Kenia L. Vanzolini
Federal University of São Carlos
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Publication
Featured researches published by Kenia L. Vanzolini.
Journal of Chromatography A | 2011
Juliana Cristina Barreiro; Kenia L. Vanzolini; Quezia B. Cass
A two-dimensional liquid chromatography system coupled to ion-trap tandem mass spectrometer (2DLC-IT-MS/MS) was employed for the simultaneous quantification of pantoprazole and lansoprazole enantiomers fractions. A restricted access media of bovine serum albumin octyl column (RAM-BSA C(8)) was used in the first dimension for the exclusion of the humic substances, while a polysaccharide-based chiral column was used in the second dimension for the enantioseparation of both pharmaceuticals. The results described here show good selectivity, extraction efficiency, accuracy, and precision with detection limits of 0.200 and 0.150 μg L(-1) for the enatiomers of pantoprazole and lansoprazole respectively, while employing a small amount (1.0 mL) of native water sample per injection. This work reports an innovative assay for monitoring work, studies of biotic and abiotic enantioselective degradation and temporal changes of enantiomeric fractions.
Talanta | 2010
Juliana Cristina Barreiro; Kenia L. Vanzolini; Tânia Vieira Madureira; Maria Elizabeth Tiritan; Quezia B. Cass
This work reports the use of a two-dimensional liquid chromatography (2D-LC) system for quantification of the enantiomers of omeprazole in distinct native aqueous matrices. An octyl restricted-access media bovine serum albumin column (RAM-BSA C(8)) was used in the first dimension, while a polysaccharide-based chiral column was used in the second dimension with either ultraviolet (UV-vis) or ion-trap tandem mass spectrometry (IT-MS/MS) detection. An in-line configuration was employed to assess the exclusion capacity of the RAM-BSA columns to humic substances. The excluded macromolecules had a molecular mass in the order of 18 kDa. Good selectivity, extraction efficiency, accuracy, and precision were achieved employing a very small amount (500 microL or 1.00 mL) of native water sample per injection, with detection limits of 5.00 microg L(-1), using UV-vis, and 0.0250 microg L(-1), using IT-MS/MS. The total analysis time was only 35 min, with no time spent on sample preparation. The methods were successfully applied to analyze a series of waste and estuarine water samples. The enantiomers were detected in an estuarine water sample collected from the Douro River estuary (Portugal) and in an influent sample from the wastewater treatment plant (WWTP) of São Carlos (Brazil). As far as we are concerned, this is the first report of the occurrence of (+)-omeprazole and (-)-omeprazole in native aqueous matrices.
Journal of Medicinal Chemistry | 2013
Kenia L. Vanzolini; Lucas Campos Curcino Vieira; Arlene G. Corrêa; Carmen Lúcia Cardoso; Quezia B. Cass
The use of immobilized capillary enzyme reactors (ICERs) for online ligand screening has been adopted as a new technique for high-throughput screening (HTS). In this work, the selected target was the enzyme acetylcholinesterase (AChE), and the AChE-ICERs produced were used in a liquid chromatograph-tandem ion-trap mass spectrometer. The activity and kinetic parameters were evaluated by monitoring the cholines precursor ion (M + H)(+)m/z 104.0 and its ion fragment (C2H3OH) - (M + H)(+)m/z 60.0. The assay method was validated using the reference AChE inhibitors tacrine and galanthamine. Two new ligands, out of a library of 17 coumarin derivatives, were identified, and the half-maximal inhibitory concentration (IC50), inhibition constant (K(i)), and the inhibition mechanism were determined. A coumarin derivative with IC50 similar to tacrine was highlighted.
Journal of Pharmaceutical and Biomedical Analysis | 2014
Marcela Cristina de Moraes; Kenia L. Vanzolini; Carmen Lúcia Cardoso; Quezia B. Cass
The diversity of small molecules available to produce truly innovative drugs associated with the wealth of known biological targets calls for key strategies in protein ligand screening. This review encompasses the recently developed bioaffinity-based strategies. A critical view of the use of zonal, frontal, and nonlinear chromatography with immobilized proteins is given. The association of these elution modes with the ligand fishing method, which uses nanomagnetics particles, is also addressed. A series of applications and how these new screening strategies can be used to determine the function, affinity, and activity parameters of proteins is discussed.
