Showing papers on "Terpene published in 2002"
TL;DR: A terPene synthase gene is isolated from maize that exhibits only a low degree of sequence identity to previously identified terpene synthases, and the biochemical characteristics of the encoded enzyme are similar to those of terpenes synthases from both gymnosperms and dicotyledonous angiosperms, suggesting that catalysis involves a similar electrophilic reaction mechanism.
Abstract: Maize (Zea mays) emits a mixture of volatile compounds upon attack by the Egyptian cotton leafworm (Spodoptera littoralis). These substances, primarily mono- and sesquiterpenes, are used by parasitic wasps to locate the lepidopteran larvae, which are their natural hosts. This interaction among plant, lepidopteran larvae, and hymenopteran parasitoids benefits the plant and has been termed indirect defense. The committed step in the biosynthesis of the different skeletal types of mono- and sesquiterpenes is catalyzed by terpene synthases, a class of enzymes that forms a large variety of mono- and sesquiterpene products from prenyl diphosphate precursors. We isolated a terpene synthase gene, terpene synthase 1 (tps1), from maize that exhibits only a low degree of sequence identity to previously identified terpene synthases. Upon expression in a bacterial system, the encoded enzyme produced the acyclic sesquiterpenes, (E)-β-farnesene, (E,E)-farnesol, and (3R)-(E)-nerolidol, the last an intermediate in the formation of (3E)-4,8-dimethyl-1,3,7-nonatriene. Both (E)-β-farnesene and (3E)-4,8-dimethyl-1,3,7-nonatriene are prominent compounds of the maize volatile blend that is emitted after herbivore damage. The biochemical characteristics of the encoded enzyme are similar to those of terpene synthases from both gymnosperms and dicotyledonous angiosperms, suggesting that catalysis involves a similar electrophilic reaction mechanism. The transcript level of tps1 in the maize cv B73 was elevated after herbivory, mechanical damage, and treatment with elicitors. In contrast, the increase in the transcript level of the tps1 gene or gene homolog in the maize cv Delprim after herbivory was less pronounced, suggesting that the regulation of terpene synthase expression may vary among maize varieties.
247 citations
TL;DR: Labeling studies showed that de novo synthesis was not required for monoterpene or sesquiterpene release immediately following chemical treatment or insect feeding, and comparative measurements were made between aldehyde doses applied to the plant and levels naturally released from leaves with insect damage.
229 citations
TL;DR: The respective alcoholic terpenes carvacrol, linalool, and alpha-terpineol were used at 5% w/v in propylene glycol to increase the in vitro permeation of haloperidol through human skin, and the possible enhancement mechanism was elucidated with HP-stratum corneum (SC) binding studies, Fourier transform infrared spectroscopy, and differential scanning calorimetry.
159 citations
TL;DR: It is concluded that autoxidation of linalool is essential for its sensitizing potential and in sensitization studies in guinea pigs, linalOOL of high purity gave no reactions, while linalools that had been oxidized for 10 weeks sensitized the animals.
Abstract: Fragrances are among the most common causes of allergic contact dermatitis. The two monoterpenes linalool and d-limonene are the most frequently incorporated fragrance chemicals in scented products. Previous studies on d-limonene show that this monoterpene oxidizes on air exposure (autoxidation) and that allergenic oxidation products are formed. Due to structural similarities, linalool might also form allergenic oxidation products on air exposure. The aim of the present study was to study the autoxidation of linalool and to investigate the sensitizing potential of linalool before and after air exposure. Linalool was oxidized for 10 weeks and gas chromatographic analyses showed that the content of linalool decreased to about 80%. The chromatograms revealed the formation of other compounds during oxidation. One of the major oxidation products was isolated and identified as 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol. This substance is, to the best of our knowledge, described for the first time. In sensitization studies in guinea pigs, linalool of high purity gave no reactions, while linalool that had been oxidized for 10 weeks sensitized the animals. It is concluded that autoxidation of linalool is essential for its sensitizing potential.
131 citations
TL;DR: The hydro-distilled volatile oil of the Cinnamomum zeylanicum buds was analyzed using GC and GC-MS for the first time and a comparison of the chemical composition of the oil was made with that of flowers and fruits.
Abstract: The hydro-distilled volatile oil of the Cinnamomum zeylanicum (C. zeylanicum) buds was analyzed using GC and GC-MS for the first time. Thirty-four compounds representing approximately 98% of the oil was characterized. It consists of terpene hydrocarbons (78%) and oxygenated terpenoids (9%). alpha-Bergamotene (27.38%) and alpha-copaene (23.05%) are found to be the major compounds. A comparison of the chemical composition of the oil was made with that of flowers and fruits.
