Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV

Dunkerque, France

Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV

Dunkerque, France
SEARCH FILTERS
Time filter
Source Type

Mallard I.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV | Stade L.W.,University of Aalborg | Ruellan S.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV | Jacobsen P.A.L.,University of Aalborg | And 2 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2015

The functionalization of zeolite Y (Faujasite) with β-cyclodextrin (CD) was realized by using 3-glycidoxypropyltrimethoxysilane (GPTS) as linker. Two different strategies were followed: grafting of the linker on β-CD and then reacted with zeolite or grafting of the linker on zeolite and then reacted with β-CD. Obtained materials were characterized by several complementary methods including, focused ion beam-scanning electron microscopy-energy dispersive X-ray spectrometry (FIB-SEM-EDX), Thermogravimetric analysis and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmet-Teller (BET) analysis. The decrease in surface area compared to native zeolite indicated clogging of the zeolite pores while sorption capacities of functionalized zeolite toward two model pollutants (toluene and methyl orange) were greater than native zeolite. Moreover, the first strategy led to better sorption capacities than the second one. These new materials are potential sorbents for remediation purpose toward gaseous or aqueous effluent. © 2015 Elsevier B.V.


PubMed | Cheikh Anta Diop University and Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV
Type: | Journal: Talanta | Year: 2016

Herbicide metolachlor (MET) and insecticide buprofezin (BUP) were determined in natural waters by means of a newly-developed, simple and sensitive thermochemically-induced fluorescence derivatization (TIFD) method. The TIFD approach is based on the thermolysis transformation of naturally non-fluorescent pesticides into fluorescent complex O-phthalaldehyde-thermoproduct(s) in water at 70C for MET and at 80C for BUP. The TIFD method was optimized with respect to the temperature, pH, complex formation kinetic and pesticides concentrations. The limit of detection (LOD=0.8ngmL(-1) for MET and 3.0ngmL(-1) for BUP) and quantification (LOQ=2.6ngmL(-1) for MET and 9.5 ngmL(-1) for BUP) values were low, and the relative standard deviation (RSD) values were small (between 1.2% and 1.8%), which indicates a good analytical sensitivity and a great repeatability of TIFD method. Recovery studies were performed on spiked well, sea and draining waters samples collected in the Niayes area by using the solid phase extraction (SPE) procedure. Satisfactory recovery results (84-118%) were obtained for the determination of MET and BUP in these natural waters.


Gharib R.,Lebanese University | Greige-Gerges H.,Lebanese University | Fourmentin S.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV | Charcosset C.,University of Lyon | Auezova L.,Lebanese University
Carbohydrate Polymers | Year: 2015

Cyclodextrins (CDs) are cyclic oligosaccharides, consisting of glucopyranose units, which are able to form host-guest inclusion complexes with lipophilic molecules. The ability of CD to increase drug solubility may be used to increase drug entrapment in the aqueous compartment of liposomes and liposomes can protect CD/drug inclusion complexes until drug release. Liposomes are phospholipid vesicles composed of lipid bilayers enclosing one or more aqueous compartments. They have been widely used as safe and effective carriers for both hydrophilic and lipophilic drugs. However, lipophilic drugs incorporated in the membrane bilayers can be rapidly released, which limits the effectiveness of this drug delivery system. The coupling of both delivery systems by encapsulating CD/drug inclusion complex into liposomes is proposed to circumvent the drawbacks of each separate system. Here, we review the literature regarding the encapsulation of CD/drug inclusion complex into conventional, deformable and double loaded liposomes. The review highlights the characteristics of these systems and presents the advantages and disadvantages of each one. © 2015 Elsevier Ltd. All rights reserved.


PubMed | Lebanese University, University of Lyon and Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV
Type: | Journal: Carbohydrate polymers | Year: 2015

Cyclodextrins (CDs) are cyclic oligosaccharides, consisting of glucopyranose units, which are able to form host-guest inclusion complexes with lipophilic molecules. The ability of CD to increase drug solubility may be used to increase drug entrapment in the aqueous compartment of liposomes and liposomes can protect CD/drug inclusion complexes until drug release. Liposomes are phospholipid vesicles composed of lipid bilayers enclosing one or more aqueous compartments. They have been widely used as safe and effective carriers for both hydrophilic and lipophilic drugs. However, lipophilic drugs incorporated in the membrane bilayers can be rapidly released, which limits the effectiveness of this drug delivery system. The coupling of both delivery systems by encapsulating CD/drug inclusion complex into liposomes is proposed to circumvent the drawbacks of each separate system. Here, we review the literature regarding the encapsulation of CD/drug inclusion complex into conventional, deformable and double loaded liposomes. The review highlights the characteristics of these systems and presents the advantages and disadvantages of each one.


