Essential oils from Calyptranthes concinna, C. lucida and C. rubella (Myrtaceae)

Os óleos essenciais de Calyptranthes concinna, C. lucida e C. rubella, coletadas no sul do Brasil, foram analisados por GC/FID e GC/MS. Sessenta e dois constituintes foram identificados representando cerca de 98% do óleo. Todas as amostras mostraram-se ricas em sesquiterpenos cíclicos (mais de 90%), principalmente aquelas da via de ciclização dos cadinanos, bisabolanos e germacranos. Os principais constituintes caracterizados foram biciclogermacreno (22,1% em C. concinna; 11,7% em C. rubella), cis-calameneno (10,3% em C. concinna), betacariofileno (16,5% em C. rubella; 9,4% em C. lucida), beta-bisaboleno (25,5% em C. lucida), espatulenol (15,4% em C. rubella) e óxido de cariofileno (7,6% em C. concinna).Essential oils from Calyptranthes concinna, C. lucida and C. rubella, collected in Southern Brazil, were analyzed by GC and GC/MS. Sixty-two compounds were identified representing about 98% of the oil contents. All samples were rich in cyclic sesquiterpenes (more than 90 %), mainly those from cadinane, bisabolane and germacrane cyclization pathway. The mainly components characterized were bicyclogermacrene (22.1% in C. concinna;11.7% in C. rubella), cis-calamenene (10.3% in C. concinna), beta-caryophyllene (16.5% in C. rubella; 9.4% in C. lucida), beta-bisabolene (25.5% in C. lucida), spathulenol (15.4% in C. rubella) and caryophyllene oxide (7.6% in C. concinna)

Antiplasmodial volatile extracts from Cleistopholis patens Engler & Diels and Uvariastrum pierreanum Engl. (Engl. & Diels) (Annonaceae) growing in Cameroon

In a search for alternative treatment for malaria, plant-derived essential oils extracted from the stem barks and leaves of Cleistopholis patens and Uvariastrum pierreanum (Annonaceae) were evaluated in vitro for antiplasmodial activity against the W2 strain of Plasmodium falciparum. The oils were obtained from 500 g each of stem barks and leaves, respectively, by hydrodistillation, using a Clevenger-type apparatus with the following yields: 0.23% and 0.19% for C. patens and 0.1% and 0.3% for U. pierreanum (w/w relative to dried material weight). Analysis of 10% (v/v) oil in hexane by gas chromatography and mass spectrometry identified only terpenoids in the oils, with over 81% sesquiterpene hydrocarbons in C. patens extracts and U. pierreanum stem bark oil, while the leaf oil from the latter species was found to contain a majority of monoterpenes. For C. patens, the major components were α-copaene, δ-cadinene, and germacrene D for the stem bark oil and β-caryophyllene, germacrene D, and germacrene B for the leaf oil. The stem bark oil of U. pierreanum was found to contain mainly β-bisabolene and α-bisabolol, while α- and β-pinenes were more abundant in the leaf extract. Concentrations of oils obtained by diluting 1-mg/mL stock solutions were tested against P. falciparum in culture. The oils were active, with IC50 values of 9.19 and 15.19 μg/mL for the stem bark and leaf oils, respectively, of C. patens and 6.08 and 13.96 μg/mL, respectively, for those from U. pierreanum. These results indicate that essential oils may offer a promising alternative for the development of new antimalarials

Volatile composition of <I>Clitocybe amoenolens</I>, <I>Tricholoma caligatum</I> and <I>Hebeloma radicosum</I>

La composition de l\u27extrait volatil de Clitocybe amoenolens, Tricholoma caligatum et Hebeloma radicosum a été analysée sur matériel frais par chromatographie en phase gazeuse couplée à la spectrométrie de masse. Vingt-et-un, seize et vingt-trois composés ont été identifiés respectivement pour les trois champignons. Le (E)-cinnamate de méthyle a été trouvé dans chacun d\u27eux en quantités variables. Le (E)-cinnamate de méthyle, le benzoate de méthyle, le (E)-nérolidol et l\u27anthranilate de méthyle sont les composés clés de l\u27odeur de C. amoenolens. L\u27association du (E)-cinnamate de méthyle et des dérivés indoliques semble contribuer largement à l\u27odeur florale complexe, devenant nauséeuse avec l\u27âge, de T. caligatum; les dérivés indoliques pourraient présenter un intérêt chimiotaxonomique pour le genre Tricholoma. Différents dérivés aromatiques (benzaldehyde, 2-phényléthanal, 2-phényléthanol, acide phenylacétique) sont responsables de l\u27odeur d\u27amande amère avec une note florale d\u27Hebeloma radicosum.The volatile extracts composition of fresh Clitocybe amoenolens, Tricholoma caligatum and Hebeloma radicosum were analysed by Gas Chromatography-Mass Spectrometry. Twenty-one, sixteen and twenty-three components were identified, respectively. Methyl-(E)-cinnamate was found in the three analysed mushrooms at various amounts. Methyl-(E)-cinnamate and methyl-benzoate as well as (E)-nerolidol and methyl- anthranilate were the key odorants of C. amoenolens floral odor. Combined methyl-(E)-cinnamate and indole derivatives should largely contribute to the complex floral odor of T. caligatum with a nauseous note when aged; the latter volatiles could be of chemotaxonomic interest for the genus Tricholoma. Various aromatic derivatives (benzaldehyde, 2-phenylethanal, 2-phenylethanol, phenylacetic acid) were responsible for the almond-like odor with a floral note of Hebeloma radicosum.</p