95 citations
TL;DR: A soil pseudomonad Pseudomonas sp. strain PIN isolated by enrichment culture metabolized either α- or β-pinene via p -menthene derivatives such as limonene and p -cymene.
63 citations
TL;DR: In this article, a dynamic headspace technique was used to assess the effect of terpenoid volatiles on the perception of sweet taste in carrots and concluded that terpinolene plays only a minor role in masking sweet taste.
Abstract: Carrots were grown in controlled climate chambers at 9, 12, 15, 18 and 21 °C and at two plant densities. Descriptive sensory analysis was performed and terpenes were assessed by means of a dynamic headspace technique. The highest score for sweet taste was obtained in carrots grown at the lowest temperature, while bitter taste, terpenes and sugars showed increasing values with increasing growth temperature. Plant density had little or no effect on sensory quality or terpenoid volatiles. Higher temperatures (18 and 21 °C) led to higher contents of terpenoid volatiles in carrots. A high positive correlation between terpenes (a-terpinene, b-myrcene, trans-caryophyllene, farnesene, a- humulene) and sensory variables (terpene flavour, green flavour, earthy flavour, bitter taste, aftertaste) was found: 83% of the variation in terpenes was able to predict 82% of the sensory variables by means of partial least squares regression (PLS2). It was concluded that these terpenes were responsible for bitter taste and thus suppressed the perception of sweet taste in carrots. Terpinolene decreased with increasing growth temperature and probably plays only a minor role in masking sweet taste in carrots. # 2002 Society of Chemical Industry
54 citations
TL;DR: Northern blot analysis showed that the transformed root cultures expressed these genes at different levels during the culture cycle, representing an important step towards demonstrating the presence of the plastid-localized terpenoid biosynthetic pathway in these easily engineered in vitro cultures.
Abstract: Artemisia annua produces a large number of unique terpenoids, making it of particular interest as a source of phytochemicals and a useful model plant for studying terpenoid metabolism. The ability to engineer fast-growing in vitro cultures to produce terpenoids in high yield would be a dramatic step towards commercial use. Two distinct pathways have been characterized in higher plants leading to the biosynthesis of isopentenyl diphosphate, the common precursor to all terpenes: the cytosolic mevalonate pathway and the plastid-localized mevalonate-independent pathway. While transformed roots of A. annua have been demonstrated to be superior to whole plants in terms of yield of the sesquiterpene artemisinin, they appear to lack functional chloroplasts, bringing into question the presence of a functional mevalonate-independent pathway. Using a cDNA library made from these roots, we isolated two clones encoding deoxy-d-xylulose-5-phosphate synthase (DXPS) and deoxy-d-xylulose-5-phosphate reductoisomerase (DXPR). The biochemical function of both enzymes was confirmed by complementing E. coli dxps- and dxpr-mutants. Northern blot analysis showed that the transformed root cultures expressed these genes at different levels during the culture cycle. In addition, cultures grown in continuous light showed substantial increases in DXPS transcript levels compared to dark-grown cultures. These results represent an important step towards demonstrating the presence of the plastid-localized terpenoid biosynthetic pathway in these easily engineered in vitro cultures.
48 citations
TL;DR: In this paper, the enantiomeric ratios of the chiral terpenes were determined for the first time in blackcurrant berries by GC using a column with a stationary phase containing permethylated cyclodextrin (Chirasil-β-Dex).
Abstract: Relative amounts of volatile terpenes in berries of 10 different blackcurrant (Ribes nigrum L) cultivars were examined by solid phase microextraction/gas chromatography (SPME/GC). The optimisation of a variety of parameters affecting SPME enabled relative standard deviations from three replicates ranging from 2 to 12% to be achieved. Differences between cultivars in the proportions rather than in the qualitative composition of volatile terpenes were found, and the proportions of some terpenes were especially variable. Furthermore, the enantiomeric ratios of the chiral terpenes were determined for the first time in blackcurrant berries by GC using a column with a stationary phase containing permethylated cyclodextrin (Chirasil-β-Dex). The enantiomeric compositions of the majority of the chiral terpenes varied within a reasonably narrow range. However, the levels of two monoterpene alcohols, terpinen-4-ol and linalool, exhibited considerable variations amongst cultivars.
© 2002 Society of Chemical Industry
46 citations
Journal Article•
TL;DR: In this paper, changes in several physicochemical parameters of grape composition including pH, titratable acidity, soluble solids, weight, color, and phenolic content were examined for Gewurztraminer during ripening.
