Search results for: Marcella Niccoli

Items from 1 to 20 out of 20 results

article

Host–guest inclusion complex of quercetin and hydroxypropyl-β-cyclodextrin

Federica D’Aria, Carla Serri, Marcella Niccoli, Laura Mayol, more

Journal of Thermal Analysis and Calorimetry > 2017 > 130 > 1 > 451-456

Quercetin (QCT), a flavonoid derived from many fruits and vegetables, is endowed with manifold biological properties, such as the ability to elicit a strong inhibitory effect on the growth of several tumor cell lines. Unfortunately, the pharmacological application of QCT is severely restricted by its inherent hydrophobicity and consequent low in vivo bioavailability. The therapeutic potential of QCT...

article

Cyclodextrin–protein interaction as inhibiting factor against aggregation

Marcella Niccoli, Rosario Oliva, Giuseppina Castronuovo

Journal of Thermal Analysis and Calorimetry > 2017 > 127 > 2 > 1491-1499

With the aim of better understanding how cyclodextrins can inhibit protein aggregation, a calorimetric study is reported concerning the determination of the thermodynamic properties characterizing the interaction process between natural or modified cyclodextrins and two model proteins: lysozyme and ovalbumin. The study will examine how the interaction depends on the dimensions of cyclodextrins, on...

article

The conformational stability of ovalbumin and lysozyme in the aqueous solutions of various cosolvents

Marcella Niccoli, Giuseppina Castronuovo

Journal of Thermal Analysis and Calorimetry > 2016 > 123 > 3 > 2149-2156

A thermodynamic method is reported to monitor the conformational stability of lysozyme and ovalbumin in the presence of various cosolvents. Heats of dilution of the proteins in concentrated aqueous solutions of urea, ethanol or glucose have been determined at 298.15 K by flow microcalorimetry. The pairwise enthalpic interaction coefficients of the proteins in the different solvent media are derived:...

article

Experimental evidence of stable water nanostructures in extremely dilute solutions, at standard pressure and temperature

Vittorio Elia, Giovanni Ausanio, Francesco Gentile, Roberto Germano, more

Homeopathy > 2014 > 103 > 1 > 44-50

This paper presents the results of several experimental methods (FT-IR spectroscopy, UV–vis spectroscopy, fluorescence microscopy (FM), Atomic Force Microscopy (AFM)) evidencing structural changes induced in extremely diluted solutions (EDS), which are prepared by an iterated process of centesimal (1:100) dilution and succussion (shaking). The iteration is repeated until an extremely high dilution...

article

On the mechanism of ion transport through lipid membranes mediated by PEGylated cyclic oligosaccharides (CyPLOS): An ESR study

Elena Busi, Giuseppe Vitiello, Marcella Niccoli, Riccardo Basosi, more

BBA - Biomembranes > 2013 > 1828 > 9 > 2074-2082

The mechanism underlying the ionophoric activity of CyPLOS (cyclic phosphate-linked oligosaccharide, 2), a carbohydrate-based synthetic ion transporter decorated with four tetraethylene glycol (TEG) chains, has been investigated by an integrated electron spin resonance (ESR) approach. The mode of interaction of the ionophore with lipid bilayers has been studied by quantitatively analyzing the perturbations...

article

Thermodynamics of inclusion complexes of natural and modified cyclodextrins with acetylsalicylic acid and ibuprofen in aqueous solution at 298K

Giuseppina Castronuovo, Marcella Niccoli

Thermochimica Acta > 2013 > 557 > Complete > 44-49

Thermodynamic parameters for the association of natural and substituted α-, β-, and γ-cyclodextrins with acetylsalicylic acid, salicylic acid and ibuprofen have been determined by isothermal titration calorimetry. Analysis of the data shows that complexes form, all having 1:1 stoichiometry. The shape-matching between the host and guest is the factor determining the values of the thermodynamic quantities...

article

Calorimetric, conductometric and density measurements of iteratively filtered water using 450, 200, 100 and 25 nm Millipore filters

Vittorio Elia, Nadia Marchettini, Elena Napoli, Marcella Niccoli

Journal of Thermal Analysis and Calorimetry > 2013 > 114 > 2 > 927-936

This study presents some experimental results on the variation of the physico-chemical properties of pure MilliQ water, when subjected to a procedure of iterated filtration through Millipore filters with porosity ranging from 450 to 25 nm. The parameters measured were: calorimetry, electrical conductivity, density, and pH. Release of chemical impurities can be ruled out due to the nature of the materials...

