Antibacterial Activity of Daucus crinitus

The essential oils from the aerial parts of Daucus crinitus Desf. were analyzed at three developmental stages (early vegetative, early flowering, and full flowering). Oil yield was found to vary depending on the stage of development, and the highest content of oil (0.15% w/w) was obtained at full flowering. The chemical composition of essential oils studied by GC and GC-MS showed a total of 71 compounds: 27 aliphatic compounds, 18 sesquiterpene hydrocarbons, 9 hydrocarbons monoterpene, 5 oxygenated monoterpenes, 5 phenolic compounds, 4 oxygenated sesquiterpenes, 2 oxygenated diterpenes, and 01 diterpene hydrocarbons. Whatever the analyzed stage, phenolic compounds were the most abundant group. Their level significantly increased during ripening and varied from 36.4 to 82.1%. Antimicrobial activities of oils were tested on four different microorganisms. The oils of various phenological stages showed high activity against Candida albicans (30 mm) and Staphylococcus aureus (11–28 mm) bacteria strains which are deemed very dangerous and very difficult to eliminate. Thus, they represent an inexpensive source of natural antibacterial substances that may potentially be used in pathogenic systems

Characterization of volatile compounds of Daucus crinitus Desf. Headspace Solid Phase Microextraction as alternative technique to Hydrodistillation

<p>Abstract</p> <p>Background</p> <p>Traditionally, the essential oil of aromatic herbs is obtained using hydrodistillation (HD). Because the emitted volatile fraction plays a fundamental role in a plant's life, various novel techniques have been developed for its extraction from plants. Among these, headspace solid phase microextraction (HS-SPME) can be used to obtain a rapid fingerprint of a plant's headspace. <it>Daucus crinitus </it>Desf. is a wild plant that grows along the west coast of Algeria. Only a single study has dealt with the chemical composition of the aerial part oils of Algerian <it>D. crinitus</it>, in which isochavicol isobutyrate (39.0%), octyl acetate (12.3%), and β-caryophyllene (5.4%) were identified. Using GC-RI and GC-MS analysis, the essential oils and the volatiles extracted from separated organs of <it>D. crinitus </it>Desf. were studied using HS-SPME.</p> <p>Results</p> <p>GC-RI and GC-MS analysis identified 72 and 79 components in oils extracted using HD and in the volatile fractions extracted using SPME, respectively. Two types of essential oils were produced by the plant: the root oils had aliphatic compounds as the main component (87.0%-90.1%), and the aerial part oils had phenylpropanoids as the main component (43.1%-88.6%). HS-SPME analysis showed a more precise distribution of compounds in the organs studied: oxygenated aliphatic compounds were well represented in the roots (44.3%-84.0%), hydrocarbon aliphatic compounds were in the leaves and stems (22.2%-87.9%), and phenylpropanoids were in the flowers and umbels (47.9%-64.2%). Moreover, HS-SPME allowed the occurrence of isochavicol (29.6 - 34.7%) as main component in <it>D. crinitus </it>leaves, but it was not detected in the oils, probably because of its solubility in water.</p> <p>Conclusions</p> <p>This study demonstrates that HD and HS-SPME modes could be complimentary extraction techniques in order to obtain the complete characterization of plant volatiles.</p

Antifungal activity of essential oils of three aromatic plants from western Algéria against five fungal pathogens of tomato (Lycopersicon esculentum Mill)