Abstract: Changes in several physicochemical parameters of grape composition including pH, titratable acidity, soluble solids, weight, color, and phenolic content were examined for Gewurztraminer during ripening. Free and potentially volatile terpenes obtained by distillation were also assessed spectrophotometrically using an acidified vanillin assay and by gas chromatography-mass spectrometry (GC-MS). The colorimetric values of potentially volatile terpenes were estimated to account for nearly 84% of the bound terpenes, and the values of the free volatile terpenes reflected primarily the content of unsaturated aldehydes rather than the free terpenes. A procedure using selected ions specific to terpenes was developed to accelerate the analysis time of GC-MS chromatograms. Based on selected ion chromatograms, higher correlations were found for the bound terpene concentrations in Gewurztraminer vis-a-vis total skin phenolics, skin anthocyanins, and the traditional maturity indices of soluble solids and titratable acidity as compared to free terpene content.
41 citations
Patent•
09 Dec 2002
TL;DR: In this paper, the authors described a formulation for prevention and treatment of a respiratory infection by inhaling a solution containing a single bioactive terpene, a bio-active ter pene mixture, or a liposome-terpene composition before or after the onset of infection.
Abstract: Composition and methods for prevention and treatment of a respiratory infection A composition comprising a single terpene, a terpene mixture, or a liposome-terpene (s) composition is disclosed The composition can be a true solution of an effective amount of an effective terpene and a carrier such as water The composition can be a suspension or emulsion of terpene, surfactant, and carrier The composition(s) of the invention can be administered before or after the onset of the disease Administration can be, for example, by spraying the respiratory tract with a solution of the present invention Prevention and treatment of a respiratory infection by the inhalation of a solution containing a single bioactive terpene, a bioactive terpene mixture, or a liposome-terpene(s) composition before or after the onset of the infection is described A true solution of terpene and water can be formed by mixing terpene and water at a solution-forming shear rate in the absence of a surfactant
Journal Article•
TL;DR: In this article, the CH2Cl2 extract of the aerial parts of Euphorbia heteradena yielded 24methylenecycloartanol, cycloart-25-en-3b,24-diol, cycle-art-22-and-end-3-b,25-dol, vomifoliol, 9-O-b-D-glucopyranoside, 3,4,3'-tri-Omethoxy ellagic acid, syringic acid, and scopoletin.
Abstract: Euphorbia heteradena Jaub. & Spach (Euphorbiaceae), a plant endemic to Turkey, has not been investigated previously. The CH2Cl2 extract of the aerial parts of Euphorbia heteradena yielded 24-methylenecycloartanol, cycloart-25-en-3b ,24-diol, cycloart-22-en-3b ,25-diol, vomifoliol, vomifoliol 9-O-b -D-glucopyranoside, 3,4,3'-tri-O-methoxy ellagic acid, syringic acid and scopoletin. The structures of the isolates were identified by high field spectroscopic methods including 1D and 2D NMR techniques.
TL;DR: Inhibitory interactions between dietary terpenes, as well as other plant secondary compounds, may impose a significant constraint on foliage consumption in the common brushtail possum, therefore explaining the obligatory generalist nature of this browsing marsupial and other generalist herbivores.
Abstract: 1. Brushtail possums (Trichosurus vulpecula) ingest large amounts of terpenes in their diet of Eucalyptus leaf. Previously, we showed that dietary terpenes induce the cytochrome P450 enzymes (CYPs) responsible for their metabolism. The present study examined the effects of various CYP inhibitors on the metabolism of 1,8-cineole, the major dietary terpene, by liver microsomes from the possum and rat. 2. Ketoconazole inhibited the major reactions of terpene-induced microsomes in both species: 9-hydroxylation in the possum and 2-hydroxylation in the rat. This suggests the involvement of CYP3A enzymes, although in the possum there was a lack of the expected inhibition by troleandomycin or activation by alpha-naphthoflavone, highlighting the differences between species in CYP forms. Diethyldithiocarbamate also inhibited 9-hydroxylation in the possum, indicating that a CYP2E1-like enzyme contributes to this reaction. 3. Three other dietary terpenes were potent competitive inhibitors of 9-hydroxylation in the possum. K(i) ( micro M) (mean +/- SE, n = 4) were: alpha-pinene, 4.4 +/- 1.1; limonene, 7.8 +/- 2.1; p-cymene, 44.3 +/- 11.2; cuminyl alcohol (a p-cymene metabolite), 6.0 +/- 0.8. It appears likely that p-cymene acts via its metabolite to inhibit 1,8-cineole metabolism. 4. Inhibitory interactions between dietary terpenes, as well as other plant secondary compounds, may impose a significant constraint on foliage consumption in the common brushtail possum, therefore explaining the obligatory generalist nature of this browsing marsupial and other generalist herbivores.