article

A calorimetric study of the interactions in the aqueous solutions of lysozyme in the presence of denaturing cosolvents

Giuseppina Castronuovo, Marcella Niccoli

Thermochimica Acta > 2012 > 543 > Complete > 254-259

A thermodynamic method is reported to monitor the chemical denaturation of lysozyme. Heats of dilution of the protein in concentrated aqueous solutions of urea or ethanol have been determined at 298.15 K by flow microcalorimetry. The pairwise enthalpic interaction coefficients of the protein in the different solvent media are derived. These parameters allow to gain information about the influence...

article

Solvent effects on the complexation of 1-alkanols by parent and modified cyclodextrins. Calorimetric studies at 298 K

Giuseppina Castronuovo, Marcella Niccoli

Journal of Thermal Analysis and Calorimetry > 2011 > 103 > 2 > 641-646

The formation of complexes of parent and alkylated cyclodextrins (CDs) with 1-heptanol and 1-octanol has been studied calorimetrically at 298 K in water and in concentrated aqueous solutions of urea. The forces involved in the association process are discussed in the light of the signs and values of the thermodynamic parameters obtained: association enthalpy, binding constant, Gibbs free energy, and...

article

The influence of cosolvents on hydrophilic and hydrophobic interactions. Calorimetric studies of parent and alkylated cyclomaltooligosaccharides in concentrated aqueous solutions of ethanol or urea

Giuseppina Castronuovo, Marcella Niccoli

Carbohydrate Research > 2008 > 343 > 16 > 2771-2775

Heats of dilution in water and in aqueous 7molkg ⁻¹ urea and 3molkg ⁻¹ ethanol of binary solutions containing cyclomaltohexaose, cyclomaltoheptaose, cyclomaltooctaose, 2-hydroxypropyl-cyclomaltohexaose (HPαCD), 2-hydroxypropyl-cyclomaltoheptaose (HPβCD), methyl-cyclomaltohexaose (MeαCD), methyl-cyclomaltoheptaose (MeβCD) and 2-hydroxypropyl-cyclomaltooctaose (HPγCD) have been determined...

article

Complexation forces in aqueous solution. Calorimetric studies of the association of 2-hydroxypropyl-β-cyclodextrin with monocarboxylic acids or cycloalkanols

Giuseppina Castronuovo, Marcella Niccoli, Luigi Varriale

Tetrahedron > 2007 > 63 > 30 > 7047-7052

The formation of complexes between 2-hydroxypropyl-β-cyclodextrin and monocarboxylic acids or cycloalkanols has been studied calorimetrically at 298K in phosphate buffer, pH 11.3. The forces involved in the association process are discussed in the light of the signs and values of the thermodynamic parameters obtained: association enthalpy, binding constant, Gibbs free energy, and entropy.From this...

article

The cavity elongation effect. Calorimetric studies of the complexes of long-chain carboxylic acids with methyl-α-cyclodextrin in aqueous solutions

Giuseppina Castronuovo, Marcella Niccoli

Journal of Inclusion Phenomena and Macrocyclic Chemistry > 2007 > 58 > 3-4 > 289-294

The formation of complexes between methyl-α-cyclodextrin (MαCD) and monocarboxylic acids from C₅ to C₁₂ or cycloalkanols has been studied calorimetrically at 298 K in aqueous phosphate buffer, pH 11.3. The forces involved in the association process are discussed according to the signs and values of the thermodynamic parameters obtained: association enthalpy, constant, Gibbs energy and entropy. Methyl-α-cyclodextrin...

article

Thermodynamics of inclusion complexes of natural and modified cyclodextrins with propranolol in aqueous solution at 298K

Giuseppina Castronuovo, Marcella Niccoli

Bioorganic & Medicinal Chemistry > 2006 > 14 > 11 > 3883-3887

The association constant, standard Gibbs energy, enthalpy and entropy for formation of inclusion complexes of propranolol, a β-blocker, with various natural and modified cyclodextrins have been determined by calorimetry at 298K. Both natural and methyl-modified α-cyclodextrins do not form complexes, while β- and γ-cyclodextrins do. Complexing ability of 2-hydroxypropyl-β-cyclodextrin depends on the...

article

Calorimetric studies of aromatic model compounds in aqueous solutions at 298K

Giuseppina Castronuovo, Marcella Niccoli

Thermochimica Acta > 2005 > 433 > 1-2 > 51-55

Pairwise enthalpic interaction coefficients of the virial expansion of the excess enthalpies were determined at 298K by measuring the enthalpies of dilution in aqueous solution of binary aqueous solutions containing 4-hydroxyphenylacetic acid, 2-phenylethanol, 3-phenylpropanol, 3-phenylpropionic acid, l-tyrosine and l-phenylalanine. Coefficients obtained are compared with those already reported in...

