Search results for " volatile"
showing 10 items of 312 documents
Up-regulation of 1-deoxy-D-xylulose-5-phosphate synthase enhances production of essential oils in transgenic spike lavender.
2006
Abstract Spike lavender (Lavandula latifolia) is an aromatic shrub cultivated worldwide for the production of essential oils. The major constituents of these oils are monoterpenes, which are obtained from isopentenyl diphosphate and dimethylallyl diphosphate precursors through the plastidial methylerythritol phosphate (MEP) pathway and/or the cytosolic mevalonate pathway. 1-Deoxy-d-xylulose-5-P synthase (DXS) catalyzes the first step of the MEP pathway. A cDNA coding for the Arabidopsis (Arabidopsis thaliana) DXS was constitutively expressed in spike lavender. Gas chromatography/mass spectrometry analyses revealed that transgenic plants accumulated significantly more essential oils compared…
Deoxyxylulose 5-phosphate reductoisomerase is not a rate-determining enzyme for essential oil production in spike lavender
2014
[EN] Spike lavender (Lavandula latifolia) is an economically important aromatic plant producing essential oils, whose components (mostly monoterpenes) are mainly synthesized through the plastidial methylerythritol 4-phosphate (MEP) pathway. 1-Deoxy-d-xylulose-5-phosphate (DXP) synthase (DXS), that catalyzes the first step of the MEP pathway, plays a crucial role in monoterpene precursors biosynthesis in spike lavender. To date, however, it is not known whether the DXP reductoisomerase (DXR), that catalyzes the conversion of DXP into MEP, is also a rate-limiting enzyme for the biosynthesis of monoterpenes in spike lavender. To investigate it, we generated transgenic spike lavender plants con…
Influence of Feeding and Oviposition by Phytophagous Pentatomids on Photosynthesis of Herbaceous Plants
2010
Abstract Feeding by herbivorous insects may change photosynthetic activity of host plants. We studied how feeding and oviposition by herbivorous stink bugs, Murgantia histrionica and Nezara viridula (Heteroptera: Pentatomidae), affect photosynthetic parameters of Brassica oleracea (savoy cabbage) and Phaseolus vulgaris (French bean). First, we measured photosynthetic gas exchange, chlorophyll fluorescence imaging, and emission of induced volatile organic compounds (VOC) immediately after feeding and during a post-feeding period. Photosynthesis decreased rapidly and substantially in B. oleracea and P. vulgaris infested by feeding bugs. Stomatal conductance did not decrease proportionally wit…
Up-regulation of an N-terminal truncated 3-hydroxy-3-methylglutaryl CoA reductase enhances production of essential oils and sterols in transgenic Lav…
2007
Spike lavender (Lavandula latifolia) essential oil is widely used in the perfume, cosmetic, flavouring and pharmaceutical industries. Thus, modifications of yield and composition of this essential oil by genetic engineering should have important scientific and commercial applications. We generated transgenic spike lavender plants expressing the Arabidopsis thaliana HMG1 cDNA, encoding the catalytic domain of 3-hydroxy-3-methylglutaryl CoA reductase (HMGR1S), a key enzyme of the mevalonic acid (MVA) pathway. Transgenic T0 plants accumulated significantly more essential oil constituents as compared to controls (up to 2.1- and 1.8-fold in leaves and flowers, respectively). Enhanced expression …
Chemical Composition and Antimicrobial Activity of the Essential Oils from Three Chemotypes of Origanum vulgare L. ssp. hirtum (Link) Ietswaart Growi…
2009
Essential oils obtained from inflorescences of three Origanum vulgare L.ssp. hirtum (Link) Ietswaart samples, growing wild in different locations in Campania (Southern Italy), were analysed. Three chemotypes were found: the first, with a prevalence of carvacrol/thymol; the second, characterized by the prevalence of thymol/alpha-terpineol; the third, featuring a prevalence of linalyl acetate and linalool. This chemical study attempts to provide a contribution in shedding light on the relationship between chemical composition and biotypes and/or chemotypes in Origanum vulgare ssp. hirtum. The essential oils were also evaluated for their antibacterial activity against 10 selected microorganism…
Chemical composition and anticancer activity of essential oils of Mediterranean sage (Salvia officinalis L.) grown in different environmental conditi…
2013
Salvia officinalis L. can be found worldwide and its leaves are commonly used as ingredient in food industry. Sage essential oil is applied in the treatment of a range of diseases and has been shown to possess different biological activities. The objectives of our research were to study the effects of environment on crop, chemical composition and anticancer activity on S. officinalis essential oil. Sage was cultivated at eighteen experimental sites in south-central Italy (Molise) in different growing environments. The essential oils (S1-S18), extracted by hydrodistillation, were analyzed by GC and CG/MS. Results show that the main components were α-thujone, camphor, borneol, γ-muurolene and…
Volatile constituents of aerial parts ofCentaurea sibthorpii(Sect. Carduiformes, Asteraceae) from Greece and their biological activity
2008
The volatile constituents of the aerial parts of Centaurea sibthorpii [Sect. Carduiformes, Asteraceae] collected in Greece were extracted by hydrodistillation and analysed by GC and GC-MS. Altogether 63 components were identified. Fatty acids and sesquiterpenoidic compounds were the most abundant components in the oil. A study on the biological activity of the oil showed no action against Gram-positive and Gram-negative bacteria.
Antimicrobial and antioxidant properties of the essential oil of Salvia lanigera from Cyprus
2010
The essential oil of aerial parts of Salvia lanigera Poir. (Lamiaceae) growing wild in Cyprus was obtained by hydrodistillation and was analysed by GC and GC-MS. A total of 67 compounds, representing 93.6% of the oil, were identified, and the major components were showed to be thymol (12.1%), hexadecanoic acid (6.0%), carvacrol and α-thujone (5.7%). The essential oil was assayed for its antioxidant and antimicrobial activities. Antimicrobial activity of the oil, evaluated using the broth dilution method, resulted higher against Gram-positive bacteria than the other referenced strains tested. Antioxidant activity of the oil was evaluated by using DPPH and FRAP methods together with three ant…
Chemotaxonomic value of the essential oil compounds in species of Teucrium pumilum aggregate
2000
Volatile compounds from the aerial parts of Teucrium lepicephalum Pau and Teucrium carolipaui C. Vicioso ex Pau, both belonging to the Teucrium pumilum aggregate, were analysed by capillary GC and GC-MS. From the common and specific compounds (mono- and sesquiterpenes) of the two taxa, chemical characterization was carried out and taxonomic relationships were assessed. Application of the cluster and k-means discriminant analysis shows a differential chemical relationship between T. lepicephalum and Teucrium carolipaui.
Volatile components from flower-heads of Centaurea nicaeensis All., C. parlatoris Helder and C. solstitialis L. ssp. schouwii (DC.) Dostál growing wi…
2008
The volatile constituents of the flowerheads of Centaurea nicaeensis All., C. parlatoris Helder and C. solstitialis L. ssp. schouwii (DC.) Dostal were extracted by hydrodistillation and analysed by GC and GC-MS. Altogether 113 components were identified. Fatty acids and hydrocarbons were the most abundant components in the oils. Caryophyllene and caryophyllene oxide were the main compounds of the sesquiterpene fraction. The study on the biological activity of the oils shows no significant activity.