Monoterpene Esters Research Articles

Terpenoids and bisbibenzyls from Chinese liverworts Conocephalum conicum and Dumortiera hirsuta

Four new monoterpene esters, 2α,5β-dihydroxybornane-2-cinnamate (1), 2α,5β-dihydroxybornane-5-acetyl-2-cinnamate (2), 2α,5β-dihydroxybornane-2-p-hydroxycinnamate (3) and 2α,5β-dihydroxy-bornane-2-cis-p-hydroxycinnamate (4), together with a known compound 3,4-dimethoxystyrene (5) were isolated from Chinese liverwort Conocephalum conicum and six known compounds, 5,7-dihydroxycalamenene (6), 7-hydroxycalamenene (7), lunularin (8), riccardin C (9), marchantin C (10) and riccardin D (11) were isolated from Dumortiera hirsuta. Their structures were elucidated by extensive spectral analysis and chemical correlations. Compounds 1 and 8 showed moderate cytotoxicity against human HepG2 cells with IC50 4.5 μg/ml and 7.4 μg/ml, respectively, while compound 8 also showed antimicrobacterial activity against Pseudomonas aeruginosa with minimum inhibitory concentration at 64 μg/ml.

Predominant adsorption of sesquiterpene constituents of lavender, tea tree, lemongrass and thyme thymol oils on hairless mouse and human hairs in an aromatic bath

Summary Adsorption of the major constituents of lavender, tea tree, lemongrass and thyme thymol essential oils on hairless mouse skin was determined in an aromatic bath. Adsorption occurred in a concentration-dependent manner. Sesquiterpene hydrocarbons showed the most dominant adsorption, especially in dilute solution. This was followed by the hydrophobic monoterpene hydrocarbon and ester. The relatively hydrophilic monoterpene alcohol, phenol and aldehyde constituents were poorly adsorbed. The same tendency was observed on hairy mice, mouse hairs, guinea pig hairs and human hairs. This selective adsorption of sesquiterpenes was not observed on natural rubber but observed on keratin, a major protein forming skin and hairs. When examined using the authentic compounds, the sesquiterpene hydrocarbon (β-caryophyllene) and the sesquiterpenols (farnesol, nerolidol, and bisabolol) exhibited the highest adsorption, while the monoterpene limonene and linalyl acetate showed moderate adsorption, and the monoterpenic camphor, linalool, perillaldehyde, and thymol showed low adsorption. Human hairs were suggested to be an alternative to mouse skin for adsorption studies of essential oils.

Analysis of the essential oil from aerial parts of Eupatorium cannabinum subsp. corsicum (L.) by gas chromatography with electron impact and chemical ionization mass spectrometry

Eupatorium cannabinum subsp. corsicum (L.), an aromatic plant, is an endemic subspecies from Corsica. The essential oil from aerial parts of E. cannabinum subsp. corsicum was studied by GC, GC/MS and 13C NMR. One hundred and forty-seven components were identified representing 93.6% of the total amount. The main constituents are germacrene D (28.5%), α-phellandrene (19.0%) and para-cymene (5.2%). A particularity of this essential oil is the presence of monoterpene esters derived from nerol, lavandulol, borneol, thymol and 8,9-dehydrothymol. These compounds have been investigated using GC/MS in different ionization modes like electron impact (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI).

(+)‐Bornyl Piperate, a New Monoterpene Ester from Piper aff. pedicellatum Roots.

AbstractFor Abstract see ChemInform Abstract in Full Text.

(+)-Bornyl piperate, a new monoterpene ester from Piper aff. pedicellatum roots.

A new monoterpene ester, (+)-bornyl piperate was isolated from the underground roots of Piper aff. pedicellatum and its structure was elucidated on the basis of spectroscopic evidence and confirmed by X-ray analysis. The compound crystallizes in the triclinic space group P1 with a=7.3232(4) A, b=11.4705(7) A, c=23.2520(14) A, V=1943.6(2) A(3). This compound showed an antituberculosis activity against Mycobacterium tuberculosis (H(37)Ra strain) with the minimum inhibitor concentration (MIC) of 25 microg/ml.

Anti-inflammatory activity of linalool and linalyl acetate constituents of essential oils.