Bioorganic & Medicinal Chemistry | 2016
Marili Villa Nova Rodrigues; Alexandre F. Barbosa; Júlia F. da Silva; Deborah A. dos Santos; Kenia L. Vanzolini; Marcela Cristina de Moraes; Arlene G. Corrêa; Quezia B. Cass
A novel potent xanthine oxidase inhibitor, 3-nitrobenzoyl 9-deazaguanine (LSPN451), was selected from a series of 10 synthetic derivatives. The enzymatic assays were carried out using an on-flow bidimensional liquid chromatography (2D LC) system, which allowed the screening¸ the measurement of the kinetic inhibition constant and the characterization of the inhibition mode. This compound showed a non-competitive inhibition mechanism with more affinity for the enzyme-substrate complex than for the free enzyme, and inhibition constant of 55.1±9.80 nM, about thirty times more potent than allopurinol. Further details of synthesis and enzymatic studies are presented herein.
Journal of the Brazilian Chemical Society | 2014
Diego P. Sangi; Julia L. Monteiro; Kenia L. Vanzolini; Quezia B. Cass; Márcio W. Paixão; Arlene G. Corrêa
Polarized ketene dithioketals have been recognized as useful building blocks in many synthetic operations. In this work, a transition-metal-free annulations of 1,1-bis(thiomethyl)-2-nitroethylene with hydroxylalkylamines or alkyldiamines have been reported. This methodology provides a directed approach to N-heterocycles, e.g., imidazolidines, oxazolidines and benzoxazoles under microwave conditions. These compounds were evaluated as acetylcholinesterase inhibitors by using an enzyme immobilized capillary reactor-tandem mass spectrometry.
Journal of the Brazilian Chemical Society | 2016
Fernando Cidade Torres; Guilherme Gonçalves; Kenia L. Vanzolini; Aloir Antonio Merlo; Bruna Gauer; Maribete Holzschuh; Saulo Fernandes Andrade; Maristela Piedade; Solange Cristina Garcia; Ivone Carvalho; Gilsane Lino von Poser; Daniel Fábio Kawano; Vera Lucia Eifler-Lima; Quezia B. Cass
Coumarins are a large class of compounds that display a range of interesting biological properties, being considered privileged structures because of the ability of their 2H-chromen-2-one nuclei to bind to multiple pharmacological targets. We hypothesized that the linkage of a second pharmacophore nucleus to the 2H-chromen-2-one core, the 1,2,3-triazole moiety, would entail more selective and pharmacologically active coumarins. Therefore, we describe the synthesis of fourteen 4-methylcoumarins/1,4-substituted 1,2,3-triazole conjugates, which were predicted by in silico methods to inhibit acetylcholinesterase (AChE) and proved to be moderate in vitro inhibitors of this enzyme. Molecular docking simulations suggest that the most active of these compounds has a putative binding mode similar to donepezil, both occupying the peripheral anionic site of AChE, which is associated with the secondary noncholinergic functions of the enzyme. This highlights the potential of this series for further optimization in the search of new coumarins for the treatment of Alzheimers disease.
RSC Advances | 2015
Marili Villa Nova Rodrigues; Rodrigo S. Corrêa; Kenia L. Vanzolini; Diógenes Santiago Santos; Alzir A. Batista; Quezia B. Cass
Xanthine oxidase (XO) is an enzyme in the purine salvage pathway that catalyzes the oxidation of hypoxanthine to xanthine with subsequent production of uric acid from the xanthine oxidation, and it has been considered an important target of newly developed inhibitors. Based on the advantages of using immobilized capillary enzyme reactors (ICERs) in a 2D LC system as a tool for screening new enzymatic ligands, this work validated an XO-ICER using allopurinol as a positive control. Despite the complex interaction between XO and allopurinol due its tight binding nature, it was possible to recognize the inhibitory kinetics parameters through Morrisons equation. The tight binding nature of inhibition was established by varying the IC50 values according to the substrate concentration. The kinetic inhibitory profile of allopurinol was used to validate the XO-ICER. Then, the XO-ICER was used to screen specific ruthenium derivatives. The selected compound, 4CBALO, an allopurinol ruthenium derivative, exhibited 100% inhibition at 200 μM compared to 86% inhibition from allopurinol at the same concentration. The inhibitory effect on the immobilized XO was reversible after the elution of the compound, with immediate recovery of the ICER activity. Additionally, 4CBALO behaved as a selective and competitive tight binder of xanthine oxidase with a true Ki value of 0.29 μM, which was obtained from the Morrison equation. This report describes the first on-flow characterization of tight binders of xanthine oxidase.
