Добірка наукової літератури з теми "Substances naturelles complexes"
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Статті в журналах з теми "Substances naturelles complexes"
Bouyahya, A., J. Abrini, Y. Bakri, and N. Dakka. "Les huiles essentielles comme agents anticancéreux : actualité sur le mode d’action." Phytothérapie 16, no. 5 (October 2018): 254–67. http://dx.doi.org/10.3166/s10298-016-1058-z.
Повний текст джерелаAchour, S., and S. Guergazi. "Incidence de la minéralisation des eaux algériennes sur la réactivité de composés organiques vis-à-vis du chlore." Revue des sciences de l'eau 15, no. 3 (April 12, 2005): 641–60. http://dx.doi.org/10.7202/705473ar.
Повний текст джерелаGaspar, Thomas, Claude Penel, and Hubert Greppin. "Approche analogique et réalités des phytohormones : des retards et des erreurs stratégiques?" Bulletin de la Société Royale des Sciences de Liège, 2016, 190–208. http://dx.doi.org/10.25518/0037-9565.6236.
Повний текст джерелаДисертації з теми "Substances naturelles complexes"
Bastos, de lemos e. silva Siguara. "Chimie et biosynthèse de substances naturelles hautement complexes de la biodiversité méditerranéenne." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS214.
Повний текст джерелаThis thesis aims at the study of the chemical and biogenetic origin of specialized guanidine-alkaloid metabolites produced by sponges from the Mediterranean Sea.The work is divided into three main parts: 1) isolation of alkaloids produced by sponges of the Poeciloscerida order; 2) biosynthesis of crambescin C1 by in-vivo 14C-feeding experiments with Crambe crambe sponge; 3) biomimetic synthesis of crambescin A2 448 and derivatives. The main focus of the thesis will be the family of cyclic-guanidine alkaloids "crambescins", produced by the red incrusting sponge Crambe crambe.These alkaloids were discovered in the early 90s and despite the large interest on their biological activities, ecological roles, and synthesis, their biosynthesis is still unknown.The only available biomimetic synthesis of crambescins was based on a fully polyketide origin hypothesis. Recently our groups suggested an alternative biosynthetic hypothesis in which the guanidine-core would be originated from a condensation between a guanidinated pyrrolidinium derived from arginine and a beta-keto fatty acid. Based on this hypothesis, we designed a biosynthesis experiment that inspired a biomimetic synthesis route to access the crambescins and derivatives. The insights from these studies are the first experimental conclusions about the biosynthesis of crambescins. Finally, this work leads to a better comprehension of the biochemistry involved in guanidine marine alkaloids of complex structures
Ahamada, Kadiria. "Stratégies biomimétiques en vue de la synthèse totale de deux substances naturelles polycycliques complexes : la bipléiophylline et l'haliclonine A." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA114807/document.
Повний текст джерелаOur work deals in the first part with a biomimetic synthesis of bipleiophyllin, an indolomonoterpenic alkaloid. The bipleiophyllin is the result of a complex anchorage of two identical indolic subunits on an aromatic platform. A general strategy for the biomimetic synthesis of bipleiophyllin consisting of i) the synthesis of the indolic unit pleiocarpamin and ii) the oxidation of 2,3-dihydroxybenzoic acid; was considered. Access to the complex skeleton of pleiocarpamin has been studied by different total synthesis strategies but also by hemisynthesis. Meanwhile this work, a study of the oxidation conditions of 2,3-dihydroxybenzoic acid including by electrochemistry, helped identify and characterize its oxidation potential and develop the required conditions to obtain its oxidized form. The second part is devoted to the biomimetic synthesis of a model compound, mimic of the central core of haliclonin A, an alkaloid of the family of manzamins. The synthesis of several precursors and the study of the key step consisting in a double nucleophilic addition to a 5,6-dihydropyridinium were done
Paillat, Lionel. "Application de la chromatographie planaire haute performance (HPTLC) à l'analyse des substances naturelles complexes à destination des arômes, parfums et de la cosmétique." Nice, 2012. http://www.theses.fr/2012NICE4104.