Linalool and linalyl acetate are the principal components of many essential oils known to possess several biological activities, attributable to these monoterpene compounds. In this work, we evaluated individually the anti-inflammatory properties of (-) linalool, that is, the natural occurring enantiomer, and its racemate form, present in various amounts in distilled or extracted essential oils. Because in the linalool-containing essential oils, linalyl acetate, is frequently present, we also examined the anti-inflammatory action of this monoterpene ester. Carrageenin-induced edema in rats was used as a model of inflammation. The experimental data indicate that both the pure enantiomer and its racemate induced, after systemic administration, a reduction of edema. Moreover, the pure enantiomer, at a dose of 25 mg/kg, elicited a delayed and more prolonged effect, while the racemate form induced a significant reduction of the edema only one hour after carrageenin administration. At higher doses, no differences were observed between the (-) enantiomer and the racemate; a further increase in the dose of both forms did not result in an increased effect at any time of observation. The effects of equi-molar doses of linalyl acetate on local edema were less relevant and more delayed than that of the corresponding alcohol. These finding suggest a typical pro-drug behavior of linalyl acetate. The results obtained indicate that linalool and the corresponding acetate play a major role in the anti-inflammatory activity displayed by the essential oils containing them, and provide further evidence suggesting that linalool and linalyl acetate-producing species are potentially anti-inflammatory agents.

Study of lipase-catalyzed hydrolysis of some monoterpene esters

Studies of the hydrolysis of bornyl, citronellyl, geranyl, and terpenyl acetates by commercially available lipases of Candida rugosa, Rhizopus arrhizus, and Mucor miehei are presented. The hydrolysis of these monoterpene esters is investigated at various temperatures and pHs, and the time dependence of the percentage of esters hydrolysed is studied. The catalytic activities of the lipases in hydrolysing the esters are compared and, overall, it is observed that under the experimental conditions used the nonspecific lipase from C. rugosa produces the highest yields of the monoterpene alcohols in comparison to the primary-ester specific lipases such as R. arrhizus and M. miehei. A rate kinetic model has been used to understand the time dependence of the yield of the product acid.

Study of lipase-catalyzed hydrolysis of some monoterpene esters

Studies of the hydrolysis of bornyl, citronellyl, geranyl, and terpenyl acetates by commercially available lipases of Candida rugosa, Rhizopus arrhizus, and Mucor miehei are presented. The hydrolysis of these monoterpene esters is investigated at various temperatures and pHs, and the time dependence of the percentage of esters hydrolysed is studied. The catalytic activities of the lipases in hydrolysing the esters are compared and, overall, it is observed that under the experimental conditions used the nonspecific lipase from C. rugosa produces the highest yields of the monoterpene alcohols in comparison to the primary-ester specific lipases such as R. arrhizus and M. miehei. A rate kinetic model has been used to understand the time dependence of the yield of the product acid.Key words: enzymatic hydrolysis, kinetics, lipase, monoterpene esters.

Chemistry of the oil gland secretion of Collohmannia gigantea (Acari: Oribatida).

The chemistry of the lemon-scented oil gland secretion of Collohmannia gigantea, a middle-derivative mixonomatan oribatid mite, was investigated by gas chromatography - mass spectrometry. Gas chromatographic profiles of whole body extracts of C. gigantea revealed two distinct chromatographic zones, the first containing a set of six volatile compounds, comprising the lemon-scented monoterpene aldehydes neral and geranial, the scented monoterpene ester neryl formate, a distinctly scented aromatic aldehyde (2-hydroxy-6-methyl-benzaldehyde = 2,6-HMBD), and the two non-scented hydrocarbons, tridecane and pentadecane. All six components appeared to be present in steady relative proportions in scenting mites only, indicating their unity within the scented secretion. In contrast, the components of the second chromatographic zone were less volatile and found in both, scenting and nonscenting mites. Chemically, they represent a set of fatty acids of already known cuticular origin. The secretion bouquet of the first chromatographic zone was linked with oil glands by histochemical means: large amounts of aldehydes were present only in oil gland reservoirs, not in any other region of the mite body. While chemical profiles of oil gland secretions of several dozen astigmatid mites are known, only one other oribatid oil gland composition, from a desmonomatan species, has been elucidated, being almost the same as that of C. gigantea. Moreover, all components of these two secretions are widely distributed amongst astigmatid mite species and may also be common in a restricted set of middle-derivative oribatids. These findings are consistent with the idea of astigmatid mite origin from a mixonomatan-desmonomatan group.