Journal Article•
TL;DR: In this article, the reaction rate constants of cis / trans -pinane-2-ol conversion to linalool and its following cyclization to 5-membered alcohols were evaluated.
Abstract: The regularities of pinane-2-ol isomerization over block catalyst under reagent pressure of 2–45 Torr and within a temperature range of 450–620 °C were studied. A scheme of key product—linalool, as well as side products—hydrocarbons and 5-membered cyclic alcohols formation was suggested. Light hydrocarbons C 1 –C 6 are formed by gas phase free radical pathway of pinane-2-ol destruction, hydrocarbons C 10 by linalool dehydration over catalyst surface acid centers, 5-membered cyclic alcohols by linalool intermolecular cyclization. The reaction rate constants of cis / trans -pinane-2-ol conversion to linalool and its following cyclization to 5-membered alcohols were evaluated. The linalool formation mechanism including the intermolecular interaction of OH group proton resulting in pinane ring opening was suggested.
TL;DR: In this paper, changes in the enantiomeric composition of chiral terpenes during ripening were studied in three different blackcurrant varieties (Hedda, Baldwin, and Ben Hope) by solid phase microextraction-gas chromatography (SPME-GC).
Abstract: Changes in the enantiomeric composition of chiral terpenes during ripening were studied in 3 different blackcurrant (Ribes nigrum L.) varieties (Hedda, Baldwin, and Ben Hope) by solid-phase microextraction-gas chromatography (SPME-GC). The enantiomeric distribution of some terpenes remained constant, whereas others (β-pinene, limonene, and α-phellandrene) exhibited considerable variation. These data are indicative of the occurrence of 2 new biochemical pathways reported in blackcurrant for the first time. The overall level of chiral and non-chiral terpenes was examined at different stages of ripening. A slight increase in alcohol terpenes and a substantial drop in monoterpene and sesquiterpene hydrocarbons was found in the latter stages.
TL;DR: Two new terpenoids, bakayanolide (1) and 2α-hydroxy-3β-methoxy-6-oxo-13α,14β,17α-lanosta-7,24-dien-21,16β-olide (2), together with the known compounds 6β-hydrox-3-oxoxo -13α-14β-17α -lanosta, 7,24dien -21, 16β -olide have been isolated from the ethanolic root extracts of Melia
Abstract: Two new terpenoids, bakayanolide (1) and 2α-hydroxy-3β-methoxy-6-oxo-13α,14β,17α-lanosta-7,24-dien-21,16β-olide (2), together with the known compounds 6β-hydroxy-3-oxo-13α,14β,17α-lanosta-7,24-dien-21,16β-olide (3), sendanolactone (4), kulactone (5), and β-sitosterol have been isolated from the ethanolic root extracts of Melia azedarach. Triterpenoids (4), (5), and β-sitosterol have been identified previously from M. azedarach, while it is the first instance of the isolation of (3) from this source. The identity of these compounds was established through extensive spectroscopic methods (infrared and mass spectroscopy, 1H and 13C nuclear magnetic resonance) as well as appropriate two-dimensional nuclear magnetic resonance experiments. Bakayanolide (1) belongs to the rare class of C11 odd terpenes. Compounds (3) and (4) possessed moderate cytotoxic activity against KB cell lines.
TL;DR: Three apianane terpenoids, rel -(5 S, 6 S, 7 S, 10 R, 12 S, 13 R )-7-hydroxyapiana-8,14-diene-11,16-dion-(22,6)-olide, rel −(5S, 6S, 7 R, 10R, 12S, 13 S )- 7-hydroxapiana -8, 14-diENE-11-16-dorion-( 22,6]-olide were isolated from the leaves of Salvia officinal
Abstract: Three apianane terpenoids, rel -(5 S , 6 S , 7 S , 10 R , 12 S , 13 R )-7-hydroxyapiana-8,14-diene-11,16-dion-(22,6)-olide, rel -(5 S , 6 S , 7 R , 10 R , 12 S , 13 R )-7-hydroxyapiana-8,14-diene-11,16-dion-(22,6)-olide and rel -(5 S , 6 S , 7 S , 10 R , 12 R , 13 S )-7-hydroxyapiana-8,14-diene-11,16-dion-(22,6)-olide were isolated from the leaves of Salvia officinalis , together with 15 known compounds, salvigenin, lupeol, β-sitosterol, stigmasterol, physcion, carnosol, rosmadial, rosmanol, epirosmanol, isorosmanol, columbaridione, atuntzensin A, miltirone, carnosic acid and 12- O -methyl carnosic acid. Their structures were established on the basis of spectral evidence.
