Foliage sesquiterpenes of Dacrydium cupressinum: identification,variation and biosynthesis

The major sesquiterpenes in the foliage of Dacrydium cupressinum are α-longipinene, longifolene, longibornyl acetate, caryophyllene, caryophyllene oxide, humulene, α- and β-selinene, β- and δ-elemene, aromadendrene and the rare 9βH-caryophyllene. Sesquiterpene levels vary greatly from tree to tree. As this variation is largely independent of environmental factors, genetic control is proposed. Longifolene and α-longipinene levels are closely correlated, as are those of caryophyllene and humulene. The biosynthetic implications of these correlations are discussed.     

Biosynthesis of sesquiterpenes in Hymenaea inferred from their quantitative co-occurrence

Leaf pocket resins of 11 species of the tropical arborescent genus Hymenaea are virtually identical qualitatively, but of widely varying quantitative proportions. Within this large range of variability, several strong positive quantitative correlations between resin constituents were found, especially between caryophyllene and β-humulene and between γ-muurolene and δ-cadinene. These data lead to clarification of sesquiterpene biosynthetic routes in Hymenaea. In addition, quantitative relationships found among caryophyllene, α- and β-selinene, γ-muurolene and δ-cadinene are explained only with difficulty by long accepted biosynthetic pathways, and the intermediacy of germacrenes is suggested.     

A guaianolide and other constituents from Lychnophora species

A new guaianolide, 11 β,13-dihydroeremanthine, together with a caryophyllene derivative and pentacyclic triterpenes, has been isolated from Lychnophora species.     

Sesquiterpenes from Artemisia princeps

Copaene, cyperene, caryophyllene, β-farnesene, α-himachalene, γ-humulene and farnesyl acetate were isolated from the root of Artemisia princeps. As a result of isomerization studies on γ-humulene, the main constituent, a preferred conformation was proposed.     

12-Hydroxytovarol and derivatives from Thapsia villosa var. minor

The new germacrane esters 12-angeloyloxy- and 12-hydroxy-8-O-angeloyltovarol and 12-angeloyloxy-8-O-angeloylshiromodiol were isolated from T. villosa var. minor, and their structures established by spectral data and chemical correlations. The terpenoids geranyl acetate, δ-cadinene, γ-cadinene, γ-muurolene, β-caryophyllene and caryophyllene oxide were also isolated from the aerial parts.     

Sesquiterpenes of Barbilophozia species

Two isomeric olefins, α- and β-barbatene, apparently of a new tricyclic sesquiterpene skeleton (that of gymnomitrol), have been found in the liverworts Barbilophozia barbata, B. floerkei, B. lycopodioides, and B. attenuata. Additional components identified are alkanes, calamenene and α-alaskene. GLC suggests the presence of caryophyllene, longifolene, bazzanene and α-cedrene in minor amounts.     

Essential oil composition and variability of Hypericum perforatum L. growing in Lithuania

The composition of essential oils obtained from flowers and leaves in 11 accessions of Hypericum perforatum L. was analysed by GC and GC–MS. All the analysed oils were dominated by their oxygenated sesquiterpene fraction. Differences were attributed to the main components: caryophyllene oxide, spathulenol and viridiflorol. There were only a few monoterpenes in essential oil of all accessions. The data indicated some differences in sesquiterpene and aliphatic hydrocarbons, as well as in oxygenated aliphatics biosynthesis in flowers and leaves. The concentrations of β-caryophyllene and caryophyllene oxide in essential oils from leaves were higher than those from flowers, whereas dodecanol, spathulenol, viridiflorol, carotol and tetradecanol were present in higher quantities in flowers. Cluster analysis of all identified components grouped oils from flowers and from leaves into three clusters that corresponded with their major components: caryophyllene oxide, tetradecanal, tetradecanol and manool. Chemical variability of the analysed accessions seems likely to result from the genetic variability, since the influence of different environmental factors has been eliminated.     