Identification of rumanite (Romanian amber) as thermally altered succinite (Baltic amber)

Romanian amber (rumanite) has been considered to be a separate species of fossil resin for more than a century. While earlier investigators held it to be very similar to succinite (Baltic amber), modern scholars have assigned it a distinctly different botanical origin. We have found that almost all of the constituents of the ether-soluble fractions of 13 specimens of authentic rumanite identified by gas chromatography–mass spectrometry have previously been reported in the soluble fraction of succinite, including succinic acid and its monoterpene esters. Additionally and significantly, the soluble fraction of rumanite contains a number defunctionalized compounds that do not preexist in succinite, but that are produced by pyrolysis of whole succinite or of its insoluble polymeric fraction. Simultaneous methylation pyrolysis–gas chromatography–mass spectrometry of the polymeric fraction of seven of the rumanite specimens yielded further copious amounts of dimethyl succinate, a number of diterpene resin acid methyl esters, and additional defunctionalized compounds known to be pyrolysis products of succinite. The evidence shows conclusively that the botanical origin of rumanite is not distinct from that of succinite. Rather, rumanite is a succinite that has suffered partial thermal degradation in the course of the folding of the Oligocene Kliwa sandstone formation in which it is most commonly found.

苔類ジャゴケ及びフジウロコゴケの植物化学的研究

Four hundred samples of Conocephalum conicum, collected in various places have been analyzed by GC-MS. This resulted in the presence of three chemo-types of C. conicum. One of them elaborate (-)-sabinene (type-I) as a major compound. The other two types characteristically contained (+)-bornyl acetate (type-II) and methyl cinnamate (type-III) as major constituent respectively. The structures of three new monoterpenic esters, isolated from the ether extract of C. conicum (type-I and/or II) have been established by chemical and spectral means. They were shown to be monoterpenic esters of (+)-borneol and p-coumaric acid derivatives. The ether extract of the liverwort Chiloscyphus polyanthos afforded sesquiterpenoids which are enantiomeric to those found in another liverwort Lepidozia vitrea. The absolute configurations of the sesquiterpenoids found in the C. polyanthos were determined by spectroscopic evidence, chemical derivatization and/or x-ray crystallographic analysis. The ether extract of the liverwort Porella perrottetiana afforded (-)-alpha-eudesmol, which showed an opposite sign of the optical rotation to that found in higher plants. Present work on the absolute configuration and an optical purity of (-)-alpha-eudesmol strongly suggested that the positive values (e.g. +28.5 degrees) described in many previous papers should be revised. Since the absolute configuration of (-)-alpha-eudesmol was identical to that (+)-beta-eudesmol found in the higher plants, it was apparent that the expression of the positive sign might be revised to (-)-alpha-eudesmol. The optical purity, reconfirmation of the absolute configuration and synthesis of (-)-alpha-eudesmol will be discussed.

The Production of Pyrethrins by Plant Cell and Tissue Cultures of Chrysanthemum cinerariaefolium and Tagetes Species

Pyrethrins, the most economically important natural insecticide, comprise a group of six closely related monoterpene esters. The industrial production is based on their extraction from Chrysanthemum cinerariaefolium (Pyrethrum) capitula. The world production of natural pyrethrins still falls short of global market demand stimulating the research in in vitro production as an alternative to conventional cultivation methods. The different biotechnological alternatives such as callus cultures, shoot and root cultures, plant cell suspension cultures, and bioconversion of precursors by means of enzymatic synthesis or genetically engineered microorganisms, as well as the progress achieved in methods for the identification and quantitation of insecticidal compounds have been reviewed. Although technology for plant cell culture exists, industrial applications have, to date, been limited due to both the low economical viability and technological feasibility at large scale. Bioconversion of readily available precursors looks more attractive, but more research is needed before this technology is used for the industrial production of pyrethrins.

The Production of Pyrethrins by Plant Cell and Tissue Cultures of Chrysanthemum cinerariaefolium and Tagetes Species

Pyrethrins, the most economically important natural insecticide, comprise a group of six closely related monoterpene esters. The industrial production is based on their extraction from Chrysanthemum cinerariaefolium (Pyrethrum) capitula. The world production of natural pyrethrins still falls short of global market demand stimulating the research in in vitro production as an alternative to conventional cultivation methods. The different biotechnological alternatives such as callus cultures, shoot and root cultures, plant cell suspension cultures, and bioconversion of precursors by means of enzymatic synthesis or genetically engineered microorganisms, as well as the progress achieved in methods for the identification and quantitation of insecticidal compounds have been reviewed. Although technology for plant cell culture exists, industrial applications have, to date, been limited due to both the low economical viability and technological feasibility at large scale. Bioconversion of readily available precursors looks more attractive, but more research is needed before this technology is used for the industrial production of pyrethrins.