Kfoury M.,Lebanese University | Landy D.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV | Ruellan S.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV | Auezova L.,Lebanese University | And 2 more authors.
Beilstein Journal of Organic Chemistry | Year: 2016

Carvacrol and thymol have been widely studied for their ability to control food spoilage and to extend shelf-life of food products due to their antimicrobial and antioxidant activities. However, they suffer from poor aqueous solubility and pronounced flavoring ability that limit their application in food systems. These drawbacks could be surpassed by encapsulation in cyclodextrins (CDs). Applications of their inclusion complexes with CDs were reported without investigating the inclusion phenomenon in deep. In this study, inclusion complexes were characterized in terms of formation constants (Kf), complexation efficiency (CE), CD: guest molar ratio and increase in bulk formulation by using an UV-visible competitive method, phase solubility studies as well as 1H and DOSY 1H NMR titration experiments. For the first time, a new algorithmic treatment that combines the chemical shifts and diffusion coefficients variations for all guest protons was applied to calculate Kf. The position of the hydroxy group in carvacrol and thymol did not affect the stoichiometry of the inclusion complexes but led to a different binding stability with CDs. 2D ROESY NMR experiments were also performed to prove the encapsulation and illustrate the stable 3D conformation of the inclusion complexes. The structural investigation was accomplished with molecular modeling studies. Finally, the radical scavenging activity of carvacrol and thymol was evaluated by the ABTS radical scavenging assay. An improvement of this activity was observed upon encapsulation. Taken together, these results evidence that the encapsulation in CDs could be valuable for applications of carvacrol and thymol in food. © 2016 Kfoury et al; licensee Beilstein-Institut.


PubMed | Lebanese University and Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV
Type: | Journal: Beilstein journal of organic chemistry | Year: 2016

Carvacrol and thymol have been widely studied for their ability to control food spoilage and to extend shelf-life of food products due to their antimicrobial and antioxidant activities. However, they suffer from poor aqueous solubility and pronounced flavoring ability that limit their application in food systems. These drawbacks could be surpassed by encapsulation in cyclodextrins (CDs). Applications of their inclusion complexes with CDs were reported without investigating the inclusion phenomenon in deep. In this study, inclusion complexes were characterized in terms of formation constants (K f), complexation efficiency (CE), CD:guest molar ratio and increase in bulk formulation by using an UV-visible competitive method, phase solubility studies as well as (1)H and DOSY (1)H NMR titration experiments. For the first time, a new algorithmic treatment that combines the chemical shifts and diffusion coefficients variations for all guest protons was applied to calculate K f. The position of the hydroxy group in carvacrol and thymol did not affect the stoichiometry of the inclusion complexes but led to a different binding stability with CDs. 2D ROESY NMR experiments were also performed to prove the encapsulation and illustrate the stable 3D conformation of the inclusion complexes. The structural investigation was accomplished with molecular modeling studies. Finally, the radical scavenging activity of carvacrol and thymol was evaluated by the ABTS radical scavenging assay. An improvement of this activity was observed upon encapsulation. Taken together, these results evidence that the encapsulation in CDs could be valuable for applications of carvacrol and thymol in food.


PubMed | Lebanese University and Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV
Type: | Journal: Analytica chimica acta | Year: 2016

Formation of inclusion complexes with cyclodextrins (CDs) is known to enhance guest solubility in aqueous medium. Different techniques allow determining the evolution in solubility of individual guest compounds. However, examination of mixtures solubility encapsulated in CDs is still a challenge. This is mainly related to the difference in the response of mixture components to the applied technique or to the fact that most of the conventional methods examine the signal of an individual constituent of the mixture. Thus, applying current techniques may not reflect the behavior of the whole mixture. Here, we used for the first time Total Organic Carbon (TOC) analysis to explore and assess the efficiency of 2-hydroxypropyl--cyclodextrin (HP--CD) to enhance the solubility of natural complex mixtures such as essential oils (EOs). Phase solubility studies were performed for eleven EOs with HP--CD. The TOC method has provided good validation parameters for linearity, precision and accuracy. For further validation of the method, phase solubility studies were performed with HP--CD for eugenol, as a model EO component. The eugenol solubility was determined by UV-Visible and TOC analyses in order to compare the results. Data obtained from both methods were similar (p<0.05), thereby proving the effectiveness of the developed TOC method. Finally, the phase solubility diagrams of EOs showed that the solubilizing potential of CD increased proportionally with the decrease in EO intrinsic solubility. Results proved that TOC could be successfully applied to investigate CD/guest inclusion complexes and is expected to have a broad range of applications in the field of mixtures encapsulation.