The antifungal effect of the essential oils from Thymus capitatus L., Daucus crinitus Desf. and Tetraclinis articulate Vahl., aerial parts was evaluated in vitro against five phytopathogenic fungi of tomato (Fusarium oxysporum, Alternaria solani, Aspergillus niger, Penicillium sp1 and Penicillium sp2). Our results showed that among the three plant species tested, T. capitatus oil was the most potent antifungal against the fungi (inhibition of mycelial growth of 100 % at a concentration of 2 µg mL-1). Furthermore, the essential oil of T. articulata was also effective against F. oxysporum, A. solani, A. niger, Penicillium sp1 and Penicillium sp2 with an inhibition of mycelial growth greater than 57 % at a concentration of 5 µg mL-1. D. crinitus essential oil was less effective. T. capitatus essential oil was dominated by carvacrol (69.6 %) and p-cymene (12.4 %). The isochavicol isobutyrate (44.9 %) and isochavicol 2-methylbutyrate (9.7 %) were the major compounds in D. crinitus essential oil, while the most abundant compounds in T. articulata were α-pinene (32.0 %), cedrol (11.0 %) and 3-carene (9.6 %).The plant essential oils were found to be an effective antifungal against of mycelial growth and, therefore, can be exploited as an ideal treatment against disease rot of tomato or as a new potential source of natural additives for the food and/or pharmaceutical industries

Analyse des mélanges complexes de volatils issus des végétaux.

This work is a collection of my teaching activities and postdoctoral researches carried out within the laboratory "Chimie des Produits Naturels" (CPN) and the 'Natural resources' research project supported by the UMR CNRS 6134 "Environmental Sciences" of the University of Corsica Pasquale Paoli. The works concern the characterization of aromatic and medicinal plants (AMP) and products of agriculture through the volatile complex mixtures that are derived. These complex mixtures are essential oils, hydrosols, solvent extracts and volatile fractions. The different steps of the analytical sequence were discussed, the choice of plants and their sampling, the sample preparation, analysis, interpretation of the results using the statistical tool and their enhancement through the research of active molecules. The first part deals with the characterization of the essential oils, hydrosols, solvent extracts and volatile fractions from AMP and the aromas of olive-oils and citrus juices. To do this, we examined the potential of alternative methods to hydrodistillation, such as microwave-assisted extraction and Solid Phase MicroExtraction. The analysis is performed in the laboratory CPN using chromatographic techniques as Gas Chromatography (GC) for quantification and GC coupled with Mass Spectrometry (GC/MS) for the identification of the constituents. We have optimized the analytical sequence using complementary techniques such as column chromatography, SM using chemical ionization mode and the Nuclear Magnetic Resonance for the identification of missing references libraries molecules. The second part concerns the development of a new research axis which aims to highlight the active compounds through the study of antibacterial and antifungal activities of essential oils and plant extracts. We have highlighted the biological properties of essential oils and extracts against bacteria involved in food borne illness and nosocomial infections. The last part is developing the prospects aimed at strengthening the work on the AMP and agricultural products of Corsica by exploring new matrices (polar fraction) and new extraction techniques. The valorization of plant complex mixtures by the search for new antibiotics surpassing the mechanisms of resistance of bacteria and of new antioxidants remains scientific challenge for the future.Ce travail constitue un recueil des mes activités d'enseignement et de recherche postdoctorales réalisées au sein du laboratoire " Chimie des Produits Naturels " (CPN) dans le cadre du projet de recherche " Ressources Naturels " soutenu par l'UMR CNRS 6134 " Sciences de l'Environnement " de l'Université de Corse Pasquale Paoli. Les travaux concernent la caractérisation des Plantes aromatiques et médicinales (PAM) et des produits de l'agroalimentaire au travers des mélanges complexes volatils qui en sont issus. Ces mélanges complexes sont des huiles essentielles, des hydrolats, des extraits aux solvants et des fractions volatiles. Les différentes étapes de la séquence analytique ont été examinées à savoir, le choix des végétaux et leur échantillonnage, la préparation de l'échantillon, son analyse proprement dite, l'interprétation des résultats au moyen de l'outil statistique et leur valorisation au travers de la recherche de principes actifs. La première partie vise à caractériser les huiles essentielles, les hydrolats, les extraits aux solvants et les fractions volatiles issus de PAM et ainsi que les arômes des huiles d'olives et de jus d'agrumes. Pour cela, nous avons examiné les potentialités de méthodes dites alternatives à l'hydrodistillation, méthode conventionnelle pour l'obtention des huiles essentielles et des hydrolats, telles que l'extraction assistée par micro-ondes et la MicroExtraction en Phase Solide. L'analyse proprement est réalisée au laboratoire CPN à l'aide de techniques chromatographiques telles que la Chromatographie en Phase Gazeuse (CPG) pour la quantification et la CPG couplée à la Spectrométrie de Masse (CPG-SM) pour l'identification des constituants des mélanges. Nous avons optimisé la séquence analytique en utilisant la complémentarité des techniques telles que la chromatographie sur colonne, l'utilisation de la SM en mode ionisation chimique et de la Résonance Magnétique Nucléaire pour l'identification de molécules absentes des bibliothèques de références. La deuxième partie concerne le développement d'un axe de recherche nouveau qui vise à mettre en évidence des principes actifs au travers de l'étude des propriétés antibactériennes et antifongiques des huiles essentielles et des extraits de végétaux. Nous avons mis en évidence les propriétés biologiques d'huiles essentielles et d'extraits sur un certain nombre de bactéries impliquées dans des infections nosocomiales et alimentaires. La dernière partie développe les perspectives de travail qui visent à renforcer les travaux sur les PAM et sur les produits identitaires de l'agroalimentaire produits en Corse en explorant de nouvelles matrices d'études (fraction lourde) et de nouvelles techniques d'extraction. La valorisation des mélanges complexes issus des végétaux par la recherche de nouveaux antibiotiques surpassant les mécanismes de résistance des bactéries et de nouveaux antioxydants reste un challenge scientifique d'avenir

