Effet du séchage à l'air libre des feuilles d'E. camaldulensis sur le rendement et la composition de l'huile essentielle

Au cours du stockage des feuilles d'E.camaldulensis à l'air libre, le rendement en huile essentielle augmente de 54% (maximum atteint le 16 ème jour ) . Le broyage ne semble pas avoir un effet sur le phénomène étudié. Par contre le stockage à froid, l'étuvage à 70·C et le blanchiment à 90°C l'inhibent. Donc, l'augmentation de la teneur enH.E., durant les deux premières semaines de séchage à l'air libre et à l'ombre, est d'origine enzymatique.Effect of drying of E. camaldulensis leaves on the yield and the chemical composition of the essential oilDuring the storage of E. camaldulensis leaves under shade, the essential oil yield increased by 54% (maximum reached the 16th day). The milling does'nt seem to affect the studied processus. In contrast cold storage, oven drying at 70°C and Bleaching at 90·C inhibit it. So, The increasing of the oil yield, during the first two weeks, is due to enzymatic activity

Huiles essentielles de six espèces xérophyles d'Eucalyptus: effet du milieu sur les rendements et la composition chimique

Les huiles essentielles (HE) de six espèces xérophyles d'Eucalyptus plantées dans deux zones de la région denMarrakech (Jbilet et Takerkoust) ont été examinées. Les espèces étudiées ont donné des rendements relativement intéressants. Pour l'E.salmonophloia il a atteint 5%. 41 composés ont été identifiés par chromatographie en phase gazeuse. Le cinéole reste le composé majoritaire de la plupart des huiles essentielles analysées: sa teneur varie entre 40 et 70%. Le rendement en HE, ainsi que la composition chimique de ces dernières varient d'une espèce à une autre et d'un milieu à un autre. Les échantillons prélevés dans la zone de Jbilet sont mieux pourvus en p-cymène et en spathulénol. Ceux récoltés dans la zone de Takarkoust présentent en revanche des teneurs en a-pinène et en bornéol nettement plus élevées. Le taux du 1,8-cinéole ne présente pas de variations importantes entre les régions étudiées pour les échantillons de la mâme espèce.Essential oils of six xerophyl Eucalyptus species: effect of location on the yield and the chemical compositionThe essential oils of six xerophyl Eucalyptus species, planted in two sites of Marrakech region (Jbilet and Takerkoust) have been analysed. The studied species gave interestingyields. For E.salmonophloia the essential oil content reached 5%. 41 components have been identified by gas chromatography. The cineol stays the major compound of the most analysed essential oils: its content varies between 40 and 70%. The essential oil yield and the chemical composition vary within the species and the location. The samples 'taken in the Jbilet site are richer in p-cymene and spathulenol. Those harvested in the site ofTakerkoust have, however, high contents of a-pinene and borneol. The content of cineol does'nt change significantly, from a site to an other, for the same species

Divergent Chemical Cues Elicit Seed Collecting by Ants in an Obligate Multi-Species Mutualism in Lowland Amazonia

In lowland Amazonian rainforests, specific ants collect seeds of several plant species and cultivate them in arboreal carton nests, forming species-specific symbioses called ant-gardens (AGs). In this obligate mutualism, ants depend on the plants for nest stability and the plants depend on ant nests for substrate and nutrients. AG ants and plants are abundant, dominant members of lowland Amazonian ecosystems, but the cues ants use to recognize the seeds are poorly understood. To address the chemical basis of the ant-seed interaction, we surveyed seed chemistry in nine AG species and eight non-AG congeners. We detected seven phenolic and terpenoid volatiles common to seeds of all or most of the AG species, but a blend of the shared compounds was not attractive to the AG ant Camponotus femoratus. We also analyzed seeds of three AG species (Anthurium gracile, Codonanthe uleana, and Peperomia macrostachya) using behavior-guided fractionation. At least one chromatographic fraction of each seed extract elicited retrieval behavior in C. femoratus, but the active fractions of the three plant species differed in polarity and chemical composition, indicating that shared compounds alone did not explain seed-carrying behavior. We suggest that the various AG seed species must elicit seed-carrying with different chemical cues

Isolation of Moroccan Ammi visnaga oil : comparison between hydrodistillation, steam distillation and supercritical fluid extraction.

International audienc

Volatiles, color characteristics and other physico–chemical parameters of commercial Moroccan honeys

Seven commercial Moroccan honeys were considered for chemical characterisation. Volatile fraction, total polyphenols content, antioxidant and antiradical activities were evaluated by employing different analytical methodologies. Several physical parameters such as refractive index, pH, water content, solids content and colour were measured. Volatile fraction revealed an abundant presence of cis- and trans-linalool oxide in the seven studied samples. The presence of high levels of compounds related to the Maillard reaction, like furfural and hydroxymethylfurfural, could be the result of thermal treatments used to liquefy commercial honeys or of long storage times. The CIE L*a*b*Cab*hab° chromatic coordinates confirmed the advanced stage of the Maillard reaction, showing L*values lower than the common values found for honey of similar typologie