Terpenes from Cantinoa (Lamiaceae) native to Rio Grande do Sul,South Brazil

Cantinoa althaeifolia, C. heterodon, C. mutabilis, C. stricta and C. sylvularum were investigated for the essential oil and exudate composition. The essential oils of these species, previously placed in the genus Hyptis, demonstrated the presence of at least 46 compounds, being β-pinene, δ-3-carene, β-caryophyllene, bicyclogermacrene, caryophyllene oxide and globulol the compounds present in higher amounts. Besides monoterpenes and sesquiterpenes, three species presented diterpenes. Kaurenoic acid was isolated from C. heterodon exudate and detected by gas chromatography in C. stricta and C. mutabilis. Although kaurane diterpenes are widely found in nature, their occurrence in Lamiaceae seems to be restricted to few genera.     

Composition of turpentine from Pinus edulis wood oleoresin

Monoterpenoids and sesquiterpenoid hydrocarbons of Pinus edulis wood oleoresin were analyzed by chromatographic and spectroscopic methods. Monoterpenoid hydrocarbons (20·3%) were composed mainly of α-pinene, with camphene, β-pinene, 3-carene, sabinene, myrcene, limonene, β-phellandrene, trans-ocimene and terpinolene in secondary to trace amounts. Oxygenated terpenoids (0.28%) contained bornyl acetate and verbenone as major constituents, and linalool, camphor, terpinene-4-ol, citronellyl acetate, borneol, neral, α-terpineol, citronellol, nerol, and geraniol in smaller amounts. Oleoresin contained 1·1% of acetogenins, composed mainly of ethyl caprylate. Sesquiterpenoid hydrocarbons were high (5·7%) in oleoresin) and were composed of germacrene D as a major constituent (36·6%), of γ-amorphene, α-copaene, and longifolene as secondary constituents (5–20%), and β-farnesene, α- and γ-murolenes, β₁-, γ-, δ-, and ε-cadinenes, α-amorphene, δ-guaiene, sibirene, α-cubebene, β-copaene, β-ylangene, sativene, cyclosativene, β-bourbonene, α- and γ-humulenes, caryophyllene, α-longipinene and longicyclene in smaller amounts. Composition of P. edulis and of P. monophylla turpentines was found to be similar, with percentage of ethyl caprylate being the best distinguishing criterion.     

Phenological variations of secondary metabolites from Hypericum triquetrifolium Turra

The essential oils and phenolic constituents from the aerial parts of Hypericum triquetrifolium Turra, were analyzed at three developmental stages (vegetative, flowering and fruiting stages). The highest content of oil (0.12% w/w) was obtained at full flowering. Whatever the analyzed stage, n-octane, α-pinene, β-caryophyllene, 2-methyloctane, n-nonane, α-longipinene, caryophyllene oxide and β-pinene were found to be the main compounds. However, their percentages varied with the phenological cycle. Analysis by RP-HPLC-DAD of the methanolic extracts enabled us to identify 14 phenolic components and rutin, hyperoside, quercitrin and quercetin were reported as the main components. With the exception of chlorogenic acid, kaempferol and amentoflavone, the content of the remaining identified phenolic components varied with the phonological cycle.     

Karyomorphological effects of two new oil formulations on Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

The cotton bollworm Helicoverpa armigera is a serious pest of many economically important crops. Since this pest has become resistant to the conventional synthetic insecticides, newer compounds and formulations are being developed against this insect pest. Many natural compounds isolated from the plants were tested against this pest. Among them Hyptis suaveolens and Melochia corchorifolia showed insecticidal properties against H. arnigera. Based on bioefficacy studies, caryophyllene and β-sitosterol were isolated from H. suaveolens and M. corchorifolia respectively. The isolated natural compounds were further developed as formulations in various combinations with neem (Azadirachta indica) and karanj (Pongamia pinnata) oils. The present study indicated that the formulations influenced the karyomorphology of H. armigera.     

Aroma volatiles of Cynara scolymus and Helianthus tuberosus

Samples of the aroma volatiles of globe artichoke and Jerusalem artichoke were obtained by well established methods and were analysed by routine GC and GC/MS. Eight sesquiterpene hydrocarbons afforded the major group of components (over 42%) in globe artichoke samples, with β-selinene (ca 32%) as the main constituent. Previously reported caryophyllene could not be detected. α-Cedrene was found to have globe artichoke aroma characteristics on odour evaluation of separated components at an odour port at the exit of the GC column. Jerusalem artichoke samples contained one major component (β-bisabolene, ca 51%) and a range of saturated long-chain hydrocarbons (ca 22%). The sesquiterpene presumably contributes appreciably to the characteristic flavour of Jerusalem artichoke. Both types of artichoke gave a low concentration of total volatiles.     

