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Saint-Jean-de-Braye, France

Claude B.,CNRS Institute of Organic and Analytical Chemistry | Viron-Lamy C.,LVMH Recherche Parfums et Cosmetiques | Haupt K.,Compiegne University of Technology | Morin P.,CNRS Institute of Organic and Analytical Chemistry
Phytochemical Analysis | Year: 2010

Introduction - Plant extracts are usually complex mixtures of various polarity compounds and their study often includes a purification step, such as solid-phase extraction (SPE), to isolate interest compounds prior analytical investigations. Molecularly imprinted polymers (MIPs) are a new promising type of SPE material which offer tailor-made selectivity for the extraction of trace active components in complex matrices. Numerous specific cavities that are sterically and chemically complementary of the target molecules, are formed in imprinted polymers. A molecularly imprinted polymer (MIP) was synthesised in order to trap a specific class of triterpene, including betulin and betulinic acid from a methanolic extract of plane bark. Methodology - Imprinted polymers were synthesised by thermal polymerisation of betulin as template, methacrylic acid (MAA) or acrylamide (AA) as functional monomer, ethylene glycol dimethacrylate as crosslinking agent and chloroform as porogen. Afterwards, MAA- and AA-MIPs were compared with their non-imprinted polymers (NIPs) in order to assess the selectivity vs betulin and its derivatives. Recovered triterpenes were analysed by HPLC during MIP-SPE protocol. Results - After SPE optimisation, the MAA-imprinted polymer exhibited highest selectivity and recovery (better than 70%) for betulin and best affinity for its structural analogues. Thus, a selective washing step (chloroform, acetonitrile) removed unwanted matrix compounds (fatty acids) from the SPE cartridge. The elution solvent was methanol. Finally, the MAA-MIP was applied to fractionate a plane bark methanolic extract containing betulin and betulinic acid. Conclusion - This study demonstrated the possibility of direct extraction of betulin and its structural analogues from plant extracts by MIP technology. Copyright © 2009 John Wiley & Sons, Ltd. Source

El Abdellaoui S.,CNRS Institute of Organic and Analytical Chemistry | Destandau E.,CNRS Institute of Organic and Analytical Chemistry | Toribio A.,CNRS Institute of Organic and Analytical Chemistry | Elfakir C.,CNRS Institute of Organic and Analytical Chemistry | And 5 more authors.
Analytical and Bioanalytical Chemistry | Year: 2010

Kalanchoe pinnata (Lam.) Pers. (syn. Bryophyllum pinnatum; family Crassulaceae) is a popular plant used in traditional medicine in many temperate regions of the world and particularly in South America. In Guyana, the leaves are traditionally used as an anti-inflammatory and antiseptic to treat coughs, ulcers, and sores. The purpose of this study was to implement a method for targeting and identifying molecules with antimicrobial activity, which could replace chemical preservatives in cosmetic applications. The leaves were extracted by a method based on pressurized liquid extraction (PLE), using different solvents. A study of antimicrobial activity and cytotoxicity tests were performed to select the most interesting extract. To isolate one or more active molecules, the selected crude extract was fractionated by centrifugal partition chromatography (CPC) and then antimicrobial activity and cytotoxicity of each fraction were tested under the same procedure. The last step consisted of identifying the main compounds in the most active fraction by LC-MS/MS. © 2010 Springer-Verlag. Source

Alves M.-H.,University of Pau and Pays de lAdour | Sfeir H.,University of Pau and Pays de lAdour | Tranchant J.-F.,LVMH Recherche Parfums et Cosmetiques | Gombart E.,LVMH Recherche Parfums et Cosmetiques | And 4 more authors.
Biomacromolecules | Year: 2014