PubMed | Lebanese University and Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV
Type: | Journal: Carbohydrate polymers | Year: 2015

Essential oils (EOs) are gaining great interest as alternatives for harmful synthetic food preservatives. Due to their volatile nature, they could be applied in food packaging to improve food quality and extend shelf-life. To provide long-term effects of EOs by increasing their retention and ensuring controlled release of their components, they could be encapsulated in cyclodextrins (CDs). Herein, the ability of six CDs to retain nine EOs and to bind their individual components was investigated. Retention capacities and binding abilities of CDs were assessed by static headspace-gas chromatography (SH-GC) using a new validated rapid method. The ability of CDs to generate controlled release systems was examined by multiple headspace extraction (MHE). Finally, radical scavenging activity of free and encapsulated EOs was evaluated. The highest retention capacity toward the studied EOs was obtained for -CD and its derivatives (69-78%). Also, -CD and its derivatives showed, with one exception, the highest Kf values for all the studied guests. In addition, encapsulation in CDs reduced the releasing rate of EO components (from 1.43 to 2.43-fold for -CD/Satureja montana EO used as a model). Furthermore, the inclusion complexes showed higher ABTS(+) scavenging capacity than the free EOs. Results confirmed the usefulness of CDs as encapsulant for EOs and should encourage their application in food and as part of active packaging systems.


Kfoury M.,Lebanese University | Auezova L.,Lebanese University | Ruellan S.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV | Greige-Gerges H.,Lebanese University | Fourmentin S.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV
Carbohydrate Polymers | Year: 2015

Inclusion complexes of estragole (ES) as pure compound and as main component of basil and tarragon essential oils (EOs) with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), randomly methylated-β-cyclodextrin (RAMEB), a low methylated-β-cyclodextrin (CRYSMEB) and γ-cyclodextrin (γ-CD) were characterized. Formation constants (Kf) of the complexes were determined in aqueous solution by nonlinear regression analysis using static headspace gas chromatography (SH-GC) and UV-visible spectroscopy. Solid inclusion complexes were prepared by the freeze-drying method for different CD:ES molar ratios and were characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). Inclusion complexes formation allowed the controlled release of ES. Moreover, increased DPPH radical scavenging activity and photostability of ES and ES containing EOs (ESEOs) were observed in the presence of CDs. These findings suggest that encapsulation with CDs could be an efficient tool to improve the use of ES and ESEOs in aromatherapy, cosmetic and food fields. © 2014 Elsevier Ltd.


Kfoury M.,Lebanese University | Auezova L.,Lebanese University | Greige-Gerges H.,Lebanese University | Fourmentin S.,Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV
Carbohydrate Polymers | Year: 2015

Abstract Essential oils (EOs) are gaining great interest as alternatives for harmful synthetic food preservatives. Due to their volatile nature, they could be applied in food packaging to improve food quality and extend shelf-life. To provide long-term effects of EOs by increasing their retention and ensuring controlled release of their components, they could be encapsulated in cyclodextrins (CDs). Herein, the ability of six CDs to retain nine EOs and to bind their individual components was investigated. Retention capacities and binding abilities of CDs were assessed by static headspace-gas chromatography (SH-GC) using a new validated "rapid method". The ability of CDs to generate controlled release systems was examined by multiple headspace extraction (MHE). Finally, radical scavenging activity of free and encapsulated EOs was evaluated. The highest retention capacity toward the studied EOs was obtained for β-CD and its derivatives (69-78%). Also, β-CD and its derivatives showed, with one exception, the highest Kf values for all the studied guests. In addition, encapsulation in CDs reduced the releasing rate of EO components (from 1.43 to 2.43-fold for β-CD/Satureja montana EO used as a model). Furthermore, the inclusion complexes showed higher ABTS+ scavenging capacity than the free EOs. Results confirmed the usefulness of CDs as encapsulant for EOs and should encourage their application in food and as part of active packaging systems. © 2015 Elsevier Ltd.

Loading Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV collaborators
Loading Unite de Chimie Environnementale et Interactions sur le Vivant UCEIV collaborators