Role of colour and volatile in foraging behaviour of honeybee Apis cerana on Jacquemontia pentanthos

Floral visual and olfactory cues guide the insect visitors to the source of reward. This work addresses one such interaction between honeybee Apis cerana and a garden climber Jacquemontia pentanthos. Field studies have indicated that A. cerana showed preference to J. pentanthos over the other flowering plants during its visits for foraging. The objectives of the work is to understand the role of colour and scent in the attraction of Apis cerana to the host plant. Bioassays performed emphasized the involvement of colour and volatiles for the visits of A. cerana. Petals show high reflectance to ultraviolet light with ultraviolet absorbing regions in the centre which serve as a nectar guide. Gas chromatography linked electroanntenogram detector (GC-EAD) showed antennal response to the floral volatile of J. pentanthos identified as sesquiterpene β-caryophyllene. Behavioural studies have shown similar preference to β- caryophyllene as that of α-humulene. Our studies suggest an interplay of colour and volatiles cues for A. cerana visitation to Jacquemontia flowers and these findings are further supported by behavioural studies on.A. cerana.     

Identification des constituants de l'essence des aiguilles de Pinus pinaster

The chromatographic analysis of the volatile leaf oil of Pinus pinaster Ait. showed 42% of monoterpene hydrocarbons (α-pinene, camphene, β-pinene, myrcene, 3-carene, limonene, cis-ocimene, terpinolene, para-cymene, 35% of sesquiterpene hydrocarbons (cubebene, copaene, caryophyllene, humulene, germacrene D, α- and γ-muurolenes, δ- and γ-cadinenes) and 23% of oxygenated compounds including esters (linalyl, bornyl, geranyl, neryl and farnesyl acetates), alcohols (cis-hexenol, linalool, α-fenchol, trans-pinocarveol, terpinen-4-ol, α-terpineol, dihydrocarveol, guaiol, junenol and α-cadinol), one aldehyde (hexenal) and one ketone (piperitone). Three non terpenoid phenylethyl esters were also identified: phenylethyl isovalerate, methyl-2 burtyate and 3-3 dimethylacrylate. Some alcohols and mainly α-terpineol and linalool seemed to be formed during the steam distillation process, they were absent when the leaf oil was obtained by maceration of small portions of leaves in the usual solvents of terpenes.     

Sesquiterpene Deterrence of a Leaf-Tying Lepidopteran, Stenoma ferrocanella, on Hymenaea stigonocarpa in Central Brazil

Study of two populations of Hymenaea stigonocarpa in the central Brazilian cerrado (savanna/woodland) shows attack by a leaf-tying lepidopteran, Steoma ferrocanella, occurred after inferred peak concentration (% of leaf dry wt) of sesquiterpene leaf resins during leaf development. Also a highly statistically significant relationship existed between leaf-tier attack and level of caryophyllene in one population and γ-muurolene in the other population. The data from one population are consistent with laboratory experiments demonstrating highly significant dose-dependent effects of caryophyllene in Hymenaea leaf resin on mortaility of the lepidopteren Spodoptera exigua. Results from both populations support other evidence that changes in the amount of single terpenes in the mixture constituting the resin may have significant antiherbivore effects and, concomitantly, that herbivory may be a source of some of the leaf resin variation.     

A caryophyllene derivative from Fleischmannia pycnocephaloides

A new caryophyllene derivative, 15-acetoxy-5,6-dihydro-6,7-dehydrocaryophyllen-5-one, has been isolated from the roots of Fleischmannia pycnocephaloides. Other Fleischmannia sp. yielded previously known compounds.     

