Study of Some Zanthoxylum Species by Chemical and DNA Analysis Approaches.

The authentication and traceability of spices is a major concern for industrials and consumers. We focused on species from Zanthoxylum genera which are used for many different applications by local populations and also for trading as spices (dried pericarps or whole fruits). In this case, literature gives contradictory data about botanical names, and commercial labelling is often confusing. We studied commercial fruits pericarps extracts obtained by supercritical CO2 and analyzed them by GC/MS. The very complex volatile and semi volatile fractions composition of each extract is described. The barcoding method including molecular biology and phylogenetic analyses was also developed in order to check the commercial botanical identification of the raw material. This is a robust method to identify species in berries samples. We used one genetic marker to identify two Rutaceae clusters, including several species of Zanthoxylum genus. These results indicate that Fagara and Zanthoxylum groups could be considered as two different genera. Combination of chemical analysis and DNA analysis provides an original approach to increase chemical and botanical Zanthoxylum genus knowledge.

Development of new natural extracts.

For over the past 20 years, a remarkable development in the study and search of natural products has been observed. This is linked to a new market trend towards ecology and also due to new regulations. This could be a rupture, but also a real booster for creativity. Usually, in the flavor and fragrance field, creativity was boosted by the arrival of new synthetic molecules. Naturals remained the traditional, century-old products, protected by secrecy and specific know-how from each company. Regulatory restrictions or eco-friendly certification constraints like hexane-free processes triggered an important brainstorming in the industry. As a result, we developed new eco-friendly processes including supercritical CO2 extraction, allowing fresh plants to be used to obtain industrial flower extracts (Jasmine Grandiflorum, Jasmine Sambac, Orange blossom). These extracts are analyzed by GC, GC/MS, GCO, and HPTLC techniques. New or unusual raw materials can also be explored, but the resulting extracts have to be tested for safety reasons. Some examples are described.

Arylthio-substituted coronenes as tailored building blocks for molecular electronics.

The electron transport through molecules in molecular devices is typically influenced by the nature of the interfaces with the contacting electrodes and by the interactions between neighbouring molecules. It is a major goal of molecular electronics to adjust the electronic function of a molecular device by tailoring the intrinsic molecular properties and the interfacial and intermolecular interactions. Here, we report on the tunability of the electronic properties of coronene derivatives, namely dodecakis(arylthio)coronenes (DATCs), which are found to exhibit a three-dimensional aromatic system. Scanning tunnelling microscopy (STM), spectroscopy (STS) and simulations based on the density functional theory (DFT) are employed to characterize the structural and electronic properties of these molecules deposited on Au(111) surfaces. It is shown that modifications of the peripheral aryl-groups allow us to specifically affect the self-assembly and the charge transport characteristics of the molecules. Molecular assemblies like supramolecular wires with highly delocalized orbitals and single molecules with molecular "quantum dot" characteristics are obtained in this way.