The Production of Pyrethrins by Plant Cell and Tissue Cultures of Chrysanthemum cinerariaefolium and Tagetes Species

Pyrethrins, the most economically important natural insecticide, comprise a group of six closely related monoterpene esters. The industrial production is based on their extraction from Chrysanthemu...

Synthesis of monoterpene esters by alcoholysis reaction with Mucor miehei lipase in a solvent‐free system

AbstractThe syntheses of geranyl acetate and citronellyl acetate by alcoholysis reaction catalyzed by immobilized lipase from Mucor miehei was studied for the first time in a solvent‐free system. Reactions were carried out at a terpene alcohol/acyl donor molar ratio of 1:5 with Lipozyme at 10% of the total weight of the reactants in a solvent‐free system. Incubations were carried out at 55 to 60°C for ethyl and butyl acetates as acyl donors, whereas for methyl acetate the incubation temperature was 40 to 45°C. Excess concentration of acyl donor increases the percentage of geranyl acetate and citronellyl acetate, while excess of terpene alcohol concentration decreases the same. Yields from 75 to 77% molar conversion (90 to 98% conversion, w/w) were obtained after 8 to 28 h of reaction time.

A comparative study on three chemo-types of the liverwort Conocephalum conicum using volatile constituents

GC-mass spectrometric analysis of 280 samples of Conocephalum conicum, collected in various places showed the presence of three chemo-types. One elaborated (−)-sabinene (type I) as the major compound the second produced (+)-bornyl acetate (type II) and the third contained methyl cinnamate (type III) as the major constituent. The structures of three new monoterpenic esters were established by chemical and spectral means.

Effects of two monoterpene esters, valtrate and didrovaltrate, isolated from Valeriana wallichii, on the ultrastructure of hepatoma cells in culture

AbstractThe action of two monoterpene esters isolated from Valeriana wallichii D.C., valtrate and didrovaltrate, has been studied on the ultrastructure of HTC hepatoma cells in culture. These two compounds are cytoxic and inhibit the synthesis of DNA and protein in tumour cells. The study using scanning and transmission electron microscopy showed that, prior to cell death, the two compounds cause the disappearance of membrane microvilli, a large distension of the endoplasmic reticulum and a marked condensation of the mitochondria. Furthermore, valtrate rapidly leads to the rounding and detachment of cells cultivated in layers whereas, in the presence of didrovaltrate, the cells remain spread out and tightly attached to the support, even after treatment with trypsin.

GC/MS Analysis of the Leaf Oil ofCryptomeria japonicaD. Don from Reunion Island

ABSTRACT GC/MS analysis of the leaf oil of Cryptomeria japonica D. Don obtained from Reunion allowed us to identify more than 70 compounds thanks to our SPECMA data bank. Among the volatiles, monoterpene hydrocarbons (45%), monoterpene alcohols (10%), monoterpene esters (2%), sesquiterpenes (25%) and diterpenes (12%) have been found. The presence of a moderate amount of α-kaurene (10%) and its 16-hydroxylated derivative (0.6%) was noted. The composition of the C. japonica from Reunion was found to be similar to that originating from Japan. Unidentified sesquiterpene and diterpene derivatives require further attention.

Friedolabdanes and other constituents from chilean Haplopappus species

From the aerial parts of Haplopappus pulchellus two new labdanes and six friedolabdanes were isolated while H. arbutoides afforded in addition to known labdanes five new ones, two clerodanes and a cyperone derivative. Haplopappus remyanus gave two further labdanes, six monoterpene esters and three known flavanones while H. rengifoanus afforded large amounts of liguloxide. Haplopappus marginalis gave no characteristic compounds. The chemistry of the genus is discussed.

Volatile Constituents ofPeucedanum palustre

The essential oils of fruits, stalks, leaves, and roots of PEUCEDANUM PALUSTRE (L.) Moench (Apiaceae) were analyzed by various chromatographic and spectroscopic methods. While the fruit and stalk oils consist nearly exclusively of monoterpene hydrocarbons, the essential leaf oil comprises monoterpene hydrocarbons (47%), sesquiter-pene hydrocarbons (38%), aliphatic alcohols and esters (7%), and traces of oxygenated sesquiterpenoids. 35 constituents of this oil could be identified. The detailed analysis of the complex root oil, mainly consisting of mono- and sesquiterpenoids, resulted in identification of 68 compounds, representing about 92% of the oil. The occurrence of some new sesquiterpenoids with unusual carbon skeletons is noteworthy.