Повний текст джерелаThis work is dedicated to the application of high-performance thin-layer chromatography (HPTLC) for the analysis of plant extracts used in aroma, perfume and cosmetic industries. Different planar chromatographic methods were developed and validated for the quantification of natural compounds in plant matrices: quantification of nicotine in tobacco extracts, quantification of major phenolic compounds in vanilla fruits, beans and extracts and quantification of alcohols and acetates in vetiver extracts from Haiti. A fractionation scheme was developed for chemical separation of the metabolites in oleoresins; HPTLC, by its capacity to focus on specific metabolites, was used for phytochemical screening of the fractions. Fractionation of mate (Ilex paraguariensis St-Hil ) oleoresin allowed for the isolation of saponins enriched fraction which was characterized by HPTLC, HPLC-MS and NMR. 16 saponins were identified; 6 of them were never described in mate leaves. 4 genins were identified as to be ursolic, oleanolic and 23-hydroxyursolic acids as well as 3-hydroxy-24-nor-urs-4(23), 12-dien-28-oic acid, which was never documented. HPTLC and HPLC quantification allowed for the elucidation of 60 to 70 % of the extract and its valorization through its high content in polyphenols and saponins. Developed HPTLC methods were precise, sensitive and repeatable
Gilles, Laure. "Découverte et synthèse chimique d'odorants par des technologies innovantes." Electronic Thesis or Diss., Université Côte d'Azur, 2022. http://www.theses.fr/2022COAZ4100.
Повний текст джерелаThe perfumery industry in under constant pressure from national and international regulatory bodies as well and the demands of consumers to produce novel and safe organoleptic molecules via methods which are both durable and innovative. This constant drive for innovation pushes researchers towards diverse domains of the plant kingdom which contains numerous complex natural substances (CNS). At present these natural products are a source of ingredients, however, they are equally a source of inspiration for the chemist who may identify structures of interest to be synthesised with a high degree of control (chirality, quantity, quality, consistency), as well as structural analogues to provide an improvement of the olfactory properties (notes, intensity).This manuscript presents an extended analysis of the distillate of a concrete of the plant Ocimum gratissimum via GC-O complemented with GC-MS analysis. This study has also enlighted the chemical composition of the extract, characterisation of the poorly described (E)-methyl cinnamate chemotype, olfactory evaluation by a master perfumer and the identification of the principal olfactive compounds. This work simultaneously explores multistep asymmetric synthetic strategies in the aim of obtaining the different enantiomers of vetispira-2(11),6-dien-14-al. This compound is known to be an important component of agar wood essential oil and largely responsible for its particular odour. Currently no syntheses of this compound have been published. An FeCl3 catalysed acetylation of α,β-unsaturated compounds was optimised and applied to the synthesis of 24 different heterocyclic spirocycles, which are to be submitted to a master perfumer for the evaluation of their notes and olfactory interest
Bouges, Hélène. "Modifications enzymatiques de la composition de mélanges naturels complexes utilisés en parfumerie." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4024.
Повний текст джерелаIn the field of flavor and fragrance industry, the optimization of natural flavoring essential oils and extracts’ properties by biocatalysis is really interesting. In a context of sustainable chemistry, this research project is dedicated to the development of pure compounds, extracts and essential oils by enzymatic modifications. In this way, a bibliographic study has been carried out on the composition of the natural raw materials, their properties and the main biosynthetic pathways of the compounds present in the natural complex substances and some regulation elements. In the first place, according to a process of sustainable chemistry, the goal is to make healthier natural products while keeping their properties and their "naturalness". The detoxification in atranol and chloroatranol of the oak moss extract was carried out with the oak moss absolute by biocatalysis preserving their olfactory quality. Through an academic /industrial collaboration, protocols for monitoring biocatalytic transformations were established and implemented. In a third part, sustainable chemistry methodologies were used to propose new ingredients through the use of biotechnological processes based on the circular economy principle. The natural character has been preserved and the method allowed targeted transformations to develop interesting olfactory facets
Richieu, Antoine. "Synthèse totale de la vescaline, substance naturelle bioactive de la famille des ellagitannins C-arylglucosidiques." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0937/document.
Повний текст джерелаC-arylglucosidic ellagitannins are polyphenolic compounds biosynthesized through the secondary metabolism of various plants, in particular from the Fagaceae family such as oak and chestnut. Vescalin, which belongs to this class of plant polyphenols, displays interesting biological activities, with antiviral and antitumoral properties. More specifically, it inhibits topoisomerase 2α, a targeted enzyme in chemotherapy used in cancer treatment, and have also an activity against the cytoskeletal filamentous actin. Unique structure of vescalin displays a NonaHydroxyTriPhenoyl moiety (NHTP) linked to an open chain D-glucose with a C-arylglucosidic bond. The total synthesis of vescalin constitutes the main goal of this doctoral work. Synthetic routes employ in part chemical methods previously used for the total synthesis of 5-O-desgalloylepipunicacortein A in addition to new methodologies. Therefore, the C-arylglucosidation method and chemical yield have been improved and an efficient intramolecular terarylic coupling between a HexaHydroxyDiPhenoyl moiety (HHDP) and a galloyl unit has been developed. Taking advantage of the synthetic strategy elaborated for vescalin total synthesis, three additional C-arylglucosidic ellagitannins were obtained: punicacortein A, epipunicacortein A and castalin