Volatile constituents of <i>Kyllinga erectas</i>

Article

Investigation of low frequency giant magnetoelectric torque effect

International audienc

Diel variation in fig volatiles across syconium development: making sense of scents

Plants produce volatile organic compounds (VOCs) in a variety of contexts that include response to abiotic and biotic stresses, attraction of pollinators and parasitoids, and repulsion of herbivores. Some of these VOCs may also exhibit diel variation in emission. In Ficus racemosa, we examined variation in VOCs released by fig syconia throughout syconium development and between day and night. Syconia are globular enclosed inflorescences that serve as developing nurseries for pollinating and parasitic fig wasps. Syconia are attacked by gallers early in their development, serviced by pollinators in mid phase, and are attractive to parasitoids in response to the development of gallers at later stages. VOC bouquets of the different development phases of the syconium were distinctive, as were their day and night VOC profiles. VOCs such as alpha-muurolene were characteristic of the pollen-receptive diurnal phase, and may serve to attract the diurnally-active pollinating wasps. Diel patterns of release of volatiles could not be correlated with their predicted volatility as determined by Henry's law constants at ambient temperatures. Therefore, factors other than Henry's law constant such as stomatal conductance or VOC synthesis must explain diel variation in VOC emission. A novel use of weighted gene co-expression network analysis (WGCNA) on the volatilome resulted in seven distinct modules of co-emitted VOCs that could be interpreted on the basis of syconium ecology. Some modules were characterized by the response of fig syconia to early galling by parasitic wasps and consisted largely of green leaf volatiles (GLVs). Other modules, that could be characterized by a combination of syconia response to oviposition and tissue feeding by larvae of herbivorous galler pollinators as well as of parasitized wasps, consisted largely of putative herbivore-induced plant volatiles (HIPVs). We demonstrated the usefulness of WGCNA analysis of the volatilome in making sense of the scents produced by the syconia at different stages and diel phases of their development

Changes in essential oil composition in Saint John’s wort (Hypericum perforatum L.) aerial parts during its phenological cycle

International audienc

The chemical ecology of seed dispersal in monoecious and dioecious figs

In the nursery pollination system of figs (Ficus, Moraceae), flower-bearing receptacles called syconia breed pollinating wasps and are units of both pollination and seed dispersal. Pollinators and mammalian seed dispersers are attracted to syconia by volatile organic compounds (VOCs). In monoecious figs, syconia produce both wasps and seeds, while in (gyno)dioecious figs, male (gall) fig trees produce wasps and female (seed) fig trees produce seeds. VOCs were collected using dynamic headspace adsorption methods on freshly collected figs from different trees using Super Q® collection traps. VOC profiles were determined using gas chromatography–mass spectrometry (GC–MS).The VOC profile of receptive and dispersal phase figs were clearly different only in the dioecious mammal-dispersed Ficus hispida but not in dioecious bird-dispersed F. exasperata and monoecious bird-dispersed F. tsjahela. The VOC profile of dispersal phase female figs was clearly different from that of male figs only in F. hispida but not in F. exasperata, as predicted from the phenology of syconium production which only in F. hispida overlaps between male and female trees. Greater difference in VOC profile in F. hispida might ensure preferential removal of seed figs by dispersal agents when gall figs are simultaneously available.The VOC profile of only mammal-dispersed female figs of F. hispida had high levels of fatty acid derivatives such as amyl-acetates and 2-heptanone, while monoterpenes, sesquiterpenes and shikimic acid derivatives were predominant in the other syconial types. A bird- and mammal-repellent compound methyl anthranilate occurred only in gall figs of both dioecious species, as expected, since gall figs containing wasp pollinators should not be consumed by dispersal agents