The present work shows the synthesis of amphiphilic polymers based on the hydrophilic dextran and the hydrophobic terpenes as renewable resources. The first step concerns the synthesis of functional terpene molecules by thiol-ene addition chemistry involving amino or carboxylic acid thiols and dihydromyrcenol terpene. The terpene-modified polysaccharides were subsequently synthesized by coupling the functional terpenes with dextran. A reductive amination step produced terpene end-modified dextran with 94% of functionalization, while the esterification step produced three terpene-grafted dextrans with a number of terpene units per dextran of 1, 5, and 10. The amphiphilic renewable grafted polymers were tested as emulsifiers for the stabilization of liquid miniemulsion of terpene droplets dispersed in an aqueous phase. The average hydrodynamic diameter of the stable droplets was observed at about 330 nm. © 2013 American Chemical Society. Source

Boularas M.,University of Pau and Pays de lAdour | Gombart E.,LVMH Recherche Parfums et Cosmetiques | Tranchant J.-F.,LVMH Recherche Parfums et Cosmetiques | Billon L.,University of Pau and Pays de lAdour | Save M.,University of Pau and Pays de lAdour
Macromolecular Rapid Communications | Year: 2015

This article reports a rational strategy for preparing smart oligo(ethylene glycol)-based hybrid microgels loaded with high content of homogeneously distributed preformed magnetic nanoparticles (NPs) (up to 33 wt%). The strategy is based on the synthesis of biocompatible multiresponsive microgels by precipitation copolymerization of di(ethylene glycol) methyl ether methacrylate, oligo(ethylene glycol) methyl ether methacrylate, methacrylic acid, and oligo(ethylene glycol)diacrylate. An aqueous dispersion of preformed magnetic NPs is straightforwardly loaded into the microgels. Robust monodisperse thermoresponsive magnetic microgels are produced, exhibiting a constant value of the volume phase transition temperature whatever the NPs content. The homogeneous microstructure of the initial stimuli-responsive biocompatible microgels plays a crucial role for the design of unique well-defined ethylene glycol-based thermoresponsive hybrid microgels. (Chemical Equation Presented). © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. Source

Boularas M.,University of Pau and Pays de lAdour | Deniau-Lejeune E.,University of Pau and Pays de lAdour | Alard V.,LVMH Recherche Parfums et Cosmetiques | Tranchant J.-F.,LVMH Recherche Parfums et Cosmetiques | And 2 more authors.
Polymer Chemistry | Year: 2016

Multi-responsive biocompatible microgels with long term stability were synthesized by precipitation copolymerization of oligo(ethylene glycol) methyl ether methacrylate (OEGMA), di(ethylene glycol) methyl ether methacrylate (MEO2MA), methacrylic acid (MAA) and crosslinkers in aqueous dispersed media. Different crosslinkers, i.e. ethylene glycol dimethacrylate (EGDMA), oligo(ethylene glycol) diacrylate (OEGDA) or N,N-methylenebisacrylamide (MBA) were used for the synthesis of the microgels. The present work investigates for the first time how the inner structure of the biocompatible P(MEO2MA-co-OEGMA-co-MAA) microgels impacts their swelling-to-collapse transition in response to both temperature and pH. The EGDMA-crosslinked microgels obviously differ from the OEGDA- and MBA-crosslinked microgels. The OEGDA-crosslinked P(MEO2MA-co-OEGMA-co-MAA) microgels are ideal candidates to prepare robust thermoresponsive hybrid magnetic microgels by a straightforward method involving simple loading of pre-formed magnetic nanoparticles (NP) in the absence of NP release. The crosslinker distribution is at the origin of differences in the distribution of iron oxide nanoparticles. The homogeneous distribution of both MAA units and the OEGDA crosslinker in the P(MEO2MA-co-OEGMA-co-MAA) microgels ensured a sharp VPTT of microgels over a wide range of pH values (from pH 4 to 9) and the retention of the thermoresponsiveness of the corresponding hybrid microgels for the different contents of magnetic nanoparticles (from 7 to 33 wt% of γ-Fe2O3versus polymer). Turbidimetry measurements highlighted the unique stability of the hybrid microgels over several hours even for the highest content of iron oxide nanoparticles. © The Royal Society of Chemistry 2016. Source

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