Showing papers on "Terpene published in 2001"

Progress in plant metabolic engineering

Abstract: Plants have been estimated to collectively synthesize more than 30,000 different terpenoids, of which many have useful applications in the manufacture of foods, industrial compounds, and pharmaceuticals. Terpenoids are synthesized from the condensation, in a head to tail fashion, of 5-carbon isoprene (or hemiterpene) units. Major terpenoid classes include mono-, sesqui-, and diterpenes, which are mostly secondary metabolites, as well as tri- and tetraterpenes, which are generally primary metabolites. This large family of compounds includes essential molecules such as carotenoids, gibberellins, abscissic acid and brassinosteroids, sterols, and the phytol chains of chlorophylls, tocopherols, and quinones. However, the vast majority are secondary metabolites, such as the volatile constituents of essential oils, and complex molecules like the anticancer drug paclitaxel that are thought to act as defensive agents (1).

Classification of Terpenoids according to the Methylerythritolphosphate or the Mevalonate Pathway with Natural12C/13C Isotope Ratios: Dynamic Allocation of Resources in Induced Plants

Abstract: Plants utilize two different pathways for the biosynthesis of isopentenyl diphosphate, the universal building block of all terpenes. Application of compound-specific isotope-ratio mass spectrometry (GC-C-IRMS) to volatile terpenoids allows distinction between the pathways on the basis of natural 12 C/13 C ratios.

Molecular scaffolds for chemical wizardry: Learning nature's rules for terpene cyclases

Abstract: Most people are familiar with terpenes whether they know it or not. These are the compounds that give many of our foods wonderful aromas and tastes and many of our household cleaning agents their fresh scents. But these are just some of the obvious ways we have taken advantage of these compounds. Biologically, terpenes are immensely important compounds in plants, fungi, bacteria, and insects that provide unique means for these organisms to sense and interact with their environment as well as serve as hormones that orchestrate developmental programs. For example, plants emit a wide range of terpenes that attract beneficial insects (1). Some plant families are notable also for their ability to synthesize and secrete antimicrobial terpenes as a defense compound against fungal and bacterial challenges (2). Still other plants that occupy resource-limited habitats such as deserts are known to constitutively secrete terpenes into their rhizosphere as a means of inhibiting the growth of competitor plant species (3). Fungi and bacteria likewise are known to synthesize a plethora of terpenes (4). Gibberella fujikuroi produces the well characterized plant growth regulator gibberellic acid, a diterpene, when it infects rice (5). This infection process results in unusually tall rice plants that can lodge easily and plants having other developmental abnormalities. Fusarium species and other relatives probably represent an even greater agricultural problem, because these fungi produce particularly noxious terpenes known as mycotoxins when they infect wheat and other stored grains (6).

Biotransformation of terpenoids by microorganisms

Abstract: In recent years, the flavour market has undergone a tremendous ‘back-to-nature’ demand, which is illustrated by the consumers' preference for ‘natural’ flavouring substances instead of synthetic ‘artificial’ compounds. These natural products can be obtained by extraction from plant material, but they can also be produced by biotechnological processes using micro-organisms. De novo synthesis of ‘bioflavours’, such as volatile esters, and biotransformation of monoterpenes are fields of investigation that gain a growing interest. Terpenes are obtained from the essential oil of many plants and are relatively cheap. They are usually isolated from the oils by rectification. This renders abundant monoterpenes, such as α-pinene and limonene, inexpensive starting materials for chemical and biochemical transformations. The fungal biotransformation of these natural precursors to more valuable aroma compounds offers a very interesting alternative source of natural flavours. This review article deals with the biotransformation of some monoterpenoids and sesquiterpenoids by both fungi and bacteria. As substrates myrcene, ocimene, geraniol, nerol, citronellol, citral, citronellal, linalool, limonene (and related compounds), pinenes, menthol, camphor, pulegone, ionones, nerolidol, farnesol, caryophyllene, valencene, patchoulol, etc… are discussed.

A New Multiflorane Triterpenoid Ester from Momordica cochinchinensis Spreng

Abstract: A new triterpenoid ester 3,29-di-O-(p-methoxy)benzoylmultiflora-8-ene-3 alpha,29-diol-7-one from the seeds of Momordica cochinchinensis Spreng has been isolated. Its structure was elucidated by spectroscopic evidence and confirmed by X-ray crystallography.

Synthesis of gelatin–PVA adsorbent and its application in the separation of ginkgo flavonol glycosides and terpene lactones

Abstract: Spherical adsorbents derived from the glutaraldehyde cross-linked hybrid of gelatin and polyvinyl alcohol (PVA) were synthesized, and their adsorption selectivity for ginkgo flavonol glycosides and terpene lactones was also investigated in detail. An adsorbent with an appropriate gelatin content can selectively adsorb flavonol glycosides with a high adsorption capacity based mainly on hydrogen bond interactions, while showing only a fairly low adsorption capacity for terpene lactones. A much higher adsorption affinity of flavonol glycosides than that of terpene was calculated from the adsorption isotherms. Thus, a simple preparative separation procedure for ginkgo flavonol glycosides and terpene lactones from a ginkgo leaf was established. An enriched extract containing flavonol glycosides of up to 60% and terpene lactones as low as 0.2% and an extract with a terpene lactones content up to 30% was prepared by this method, respectively.

