Chemical Composition of Distilled Essential Oils and Hydrosols of Four Senegalese Citrus and Enantiomeric Characterization of Chiral Compounds

Peels of four local Citrus species (Citrus sinensis L. Obsbeck, Citrus reticulata Blanco, Citrus maxima Burm. and Citrus aurantifolia christm.) grown in a same locality under the same climatic conditions were subjected to steam distillation. The essential oils and floral waters obtained were analyzed by gas chromatography coupled with a flame ionization detector (CPG-FID) and by gas chromatography coupled to a mass spectrometer (CPG-MS). The essential oils yields were ranged between 0.2 and 0.7 %. The qualitative and quantitative analyses show 74 compounds in all oils samples. The oils were largely dominated by hydrocarbon monoterpenes with limonene as major compound (91.5-94.0 %; 90.4-93.4 %; 77.7-93.7 % and 34.8-51.2 %) in oils from Citrus sinensis, Citrus reticulata, Citrus maxima and Citrus aurantifolia, respectively. In addition to limonene, oils of Citrus aurantifolia contained high amounts of β-pinene (6.8-14.4 %), pcymene (5.8-12.2 %), γ-terpinene (0.3 -7.4 %), neral (1.5-9.4 %), geraniol (1.9-12.7 %). Although presenting the same major compound (limonene), the oils had compositions that were qualitatively and quantitatively different. The enantiomeric analyses showed that the chiral major compounds were (R) - (+) - limonene, (S) - (-) – limonene, (1S) - (-) -β-pinene, (1R)-(+)-β-pinene and (S) - (+) - carvone. The hydrosols analyzed were composed of oxygenated compounds and did not have the same major compound. A qualitative and quantitative difference in chemical composition was noted between the Hydrosols.WBI-Sénégal n ° 2: Production d’huiles essentielles à partir des plantes locales: expérimentation, adaptation et diffusion de technologies »

Immuno-Glyco-Imaging in Plant Cells: Localization of Cell Wall Carbohydrate Epitopes and Their Biosynthesizing Enzymes

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Activités antioxydante et insecticide d’huiles essentielles de Mentha arvensis L. du Sénégal

peer reviewedThis work is part of the global context of valorization of the biodiversity of aromatic plants from Senegal. The aim of the study is to determine the chemical composition of essential oils (EOs) of Mentha arvensis L. and to evaluate their antioxidant and insecticidal activities. For this purpose, leaves of M. arvensis were harvested in Dakar region, Senegal and dried in the shade. EOs were extracted by steam distillation from dried leaves and analyzed by gas chromatography (GC) coupled to a flame ionization detector (FID) and a mass spectrometer (MS). The antioxidant activity of EOs was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method while the insecticidal activity was tested by fumigation against Sitophilus zeamais(Motsch.). The results revealed that EOs were dominated by menthol (68.4%), menthyl acetate (16.9%) and menthone (5.0%). The antioxidant activity assay showed that the inhibition increased with the concentration: 38%, 57% and 73% for 10, 25 and 50 mg/ml, respectively; the IC50 was of 19.5 mg/ml. The oils were also effective as insecticide. Mortalities were low after 24 hours and increased strongly after 48 hours with a maximum of 92%. They reached a maximum of 98% for 5 and 25 µl and 100% for 50 and 75 µl after 72 hour

CHEMICAL COMPOSITION OF ESSENTIAL OILS AND FLORAL WATERS OF EUCALYPTUS CAMALDULENSIS (DEHN) FROM TWO LOCATIONS IN SENEGAL