Essential oil in Betula spp. leaves naturally growing in Estonia

The essential oils of the leaves of Betula pendula Roth., Betula pubescens Ehrh., Betula humilis Schrank and Betula nana L. (Betulaceae), and B. pendula buds were obtained using hydrodistillation and their chemical compositions were analyzed using gas chromatography and gas chromatography – mass spectrometry. The yield of essential oil was the highest (0.27%) in leaves of. B. humilis and the lowest in the leaves of B. pendula (0.11%), B. pubescens (0.05%) and B. nana (traces). Overall, 35–60 compounds were identified representing more than 92% of the total volume of the oils investigated. The bicyclical sesquiterpenoids found in the essential oils extracted from the leaves of B. pendula, B. pubescens and B. humilis and from the buds of B. pendula where α-betulenol (20.4–33.1%), α-betulenol acetate (5,6–28.9%), β-betulenal (5.5–6.2%) and β-betulenol (2.0–5.8%). The buds of B. pendula contained more birkenal, (E)-β-caryophyllene, δ-cadinene and caryophyllene oxide, but less α-betulenol acetate, β-betulenal and aliphatic compounds than the oils extracted from the leaves investigated. The oil composition of B. humilis and B. nana leaves was studied for the first time. The content of essential oil of B. nana leaves was much more varied: the oil contained less bicyclical sesquiterpenoids and more aliphatic compounds than the other Betula species investigated. The findings of our study could be used in chemosystematics of birch species, especially for B. nana.     

Chemical composition and larvicidal activity of essential oils from Piper species

The larvicidal activity of essential oils of four species of Piper from the Amazon Forest was tested using third-instar larvae of Aedes aegypti. The oils were extracted by steam distillation and analyzed by GC and GC–MS. The main components isolated from each Piper species were as follows: viridiflorol (27.50%), aromadendrene (15.55%) and β-selinene (10.50%) from Piper gaudichaudianum; β-selinene (15.77%) and caryophyllene oxide (16.63%) from Piper humaytanum; dillapiol (54.70%) and myristicin (25.61%) from Piper permucronatum; and asaricin (27.37%) and myristicin (20.26%) from Piper hostmanianum. Amongst all essential oils tested, the most active against larvae of A. aegypti was the oil extracted from P. permucronatum, with a LC₅₀ = 36 μg/ml (LC₉₀ = 47 μg/ml), followed by the essential oil of P. hostmanianum, with a LC₅₀ = 54 μg/ml (LC₉₀ = 72 μg/ml). The oils with higher content of arylpropanoids were more active against larvae of A. aegypti.     

Composition of essential oil of <Emphasis Type="Italic">Artemisia scoparia</Emphasis> Waldst. et Kit. from Buryatia and Mongolia

Essential oil from the epigeal portion of Artemisia scoparia Waldst. et Kit. collected in different regions of Buryatia and Mongolia has been isolated using steam distillation. The yield of essential oil from the stems and leaves of A. scoparia collected in different regions of Buryatia and in the Selenga aymag of Mongolia ranged from 0.06 to 0.40%, that is, the variation was rather high. The composition of the oil was analyzed using chromatography with mass spectrometric detection on a gas chromatography device Agilent Packard HP 6890 N with a quadrupole mass spectrometric detector HP MSD 5973. The total number of compounds detected exceeded 100. The major components of Artemisia scoparia oil were the following: p-cymene (0.6–15.2%), limonene (0.1–6.3%), α-pinene (0.2–10.1%), β-pinene (0.4–8.9%), trans-β-ocimene (0.3–5.4%), caryophyllene (4.6–13.8%), germacrene D (11.5–40.3%), spathulenol (4.0–11.7%), and caryophyllene oxide (4.3–15.6%). Several chemotypes of essential oil from A. scoparia were identified according to the nature of the major components: 1) oil that contained acetylene hydrocarbons (from plants collected in Gilan, Mazandaran, Kashan, and Tigran provinces of Iran, Tajikistan, and the European part of the CIS); 2) oil that contained monoterpenes and aromatic compounds (from plants collected in the Khorasan province of Iran, India, and South Korea); and 3) oil that contained monoterpenes or aromatic and sesquiterpene compounds (from plants collected in Kazakhstan and Mongolia). The major components of A. scoparia essential oil obtained from Buryatian plants belonged to the classes of mono- and sesquiterpene compounds, and thus the oil can be assigned to the third chemotype characteristic of A. scoparia from geographically close regions.     

Caryophyllene derivatives from Pulicaria arabica

The aerial parts of Pulicaria arabica afforded in addition to known caryophyllene derivatives seven new ones. The configuration at C-11 of previously reported derivatives has to be corrected as followed from the observed NOEs.