Changes of volatile compounds during heating of bacuri pulp.

Abstract: The formation of volatile compounds from precursors or through chemical rearrangement during heat treatment of bacuri pulp at fruit natural pH were studied using simultaneous distillation/extraction (SDE) technique. An increase of the quantities of oxygenated and hydrocarbon terpenes and, to a lesser degree, aldehydes, was observed after SDE at pH 3, relative to the other extraction methods used, SDE at neutral pH and solid phase extraction (SPE). More particularly, linalool, linalool furanoxides, alpha-terpineol, hotrienol, nerol oxide, nerol, and geraniol were isolated in more important quantities after the first treatment than after the others. These results can be partially explained by the hydrolysis of glycosidically bound compounds previously identified in bacuri. Other pathways such as polyol rearrangements were also involved. The formation of linalool and alpha-terpineol was probably the result of the rearrangement of 2,6-dimethyloct-1-ene-3,7-diol. Moreover, it was assumed that oxidation reactions occurred during SDE at pH 3; more particularly, linalool pyranoxides partially resulted from nonenzymatic oxidation of linalool. When SDE was performed at pH 3, an increase of furfural and 4-methoxy-2,5-dimethyl-3(2H)-furanone was noticed. The modifications of the concentration of aliphatic aldehydes, known as lipid oxidation compounds, and of fatty acid esters were in good agreement with the observed decrease of palmitic and linoleic acid concentrations during this treatment. Moreover, important amounts of 2-acetyl-1-pyrroline were found in the SDE extract recovered at pH 7.

Reactions of some terpenes and their derivatives with acylating agents in the presence of aluminosilicate catalysts

Abstract: Reactions of camphene, α-fenchene, limonene, caryophyllene, α- and β-pinenes, verbenol, walterol, and verbenone with acylating agents in the presence of clay K-10 and wide-porous β-zeolite were studied. Presumable schemes and rules of the occurring processes were considered.

Terpenes from Leaves of Guarea macrophylla (Meliaceae).

Abstract: The dichloromethane extract from the leaves of Guarea macrophylla (Meliaceae) was submitted to adsorption chromatography. Guai-6-en-10beta-ol, isopimara-7,15-dien-2alpha-ol and cycloarta-23,25-dien-3-one were isolated and identified by spectroscopic data, mainly by 1H and 13C NMR analyses; eight other known terpenoids were also isolated.

GC-MS analysis of different solvent extracts of ginger

Abstract: Essential oil, extracted from the rhizomes of ginger, was analysed by GC-MS. Thirty-five, 36 and 44 constituents were identified respectively from the methanol, ethyl acetate and hexane extracts. Principal constituents detected in the three extracts were terpenes, but the composition and contents of the terpenes were different. The contents of total terpenes and sesquiterpenes increased with increasing polarity of the solvents used for extraction, but the content of monoterpenes decreased. The contents of unsaturated sesquiterpenes with antioxidant activity increased with increasing polarity of extracting solvents. It is shown that the antioxidant activity of ginger extracts increases with increasing polarity of solvents used for extraction.

Seasonal changes of flavonol glycosides and terpene lactone contents of Ginkgo biloba L.

Abstract: Flavonol glycosides and terpene lactone contents in leaves, stem and root of Ginkgo biloba L. 2\|yr\|old seedling as well as adult tree were determined in relation to the seasonal changes. Terpene lactone content of leaves increased gradually in spring with a maximum in late summer and early fall, thereafter decreased; terpene lactone of root and stem appeared similarity changes as leaves but maintained high content in dormancy stage in winter, then declined to the lowest when sprout in spring. Terpene lactone content of stem were the lowest, corresponding to 1/3 of leaves and 1/2 of root while bilobalide in leaves had a high ratio of total terpene lactone. Terpene lactone content decreased with tree age increment, which may be related to its biosynthetic activity decreasing. Flavonol glycosides content appeared higher in young leaves in spring, quercetin was major aglycone in leaves of long shoot, and kaempferol in leaves of short shoot. The relative mechanisms of diffenent components in different seasons and plant parts were discussed briefly.

Inhibition of exoprotein production in absorbent articles using isoprenoids

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

Use of terpene compounds for decreased release of arachidonic acids and mediators of inflammation

Abstract: medicine, pharmacy. SUBSTANCE: invention proposes the use of saturated mono- or bicyclic terpene alcohols, ethers, ketones or thiols for inhibition of release of arachidonic acid from phospholipide storage of human cells or for inhibition of release and synthesis of mediators of inflammation and cytokines from human cells. Invention proposes active components of drugs with indicated properties. Invention reveals the novel mechanism of effect of the known in medicine terpenes, for example, menthol, terpenethiol, carone, camphor, borneol, carane, pinane, bornane. EFFECT: new mechanism of terpene effect. 6 dwg, 2 ex

Synthesis of Terpenophenols via Direct Alkylation of Phenols by Terpenes

Abstract: Literature data on the alkylation of phenolic compounds by mono-, sesqui-, and diterpenes in the presence of various catalysts are reviewed.