Search

With the objective to develop a scent database that could be used for perfume and cosmetics applications, a comparative analysis of the floral profiles close to one hundred odorous flowering plants found in Reunion Island has been undertaken for the last few years in our laboratory. A part of this work relating to three Hedychium species (the well-known H. coronarium but also H. flavescens and H. gardnerianum) is presented here. To achieve this, the solid phase microextraction (SPME) on living flowers coupled to GC/MS was used. A total of 53 volatiles were identified belonging to aliphatic ketones, monoterpenes (hydrocarbons and oxygenated), sesquiterpenes (hydrocarbons and oxygenated), phenylpropanoids/benzenoids and miscellaneous. The phenylpropanoid/benzenoid and terpenoid classes were the main volatile classes. (E)-b-ocimene, linalool, (E,E)-a-farnesene, (E)-nerolidol, methyl benzoate, methyl salicylate, (E)-isoeugenol and indole were the major compounds detected. Results also revealed significant aroma variation among the different flowers.

International audience; Dodonea viscosa(L.) Jacq from Reunion Island (Indian Ocean) was investigated for itsleaf essential oil composition. The plant was extracted by hydrodistillation and its essential oilanalysed by gas chromatography coupled to mass spectrometry. This study revealed that oxygenatednor-diterpenes and diterpenes were one of the major chemical classes (>50%) mainly consisting ofthree modified cyclopropylclerodanes containing a bicyclo[5.4.0]undecane ring system: one newfuranoid norditerpene, dodovisate C, and two furanoid diterpenes, the known methyl dodovisate Aand the new methyl iso-dodovisate A. These three compounds were isolated by liquid chromatographyand their structures established on the basis of spectroscopic studies. The absolute configurationof dodovisate C was elucidated through a joint experimental and theoretical (B3LYP/6-311+G(d,p))electronic circular dichroism study. The relative configurations of methyl dodovisate A and methyliso-dodovisate A were determined using linear regressions of theoretical chemical shifts versusexperimental values with the (B3LYP/6-311+G(d,p)) method.

International audience; no abstract

International audience; Sur les 22 plantes de La Réunion inscrites à la Pharmacopée française entre mai 2012 et janvier 2016, 20 plantes sont en Liste A : Antirheaborbonica J.F. Gmel. (Rubiaceae), Aphloia theiformis (Vahl) Benn. (Aphloiaceae), Ayapana triplinervis (Vahl) R. M. King et H.Rob. (Asteraceae),Coffea mauritiana Lam. (Rubiaceae), Dodonaea viscosa (L.) Jacq. (Sapindaceae), Hubertia ambavilla var. ambavilla (Asteraceae),Hypericum lanceolatum Lam. subps. lanceolatum (Hypericaceae), Jumellea fragrans (Thou) Schltr.(Orchidaceae), Leucas lavandulifoliaSm. (Lamiaceae), Mussaenda arcuata Poir. (Rubiaceae), Nuxia verticillata Lam. (Stilbaceae), Olea europaea subsp. cuspidata (Wall. ex G. Don)Cif. (Oleaceae), Olea lancea Lam. (Oleaceae), Phyllanthus casticum P. Willemet (Phyllanthaceae), Pittosporum senacia Putt. subsp. senacia(Pittosporaceae), Psiloxylon mauritianum (Bouton ex Hook. f.) Baill.(Psiloxilaceae), Secamone volubilis (Lam.) Marais (Apocynaceae),Sigesbeckia orientalis L. (Asteraceae), Syzygium cumini (L.) Skeels (Myrtaceae), Vepris lanceolata G. Don (Rutaceae). Une plante estinscrite en Liste B : Ochrosia borbonica J.F. Gmel.(Apocynaceae). Une plante, Turraea thouarsiana Cavaco & Kerauden (Meliaceae), estinscrite sur les deux listes, en Liste A pour l’usage externe et en Liste B pour l’usage interne.

International audience; no abstract

International audience; no abstract

International audience; no abstract

International audience

International audience; Working on natural substances, part of the research of the LCSNSA (Chemistry Laboratory of Natural Substances and Food Sciences) is devoted to volatile compounds from plants. The objectives are multiples and can be summarized in four points:(1) Research of bioactive molecules(2) Chemotaxonomic studies(3) Applications in perfume industry(4) Plant-insect interactionsEach of these four points will be discussed and illustrated by one or several examples of research projects conducted in the LCSNSA. The first two points exclusively concern volatile compounds generated by essential oils extracted from endemic or indigenous plants of Reunion, Mauritius, Madagascar and Comoros islands. The two last points are dedicated to volatiles found in the airspace (headspace) surrounding above-ground plant parts (flowers and fruits).This communication will also present a selection of sampling methods for volatile compounds that range from conventional, inexpensive, solvent-free, quick sampling methods to innovative method; as well as an overview of detection and identification methods of volatiles including GC-FID and GC-MS.