First order Markov chain model for generating synthetic typical days series of global irradiation in order to design PV stand alone systems.

International audienc

Decentralized wind energy systems providing small electrical loads in remote area

International audienc

Stochastic study of hourly solar radiation in Corsica by using a Markov model

International audienc

Spectral Data of Two New Asymmetric Sesquiterpene Alcohols: (14R)-β-Oplopenol and (14S)-β-Oplopenol

Abstract: The epimeric sesquiterpene alcohols (14R)-β-oplopenol and (14S)-β-oplopenol were obtained by LiAlH4 reduction of β-oplopenone. The complete 1 H- and 13 C-NMR assignments of these two new sesquiterpene alcohols have been made using 1D and 2D NMR techniques, including COSY, NOESY, HSQC, HMBC experiments

Forecasting and simulating wind speed in Corsica by using an autoregressive model

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New advances in the volatile metabolites of Frullania tamarisci

International audienceThe chemical composition of Frullania tamarisci essential oil from Corsica was investigated using GC-FID, GC-MS and NMR analyses. The essential oil compositions were further studied analyzing samples prepared from three different Corsican locations and during a seasonal vegetative cycle. 40 components, which accounted for 78.3-89.8% of the total amount of F. tamarisci essential oils were identified. The main components were tamariscol coeluted with pacifigorgiol (30.4-41.5%), germacra-1(10)E,5E-dien-11-ol (3.6-7.1%), gamma-cylocostunolide (1.8-20.1%), gamma-dihydrocyclocostunolide (1.2-8.0%) and frullanolide (1.7-4.9%). Among them, germacra-1(10)E,5E-dien-11-ol was never reported in the Frullania genus and pacifigorgiol, a tamariscol GC-overlapped compound, was for the first time reported in Bryophytes. Finally using 1D and 2D NMR experiments, we reported gamma-dihydrocyclocostunolide as a new natural compound. Two Corsican F. tamarisci essential oils with different GC profiles were assessed for their phytotoxic behavior against onion seeds and seedling in order to evaluate their capacity to inhibit germination and alter the development of plantlets. According to the essential oil-compositions, a stimulation of the onion seedling was observed when sesquiterpene lactones amount was higher, whilst the inhibition of roots growth occurs when sesquiterpene alcohols were predominantly