slightly higher in male treated mice compared to the vehicles. 相似文献
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This paper investigates the role of CDS volatility in providing information concerning the credit quality of a company. In Castellano and D’Ecclesia (J. Financ. Decis. Mak. 2:27, 2011) a first analysis of how CDS quotes respond to rating announcements is provided and it showed that market participants do not rely much on Rating Agencies, especially during periods characterized by very high volatility, i.e. during a financial crisis. Here, a more accurate analysis of the CDS’s ability to provide timely information on the creditworthiness of reference entities is performed, estimating the volatility of CDS quotes by using Exponential GARCH(1,1) models. The event study methodology is applied to a sample of CDS quotes for US and European markets, over the period 2004–2009. Results provide an accurate understanding of market behavior in the presence of news released by Rating Agencies. Overall, market participants seem to provide timely reactions around the event date and we show that the key element of signaling is represented by the changing volatility in CDS quotes, before and after the rating event. 相似文献
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A column‐switching HPLC‐MS/MS method for mucopolysaccharidosis type I analysis in a multiplex assay for the simultaneous newborn screening of six lysosomal storage disorders
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Antonina Gucciardi Elisa Legnini Iole Maria Di Gangi Carlo Corbetta Rosella Tomanin Maurizio Scarpa Giuseppe Giordano 《Biomedical chromatography : BMC》2014,28(8):1131-1139
Lysosomal storage disorders comprise a group of rare genetic diseases in which a deficit of specific hydrolases leads to the storage of undegraded substrates in lysosomes. Impaired enzyme activities can be assessed by MS/MS quantification of the reaction products obtained after incubation with specific substrates. In this study, a column‐switching HPLC‐MS/MS method for multiplex screening in dried blood spot of the lysosomal enzymes activities was developed. Mucopolysaccharidosis type I, Fabry, Gaucher, Krabbe, Niemann–Pick A/B and Pompe diseases were simultaneously assayed. Dried blood spots were incubated with substrates and internal standards; thereafter, supernatants were collected with minor manipulations. Samples were injected, trapped into an online perfusion column and, by a six‐port valve, switched online through the C18 analytical column to perform separation of metabolites followed by MS/MS analysis. A total of 1136 de‐identified newborn screening samples were analyzed to determine references for enzymes activity values. As positive controls, we analyzed dried blood spots from three patients with Pompe, one with Fabry, one with Krabbe disease and two with MPS I, and in all cases the enzyme activities were below the cutoff values measured for newborns, except for an MPS I patient after successful hematopoietic stem cell transplantation. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Rosella Ferretti Bruno GallinellaFrancesco La Torre Leo ZanittiLuciana Turchetto Antonina MoscaRoberto Cirilli 《Journal of chromatography. A》2009,1216(28):5385-5390
High-performance liquid chromatography (HPLC) enantioseparation of terazosin (TER) was accomplished on the immobilised-type Chiralpak IC chiral stationary phase (CSP) under both polar organic and reversed-phase modes. A simple analytical method was validated using a mixture of methanol–water–DEA 95:5:0.1 (v/v/v) as a mobile phase. Under reversed-phase conditions good linearities were obtained over the concentration range 8.76–26.28 μg mL−1 for both enantiomers. The limits of detection and quantification were 10 and 30 ng mL−1, respectively. The intra- and inter-day assay precision was less than 1.66% (RSD%). The optimised conditions also allowed to resolve chiral and achiral impurities from the enantiomers of TER. The proposed HPLC method supports pharmacological studies on the biological effects of the both forms of TER and analytical investigations of potential drug formulations based on a single enantiomer. At the semipreparative scale, 5.3 mg of racemic sample were resolved with elution times less than 12 min using a mobile phase consisting of methanol–DEA 100:0.1 (v/v) and both enantiomers were isolated with a purity of ≥99% enantiomeric excess (ee). The absolute configuration of TER enantiomers was assigned by comparison of the measured specific rotations with those reported in the literature. 相似文献
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Mustazza C Borioni A Sestili I Sbraccia M Rodomonte A Ferretti R Del Giudice MR 《Chemical & pharmaceutical bulletin》2006,54(5):611-622
Some spiro[piperidine-4,2'(1'H)-quinazolin]-4'(3'H)-ones 3 and spiro[piperidine-4,5'(6'H)-[1,2,4]triazolo[1,5-c]quinazolines] 4 were synthesized and evaluated as ligands of the nociceptin receptor. The examined compounds showed partial agonistic activity, except compounds 3, 4n that proved to be pure antagonists. 相似文献
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Alcaro S Bolasco A Cirilli R Ferretti R Fioravanti R Ortuso F 《Journal of chemical information and modeling》2012,52(3):649-654
A computer-aided design of novel asymmetric pyrazoles with improved enantioselective properties was performed by docking experiments starting from a model of Chiralcel OJ chiral in the stationary phase. Synthesis and HPLC experiments confirmed the theoretical prediction and led to a detailed investigation of the enantioselective recognition process. For the first time, looking at the time spent by each enantiomer in contact with the CSP during long molecular dynamic simulations, the experimental analytical trend has been reproduced. 相似文献
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Marta Colombo Rosella Ferretti Leo Zanitti Roberto Cirilli 《Journal of separation science》2020,43(13):2589-2593
Ramosetron is an enantiopure active pharmaceutical ingredient marketed in Japan since 1996 and later in a few Southeast Asian countries predominantly as an antiemetic for patients receiving chemotherapy. In this study, a simple and rapid high‐performance liquid chromoatography method for the separation of ramosetron and its related enantiomeric impurity by using hydrophilic interaction liquid chromatography mode is presented. Chiral resolution was performed on an analytical column (100 mm × 4.6 mm id) packed with 3 μm particles of cellulose‐based Chiralpak IC‐3 chiral stationary phase. Using a mobile phase containing acetonitrile–water–diethylamine (100:10:0.1, v/v/v) and setting the column temperature at 35°C, the resolution value was 7.35. At a flow rate of 1 mL/min, the enantioseparation was completed within 5 min. The proposed method was partially validated and it has proven to be sensitive with limit of detection and limit of quantitation of the (S)‐enantiomer impurity of 44.5 and 133.6 ng/mL. 相似文献