Chemical constituents, toxicity and antimicrobial activities of the essential oil of the leaves of Tectona grandis

The leaves of Tectona grandis (Verbanaceae) was subjected to hydrodistillation in order to obtain the essential oil from the plant. The pale yellow essential oil gave a percentage yield of 0.184%. Relative percentages of individual component were analyzed by GC/GC-MS. A total of fifty-four (54) constituents were identified representing 86.5% of the total essential oil fraction. Oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, apocarotenoids, phenylpropanoids and non-terpene derivatives were the various classes of compounds identified. The LC50 value from the brine shrimp toxicity assay was 183.29µg/ml. The oil extract was also subjected to antibacterial assay and it showed significant activities against all the clinical test organisms used except Pseudomonas aeruginos

Some families of big and stable bundles on K3 surfaces and on their Hilbert schemes of points

Here we investigate meaningful families of vector bundles on a very general polarized K3 surface (X,H) and on the corresponding Hyper--Kähler variety given by the Hilbert scheme of points X[k]:=Hilbk(X), for any integer k⩾2. In particular, we prove results concerning bigness and stability of such bundles. First, we give conditions on integers n such that the twist of the tangent bundle of X by the line bundle nH turns out to be big and stable on X; we then prove a similar result for a natural twist of the tangent bundle of X[k]. Next, by a careful analysis on Segre classes, we prove bigness and stability results for tautological bundles on X[k] arising either from line bundles or from Mukai-Lazarsfeld bundles, as well as from Ulrich bundles on X

A study of physicochemical properties, volatile component analysis and antioxidative properties of honey

Honey samples from five different floral origins were analysed through solid phase microextraction (SPME) with objective to identify and compare their volatile organic compound profile. In addition, the levels of water, HMF, free proline, total acidity, diastase activity and sugar content have also been reported. The samples showed adequate water and HMF content. Total phenolics varied from 75.6 to 98.5mg/g, while total flavonoids were comprised between 1.86 and 4.93 mg/g, expressed as quercetin equivalents (the lowest and highest values were also found for Eucalyptus honey and neem honey, respectively). The IC50 value for DPPH has been found to be ranged from 4.97 to 9.45mg/ml. The highest DPPH RSA was found in Eucalyptus honey, followed by mustard honey and neem hone

Chemical composition and biological activities of Daucus aureus essential oils from Eastern Algeria

The aim of this study was to investigate the chemical composition of the essential oils of three populations of Daucus aureus from three sites in Eastern Algeria (Setif, Constantine and Oum Elbouaghi) and to test their antibacterial and antioxidant activities. The essential oils were obtained by hydrodistillation and analyzed by GC and GC/MS. The major components were sabinene (30.6% and 36.2%), n-nonane (8.0% and 7.9%), α-pinene (5.5% and 6.3%) and 4-terpineol (4.4% and 6.0%) in D. aureus from Setif and Constantine populations essential oils, respectively; whereas, α-pinene (19.4%), β-pinene (12.0%) and p-cymene (12.2%) were the major components in Oum Elbouaghi essential oil population. The chemical compositions of D. aureus from Eastern Algeria are markedly different from those from Western Algeria, and likely represent new chemotypes. The antimicrobial activity of the essential oils was evaluated against four bacteria and one fungus, using the disc-diffusion method and minimal inhibitory concentration (MIC), whereas, the antioxidant activity of the essential oils was evaluated using the DPPH test. The results showed that the oils have an antimicrobial activity against the microorganisms tested, with minimal inhibitory concentration (MIC) values between 0.97 and 3.23 mg/mL and weaker antioxidant and DPPH radical scavenging activities were found in comparison to butylated hydroxyl toluene (BHT)

Thermally-Reconfigurable Quantum Photonic Circuits at Telecom Wavelength by Femtosecond Laser Micromachining

The importance of integrated quantum photonics in the telecom band resides on the possibility of interfacing with the optical network infrastructure developed for classical communications. In this framework, femtosecond laser written integrated photonic circuits, already assessed for quantum information experiments in the 800 nm wavelength range, have great potentials. In fact these circuits, written in glass, can be perfectly mode-matched at telecom wavelength to the in/out coupling fibers, which is a key requirement for a low-loss processing node in future quantum optical networks. In addition, for several applications quantum photonic devices will also need to be dynamically reconfigurable. Here we experimentally demonstrate the high performance of femtosecond laser written photonic circuits for quantum experiments in the telecom band and we show the use of thermal shifters, also fabricated by the same femtosecond laser, to accurately tune them. State-of-the-art manipulation of single and two-photon states is demonstrated, with fringe visibilities greater than 95%. This opens the way to the realization of reconfigurable quantum photonic circuits on this technological platform

Valorisation of hemp inflorescence after seed harvest: Cultivation site and harvest time influence agronomic characteristics and essential oil yield and composition