Journal of Pharmaceutical and Biomedical Analysis | 2017
Fernando G. de Almeida; Kenia L. Vanzolini; Quezia B. Cass
Graphical abstract Figure. No Caption available. HighlightsA strategy to find new ACE inhibitory peptides using ACE‐MB and LC–MS/MS.ACE was purified, identified and immobilized onto modified surface magnetic beads.ACE‐MB showed specificity towards two substrates and Michaelian kinetic behavior.A new tool arises as an efficient way to fish encrypted peptides as ACE‐ligands. ABSTRACT Angiotensin converting enzyme (ACE) presents an important role in blood pressure regulation, since that converts angiotensin I to the vasoconstrictor angiotensin II. Some commercially available ACE inhibitors are captopril, lisinopril and enalapril; due to their side effects, naturally occurring inhibitors have been prospected. In order to endorse this research field we have developed a new tool for ACE ligand screening. To this end, ACE was extracted from bovine lung, purified and chemically immobilized in modified ferrite magnetic beads (ACE‐MBs). The ACE‐MBs have shown a Michaelian kinetic behavior towards hippuryl‐histidyl‐leucine. Moreover, as proof of concept, the ACE‐MBs was inhibited by lisinopril with a half maximal inhibitory concentration (IC50) of 10 nM. At the fishing assay, ACE‐MBs were able not only to fish out the reference inhibitor, but also one peptide from a pool of tryptic digested BSA. In conclusion, ACE‐MBs emerge as new straightforward tool for ACE kinetics determination, inhibition and binder screening.
Toxicon | 2018
Kenia L. Vanzolini; Stuart Ainsworth; Ben Bruyneel; Volker Herzig; Mitchell G.L. Seraus; Govert W. Somsen; Nicholas R. Casewell; Quezia B. Cass; Jeroen Kool
ABSTRACT Acetylcholinesterase (AChE) from Electrophorus electricus (eel) was immobilized on the surface of amino‐modified paramagnetic beads to serve as a model for the development, validation and application of a new affinity‐based ligand‐fishing assay for the discovery of bioactive peptides from complex protein mixtures such as venoms. Nano liquid chromatography‐mass spectrometry (nanoLC‐MS) was used for the analysis of trapped peptides. Using enzyme‐functionalized beads, the ligand‐fishing assay was evaluated and optimized using a peptide reference mixture composed of one acetylcholinesterase binder (fasciculin‐II) and five non‐binders (mambalgin‐1, angiotensin‐II, bradykinin, cardiotoxin and &agr;‐bungarotoxin). As proof of concept, snake venom samples spiked with fasciculin‐II demonstrated assay selectivity and sensitivity, fishing the peptide binder from complex venom solutions at concentrations as low as 1.0 &mgr;g/mL. As negative controls for method validation, venoms of four different snake species, not known to harbor AChE binding peptides, were screened and no AChE binders were detected. The applicability of the ligand fishing assay was subsequently demonstrated with venom from the black mamba, Jamesons mamba and western green mamba (Dendroaspis spp.), which have previously been reported to contain the AChE binding fasciculins. Unknown peptides (i.e. not fasciculins) with affinity to AChE were recovered from all mamba venoms tested. Tryptic digestion followed by nano‐LC‐MS analysis of the material recovered from black mamba venom identified the peptide with highest AChE‐binding affinity as dendrotoxin‐I, a pre‐synaptic neurotoxin previously not known to interact with AChE. Co‐incubation of AChE with various dendrotoxins in vitro revealed reduced inactivation of AChE activity over time, thus demonstrating that these toxins stabilize AChE. HighlightsAn affinity‐based assay was developed for the screening of AChE peptide binders in animal venoms.The assay was validated and applied to snake venoms.AChE binders were retrieved and analyzed by nanoLC‐MS.Dendrotoxin‐I from black mamba venom was revealed to bind to AChE allosterically and to stabilize AChE activity in vitro.