article

Complexation of natural and methylated β-cyclodextrins with long-chain Carboxylic acids in aqueous solutions. Calorimetric studies at 298 K

Giuseppina Castronuovo, Marcella Niccoli

Journal of Inclusion Phenomena and Macrocyclic Chemistry > 2005 > 53 > 1-2 > 69-76

The formation of complexes between β-cyclodextrin or methyl-β-cyclodextrin and monocarboxylic acids from C₅ to C₁₂ has been studied calorimetrically at 298 K in aqueous buffer phosphate, pH 11.3. When a complex forms, calorimetry enables the calculation of both the enthalpy and the association constant, from which the Gibbs free energy and the entropy of the process can be obtained. The forces involved...

article

Complexation of natural and methylated β-cyclodextrins with long-chain Carboxylic acids in aqueous solutions. Calorimetric studies at 298 K

Giuseppina Castronuovo, Marcella Niccoli

Journal of Inclusion Phenomena and Macrocyclic Chemistry > 2005 > 53 > 1 > 69-76

The formation of complexes between β-cyclodextrin or methyl-β-cyclodextrin and monocarboxylic acids from C5 to C12 has been studied calorimetrically at 298 K in aqueous buffer phosphate, pH 11.3. When a complex forms, calorimetry enables the calculation of both the enthalpy and the association constant, from which the Gibbs free energy and the entropy of the process can be obtained. The forces involved...

article

Study of the Effects of Cosolvents on the Complexation of β-Cyclodextrin with Alkanols by Calorimetry at 298 K

Giuseppina Castronuovo, Vittorio Elia, Marcella Niccoli, Filomena Velleca

Journal of Inclusion Phenomena and Macrocyclic Chemistry > 2003 > 45 > 1-2 > 89-95

The formation of complexes between β-cyclodextrin and 1-alkanols hasbeen studied calorimetrically at 298 K in water and in concentrated aqueoussolutions of ethanol or urea. When a complex is formed, calorimetry enables thecalculation of both the enthalpy and the association constant, from which thefree energy and the entropy of the process can be obtained. The effects ofethanol and urea on the hydration...

article

Calorimetric studies of hydrophobic interactions of alkanols in concentrated aqueous solutions of glucose - Implications for the mechanism of protein stabilization by sugars

Giuseppina Castronuovo, Vittorio Elia, Marcella Niccoli, Filomena Velleca

Thermochimica Acta > 2002 > 389 > 1-2 > 1-9

Calorimetric measurements were carried out at 298K on concentrated aqueous solutions of glucose, ranging from 0 to 5molkg ^- ¹ , containing alkan-1-ols, alkane-1,2-diols and alkane-α,ω-diols from C ₂ to C ₇ . The purpose of this study is to obtain more information about the influence of glucose on hydrophobic hydration and interactions. The pair-wise interaction coefficients...

article

The Effects of Cosolvents on the Complexation of α-Cyclodextrin with Alkylated Substances. Calorimetric Studies at 25 °C

Giuseppina Castronuovo, Vittorio Elia, Marcella Niccoli, Filomena Velleca

Journal of Inclusion Phenomena and Macrocyclic Chemistry > 2002 > 44 > 1-4 > 229-234

The formation of complexes of α-cyclodextrin with 1,2-alkanediols, α,ω-alkanediols and some cycloalkanols has been studied calorimetrically at 25 °C in water, in 7 mol kg^-1 aqueous urea and in 3 mol kg^-1 aqueous glucose. When a complex is formed, calorimetry enables the calculation of both the enthalpy and the association constant, from which the free energy and the entropy of the process can be obtained...

article

Factors determining the formation of complexes between α-cyclodextrin and alkylated substances in aqueous solutions: a calorimetric study at 25 ^o C

Giuseppina Castronuovo, Vittorio Elia, Assunta Iannone, Marcella Niccoli, more

Carbohydrate Research > 2000 > 325 > 4 > 278 - 286

The formation of complexes of α-cyclodextrin with cycloalkanediols, monoalkylamines and 1-alkanols has been studied calorimetrically at 25 ^o C in water, in phosphoric acid, pH 1.3, and in phosphate buffer, pH 5.5, respectively. When a complex is formed, calorimetry enables the calculation of both the enthalpy and the association constant, from which the free energy and the entropy of the process...

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