Cannabis sativa L. is a multipurpose crop, whose industrial varieties, complying with the 0.2% Δ9-tetrahydrocannabinol (THC) threshold set by the EU legislation, can be cultivated without restrictions by farmers. Other than its traditional use as a source of bast fibres from the stems, the fixed oil extracted from its seeds represents a valuable nutritional product. Its inflorescence is also a further exploitable threshing residue originating from seed harvest, as they can be used for the extraction of the essential oil (EO), a high-value added product. This study aims at contributing to the re-evaluation of industrial hemp cultivation as an agro-environmentally sustainable crop for the diversification of Mediterranean cropping systems, by exploring the possibility of recovering the EO from the inflorescence after seed harvest. The influence of the cultivation site (lowland and upland of Pisa province, Tuscany, central Italy) and the harvest time (August and September) have been investigated on the ‘Fedora 17’ monoecious hemp cultivar: the main agronomic traits in term of stem, seed and inflorescence production, as well as essential oil yield and composition have been evaluated. The crops harvested in September exhibited higher total dry yield as well as higher inflorescence and stem yields, while neither the site nor the harvesting period influenced the seed production, which was significantly influenced by harvest time x cultivation site interaction. Both seed fixed oil and crude protein content were affected by the cultivation site only, but in the opposite sense: the highest seed oil content was reached in the upland area, while the plants grown in the plain area exhibited the largest seed protein content. All the extracted EOs were rich in sesquiterpenes (mostly β-caryophyllene and its oxidized derivatives, and α-humulene), but monoterpene hydrocarbons were significantly represented as well (mainly α- and β-pinene, and myrcene). The EOs extraction yields were slightly higher in the earlier harvest for both sites

Aroma characterization of ripe date fruits (Phoemix dactylifera L.) from Algeria

The headspace of eight Algerian date varieties with low market value were analyzed for their aroma compounds using solid phase micro extraction and gas chromatography combined with mass spectrometry. In this study, 61 identified compounds were categorized in various chemical classes on the basis of their functional groups, alcohols, esters, aldehydes, terpenoids, ketones, hydrocarbons, and ethers. Twenty specific volatiles were found to be representative of a single variety and four shared molecules were exclusively observed in all the studied dates. Some dates such as Bent Qbala, Litima, and Timjouhart were statistically different from the other varieties which presented on the contrary a significant similarity between them. In the present study, forty eight new volatile compounds were identified which could be useful for the characterization of the Algerian date

Chemical compositions of Casuarina equisetifolia L., Eucalyptus toreliana L. and Ficus elastica Roxb. ex Hornem cultivated in Nigeria

AbstractEssential oils were obtained by separate hydrodistillation of three different plants cultivated in Nigeria and analysed comprehensively for their constituents by means of gas chromatography (GC) and gas chromatography-mass spectrometry (GC–MS). The leaf essential oil of Casuarina equisetifolia L. (Casuarinaceae) comprised mainly of pentadecanal (32.0%) and 1,8-cineole (13.1%), with significant amounts of apiole (7.2%), α-phellandrene (7.0%) and α-terpinene (6.9%), while the fruit oil was dominated by caryophyllene-oxide (11.7%), trans-linalool oxide (11.5%), 1,8-cineole (9.7%), α-terpineol (8.8%) and α-pinene (8.5%). On the other hand, 1,8-cineole (39.4%) and α-terpinyl acetate (10.7%) occurred in large quantities in the essential oils of the leaf of Eucalyptus toreliana L. (Myrtaceae). The oil also features high levels of sabinene (5.9%), caryophyllene-oxide (4.7%) and α-pinene (4.2%). The main compounds identified in the leaf oil of Ficus elastica Roxb. ex Hornem. (Moraceae) were 6,10,14-trimethyl-2-pentadecanone (25.9%), geranyl acetone (9.9%), heneicosene (8.4%) and 1,8-cineole (8.2%)

Essential oils against Varroa destructor: a soft way to fight the parasitic mite of Apis mellifera

Essential oils (EOs) extracted from the aromatic plants Artemisia annua, Artemisia verlotiorum, Cinnamomum verum, and Citrus reticulata were investigated as repellents against the honey bees parasitic mite Varroa destructor. In laboratory tests, all EOs except C. reticulata exerted significant repellent activity against the mite after 24 h exposure. C. verumwas the most effective EO against V. destructor (median effective concentration EC50 =1.30 μL L−1), and the least toxic against honey bees (EC50 = 13.29 μL L−1). Because of its high selectivity ratio (A. mellifera LD50/V. destructor EC50 = 10.22), C. verum EO was then tested to control varroosis in colonies in field trials. The results of open field tests confirmed the efficacy observed in the laboratory. After one week of treatment, colonies treated with the EO showed a significant reduction of V. destructor infestation (about 65% at the dose of 25.0 μL L−1) and no negative effects on A. mellifera. Overall, our experiment indicated that C. verum EO could be used to effectively control varroosis in the hive with no side effects on the bee colonies