International audience; no abstract

International audience

International audience; Le Laboratoire de Chimie des Substances Naturelles et des Sciences des Aliments (LCSNSA) et l’Unité Mixte de Recherche C53 « Peuplement Végétaux et Bioagresseurs en Milieu Tropical (PVBMT) sont impliqués depuis 2005 dans un vaste programme relatif à la gestion et à la conservation de la biodiversité de l’île de la Réunion, haut lieu (hotspot) de la biodiversité mondiale. Dans ce cadre, ils ont mis en place un important projet de reconnaissance et de classification des plantes endémiques de l’île. Ce projet s’inscrit dans le domaine de l’écologie évolutive, dont la finalité est de mettre en évidence l’influence des mécanismes de l’évolution (sélection naturelle, mutation, hasard, migration…) sur le devenir des populations végétales et animales, leur type d’organisation et leur mode d’adaptation à l’environnement. Afin d’aboutir à une classification juste et précise des espèces végétales endémiques de l’île, le choix des chercheurs s’est fixé sur la mise en œuvre d’une étude scientifique combinant à la fois des données chimiques, botaniques et de phylogénie biomoléculaire.Ce vaste projet a débuté avec l’étude des espèces des genres Psiadia (Astéracées) et Melicope (Rutacées). L’analyse de leurs huiles essentielles a conduit en particulier à l’isolement et l’identification par spectrométrie de masse et résonance magnétique nucléaire mono- et bidimensionnelle de trois nouveaux terpènes : un monoterpène acétylé dérivé du alpha-pinène, l’acétate de 6-(7,7-diméthyl-2-méthylène-bicyclo[3.1.1])heptanoyle (1) ; un alcool sesquiterpénique au squelette tricyclique inhabituel, le 6,6,8,9-tétraméthyl-tricyclo[3.3.3.0]undéc-7-én-2-ol (2) ; et un sesquiterpène dioxygéné, le 2-hydroxy-6,10-diméthyl-6-vinylundéca-2,9-dièn-4-one (mélicopénol) (3). Les composés (1) et (2) ont été détectés en forte proportion dans les huiles essentielles de quatre des espèces du genre Psiadia (P. anchusifolia, P. argentea, P. boivinii et P. salaziana). Le composé (3) quant à lui, constitue le composé majoritaire de l’huile essentielle de Melicope obscura.En raison de leur forte proportion et de l’originalité de leur structure, il a été envisagé pour ces trois nouveaux composés, la possibilité d’un rôle de marqueurs chimiotaxonomiques.

International audience; The strategy of the Chemistry Laboratory of Natural Substances and Food Sciences, (LCSNSA) has always been to explore the potential of natural products from Reunion Island and the Indian Ocean area. For many years, the separation, purification, structure elucidation and biological evaluation of new molecules extracted from plants have been the favourite target of the laboratory because of their pharmaceutical, nutritional and cosmetic uses. In a context where medicinal plants are still widely used, especially in the French overseas territories, with a cultural, geographical and economical environment rapidly changing, a trans-disciplinary study of this particular biodiversity is fully relevant. In Reunion Island, contrary to many tropical countries, there is a real choice between modern and traditional medicine. More than a medical treatment, traditional medicine is a form of aid and an indispensable complement to western medicine. Many tea-herbalists sell various medicinal plants on the market places and propose several preparations such as decoctions, infusions, etc. Moreover, Reunion Island is one of the biodiversity hotspots of the world and offers a reservoir for the identification of new molecules for a multitude of applications. So, in the field of medicinal plants, the main objective of our lab’s work is to discover, characterise and eventually design selective bioactive compounds from Reunion plant species for the evaluation of the potentialities in species with highest value

International audience; no abstract

International audience; no abstract

International audience; no abstract

International audience; no abstract

International audience; no abstract

International audience; no abstract

International audience; no abstract

International audience

International audience; Molasses are produced together with granulated sugar. Three kinds of molasses are obtained during fractional crystallization : A, B, C molasses issued respectively from the first, the second and the third step of crystallization. Several parameters as the sucrose inversion, the presence of aminoacids, of water, of mineral salts, the alkaline pH, the sugar process duration (3 days) and the high temperature (90°C) favour Maillard reactions. These reactions generate coloured macromolecules and heterocycles that have a strong olfactive impact despite a low concentration. On account of the olfactive notes (Vernin, 1979) reminding «grilled», «roasted», «caramel», «burn» smells, the detection and the quantification of volatile compounds are made. The chemical composition and the potential uses in food formulations are correlated.Twenty four A, B and C molasse samples were collected from Bois Rouge sugar industry (Saint André, Reunion Island) and stored at –18°C temperature until analysis.Ice cream, sweet buns, butter cakes were made according to standard formulas. 10% to 20% of sugar quantity were substituted or added by A, B, C molasses. The traditional formulas and the new formulas were compared by tests about physicochemical and sensorial parameters.In all cases, molasses change sensorial aspects of foods. Among molasses, the C molasse is the most enriched in Maillard reaction products that act the more upon aromatic notes and colouring. Differentiation between the molasses is possible in the formulated foods. Instead of uses in animal foods or substrate of alcoholic fermentations, molasses could be considered as interesting sources of flavourings.