peer reviewedEucalyptus camaldulensisDehnh leaves from two locations in Senegal (Dakar and Saint Louis) were dried for 14 and 21 days prior to distillation of essential oils by steam distillation and extraction of floral water. Essential oil yields were 0.7 to 2.0%. Oils were analyzed by gaschromatography coupled to a flame ionization detector (GC-FID) and by gas chromatography coupled to a mass spectrometer (GC-MS) equipped with methyl-phenyl–polysiloxane 5% column. Floral waters chemical composition was analyzed by GC-FID and GC-MS equipped with a polar column (VF-Wax ms). Results showed qualitative and quantitative differences in composition between oils from Hann (Dakar) and Bango (Saint Louis). The main constituents of oils were hydrocarbon monoterpenes with 80.9-83.0% for Hann (Dakar) and 51.5-50.6% for Bango (Saint-Louis). Dakar oils contained α-phellandrene as the major compound, with 45.3% and 47.7% after 14 and 21 days of drying, respectively. Other compounds such as p-cymene, α-pinene and 1,8-cineole were identified. The Saint-Louissample showed a very high content of β-phellandrene after 14 and 21 days of drying respectively, and α-pinene and p-cymene was also noted. Furthermore, the floral waters analysis revealed high concentrations of oxygenated compounds whose major part was present in oils. It was also noted qualitative and quantitative differences in floral waters composition. Dakar floral water contained 1,8-cineole (28.2%), terpinen-4-ol (20.3%)α-phellandrene-epoxide (15.9%)and α-terpineol (7%). The Saint-Louis floral water showed a high content of 1,8-cineole (19.2%), α-terpineol (15.4%), terpinen-4-ol (10.8%) and trans-pinocarveol (9.5%

O-glycosylation in plant and mammal cells: the use of chemical inhibitors to understand the biosynthesis and function of O-glycosylated proteins

Glycosylation is the most common posttranslational modification of proteins and consists of the addition of sugar moiety to proteins. The resulting glycosylated proteins are often secreted to the extracellular compartment or integrated into different cell organelles. This modification was identified in plant as well as in mammalian cells.  A number of plant and mammal proteins are either N- or O-glycosylated. This review focuses on O-glycosylation which refers to linkage of a glycan to hydroxyl group of serine, threonine or proline residues. O-glycosylation can be altered by the action of chemical inhibitors. For instance, 3,4-dehydro-L-proline, ethyl 3,4-dehydroxy benzoate and a,a-dipyridyl inhibit the activity of prolyl4-hydroxylase, a key enzyme for plant O-glycosylation. In addition, a small molecule inhibitor designated 1-68A inhibits the polypeptide N-acetylgalactosaminyltransferases of mammalian cells. The aim of this review is to summarize the role and mechanism of action of these inhibitors of O-glycosylation and their impact on cell development in plants and mammals

Colonization of the Mediterranean Basin by the vector biting midge species Culicoides imicola: an old story

Understanding the demographic history and genetic make-up of colonizing species is critical for inferring population sources and colonization routes. This is of main interest for designing accurate control measures in areas newly colonized by vector species of economically important pathogens. The biting midge Culicoides imicola is a major vector of Orbiviruses to livestock. Historically, the distribution of this species was limited to the Afrotropical region. Entomological surveys first revealed the presence of C. imicola in the south of the Mediterranean basin by the 1970's. Following recurrent reports of massive bluetongue outbreaks since the 1990s, the presence of the species was confirmed in northern areas. In this study, we addressed the chronology and processes of C. imicola colonization in the Mediterranean basin. We characterized the genetic structure of its populations across Mediterranean and African regions using both mitochondrial and nuclear markers, and combined phylogeographical analyses with population genetics and approximate Bayesian computation. We found a west/east genetic differentiation between populations, occurring both within Africa and within the Mediterranean basin. We demonstrated that three of these groups had experienced demographic expansions in the Pleistocene, probably because of climate changes during this period. Finally, we showed that C. imicola could have colonized the Mediterranean basin in the late Pleistocene or early Holocene through a single event of introduction; however we cannot exclude the hypothesis involving two routes of colonization. Thus, the recent bluetongue outbreaks are not linked to C. imicola colonization event, but rather to biological changes in the vector or the virus

La coiffe racinaire : sa formation et ses fonctions. Journées du GDR PHYP Biophysique et Biomécanique des plantes

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La coiffe racinaire : sa formation et ses fonctions. Journées du GDR PHYP Biophysique et Biomécanique des plantes

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Glycomolécules et défense racinaire: focus sur les AGPs et extensines

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