01 Jan 2002
TL;DR: In this article, the authors studied the biochemical and physiological background involved in terpene biosynthesis and emission by plants and found that the largest proportions of the terpenoids emitted from vegetation consist of the hemiterpene isoprene, various monoterpenes and, much less important, certain sesquiterpenes.
Abstract: A major part of the volatile organic compounds (VOC) in the atmosphere originates from isoprenoids emitted from plants and in particular from trees (Sharkey et al. 1991; Helas et al. 1997; Kesselmeier and Staudt 1999). The largest proportions of the terpenoids emitted from vegetation consist of the hemiterpene isoprene, various monoterpenes and, much less important, certain sesquiterpenes. These days great importance is placed on monoterpene and isoprene emission due to their impact on atmospheric chemistry and ozone formation (Trainer et al. 1987; Lerdau et al. 1997). In order to obtain better estimates of biogenic terpene emissions, it is essential to understand the biochemical and physiological background involved in terpene biosynthesis and emission by plants.
TL;DR: In this article, a-Pinene isomerization was studied in gaseous and liquid phases on g-zirconium phosphate and rhodium g-ZIRconium phosphoric acid.
Abstract: a-Pinene isomerization was studied in gaseous and liquid phases on g-zirconium phosphate and rhodium g-zirconium phosphate. The first showed higher activity but lower reaction selectivity than the second, that led to tricyclic terpenes formation.
TL;DR: In this paper, the synthesis of chiral vanadatranes by reaction of oxovanadium(V) alcoholates with triethanolamine derivatives obtained from the terpenes (−)-β-pinene, (−)-limonene, and (−)-menthone is reported.
Patent•
09 Sep 2002TL;DR: In this article, the absorbent articles include an effective amount of an isoprenoid inhibitory compound to substantially inhibit the production of exotoxins by Gram positive bacteria.
Abstract: Absorbent articles, such as catamenial tampons, are disclosed. The absorbent articles include an effective amount of an isoprenoid inhibitory compound to substantially inhibit the production of exotoxins by Gram positive bacteria. The isoprenoid inhibitory compounds of the present invention include terpenes and terpenoids which substantially reduce the production of exotoxins by Gram positive bacteria.
01 Jan 2002
TL;DR: In this paper, aqueous Diels-Alder reaction was used to synthesize Limonene, a-terpineol, and terpinolene in water alone as medium without Lewis acid-catalysis.
Abstract: As part of our project involving the development of synthetic protocols utilizing aqueous reaction conditions, some naturally occurring terpenes have been synthesized in our laboratory. Limonene, a-terpineol, and terpinolene were indirectly prepared via aqueous Diels-Alder reaction. The Diels-Alder reactions were carried out in water alone as medium without Lewis acid catalysis to afford the intermediates that are subsequently transformed to the target compounds by conventional means.
TL;DR: In this paper, the gross structures and relative stereochemistry of actephilol A 1 and epiactephiloline A 2 were determined through extensive 2D NMR analysis.
Abstract: An investigation into the chemical constituents of a crude MeOH extract from a specimen of Actephila excelsa (family Euphorbiaceae), led to the isolation of two new epimeric aromatic terpenoids, actephilol A 1 and epiactephilol A 2. The gross structures and relative stereochemistry of 1 and 2 were determined through extensive 2D NMR analysis. (C) 2001 Elsevier Science Ltd. All rights reserved.
TL;DR: The chemical investigation of the aerial parts of Haplopappus multifolius afforded the new monoterpenoid ester 9-cis-p-coumaroyloxy-alpha-terpineol, the new diterpene 18-hydroxylabda-7,13Z-dien-15-oic acid and its known E-isomer.
Abstract: The chemical investigation of the aerial parts of Haplopappus multifolius afforded the new monoterpene 2,9-epoxy-p-menth-6-en-8-ol (7, haplopappol), the new monoterpenoid ester 9-cis-p-coumaroyloxy-alpha-terpineol (8, haplofolin), the new diterpene 18-hydroxylabda-7,13Z-dien-15-oic acid (6) and its known E-isomer (5). In addition, the known dihydroflavones 3',5-dihydroxy-4',7-dimethoxydihydroflavone and 3',4',5-trihydroxy-7-methoxydihydroflavone and the known dihydroflavonols 3',5-dihydroxy-4',7-dimethoxydihydroflavonol and 3',4',5-trihydroxy-3-acetyl-7-methoxydihydroflavonol were also obtained. The structural assignments of these compounds were made possible by the different spectroscopic measurements.